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Rigging Questions

Discussion in 'Question of the Day' started by ship, Dec 27, 2005.

  1. ship

    ship Senior Team Emeritus Premium Member

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    400) What is the maximum safe working load of 1/8" galvanized wire rope?
    401) What is the approximate safe working load of a safety cable?
    402) What is the difference in SWL between a double saddle cable clamp and a malleable clamp?
    403) What is the percent efficiency of a drop forged wire rope clamp?
    404) What is the percent efficiency of a aluminum Nicopress sleeve and why are they not to be used on stage?
    405) What is the difference between SWLs for stage work and industry?
    406) What is the safe working load of a single spanset in the choker arrangement around 1x1 truss?
    407) What is the approximate sheer strength of a store bought 5/16" lag bolt?
    408) What is the Safe Working load of a 1200# SWL Rope with a Clove Hitch in it?
    409) What is Schedule 80 pipe?
    410)Which pipe is not measured the same as the rest of the pipe: Schedule 40 black pipe, PVC, Pneumatic, EMT, RMT, Aluminum, Galvanized, or Schedule 80?
    411) What is the difference between 1/4" NPT, 1/4" NF, and 1/4" NC nuts?
    412) What is the approximate bolt grade of Aircraft Grade Alloy Bolts?
    415) What is the purpose of washers in high strength fastening?
    416) Is there a difference in strength between zinc and plain steel fasteners?
    417) What would be the best washer for use when bolting to an I-Beam?
    418) When a rope or cable or wire breaks, why does it not break at the point it is being pulled from, instead it breaks somewhere between 9 an 36 inches from it?
    419) A Sling lifting 1,000 pounds is attached so to its load so it forms a 45/45/90° triangle between its two hanging points and the hook, what is the approximate load on each diagonal leg of the sling?
    420) In general when hanging things, the steeper the vertical angle of the cable from the hanging point, the ______ the load is on the cable.
    421) The proper way to un-reel wire rope or cable from the spool is from above or below?
    422) In coiling a right-lay cable, wire, or rope, the proper direction to coil is clockwise or counterclockwise?
    423) How do you “Mouse off” a shackle or turnbuckle?
    424) What does “Never Saddle a Dead Horse” mean?
    425) What are Legs, Boarders, Teasers and Tormenters, which is which and what if anything is the differences between the two general styles of drape?
    426) What is stronger in rigging components, bent stamped steel, cast steel plate, or forged steel?
    427) What is West Coasting?
    428) What is the average or normal speed in feet per minute of our 1 ton chain hoist?
    429) Are 1 ton chain hoists Polyphase, Induction, Synchronous, Split Phase, Capacitor, Repulsion, or Shaded-Pole motors?
    430) What is a fire link, what is its load rating, and how long of a service life does it have?
    431) What is Static Equilibrium in reference to a fly system?
    432) Mechanical advantage is what divided by applied force?
    433) What does the head block of a fly system do?
    434) What knot do you use to tie off a hemp lineset to a batten?
    435) What is the cable called a Sunday and what is it used for?
    436) What is a knuckle buster and what is it used for?
    437) Rope must be strong enough to support the load safely and absorb what three loadings for any particular application?
    438) Broken internal strands of wire or rope is an indication of what?
    439) A the groove of a sheave should be sized to support at least how much of a ropes circumference?
    440) Explain resultant forces applied on a block.
    441) On a beam, batten or truss with three evenly spaced supports on each end and the center, what is the percentage of load carried by the center and each end?
    442) In general, moving the end supports toward the center of a load does what to the percentage of the load carried?
    443) On a five lineset or post supported beam/truss/batten, which post(s) carries the most weight?
    444) Grid floors have their deck planks/steel mounted parallel or perpendicular to the proscenium?
    445) What is fleet angle, and how much is permissible?
    447) What is the difference between an Idler Pulley and a Mule Block?
    448) How do you tie off a line set to a pin rail?
    449) On a double-purchase counterweight system, how many feet does the batten travel for every 1' of arbor travel, and how many pounds of counterweight are required for every pound of load?
    450) Three reasons imported rigging hardware is never used on stage are: 1) the safety factor if stamped on the material is usually not published, 2) With only a country of origin (esp. China) stamped on the hardware, it is hard to trace liability, and what other reason?
    451) For stage rigging on the subject of reserve strength of wire rope, how many wires can be broken on a lineset before it should be replaced?
    452) Wire ropes with more strands have better fatigue resistance, but for the most part less strength, what is one other advantage cable with more strands?
    453) When installing a new wire rope, it should be taken off the spool so that the major bending is in the same or opposite direction as it was on the spool?
    454) By how much can installing wire rope in the wrong direction from the spool reduce the life of the wire rope?
    455) What two things will increasing sheave tread diameters do for wire rope?
    456) What two types of wire rope are permissible to use in hemp houses on hemp shives? Why?
    457) What does 6x37 IWRC stand for?
    458) What would be the advantage besides smaller bending radius, of using fiber core cable over solid or stranded core wire rope?
    459) For what two reasons is galvanized wire rope the standard cable for the industry over stainless steel?
    460) What are the differences between rotation resistant wire rope and sash cord wire ropes?
    461) Which type of wire rope is weakest and strongest, Bright Sash, Tiller Rope, Plow Steel, or Galvanized Wire Rope?
    462) On a trim chain with 1.1/2 wraps around the pipe, how do you attach the two ends of the chain to double the weight capacity of the trim chain?
    463) Why should you not use regular steel chain on a fly system?
    464) New trim chain comes with snap hooks/dog snaps, by current standards what is the purpose of it, and should you use a quick link, lap link, shackle, or grade 5 bolt to replace the snap hook? Why?
    465) How do you tie a circus knot, and what is it used for?
    466) On a batten, when a clove hitch is applied with wire rope clips above it, what is the efficiency of the attachment?
    467) When using turnbuckles on a fly system what is required to be done to them to make them safe?
    468) The proper sizing of a sheave to 7x19 aircraft cable D/d ratio is 4:1, 10:1, 25:1, or 50:1?
    469) Wire guide arbors are used for fly systems with grid heights under how many feet?
    470) Why are donut arbors frowned upon?
    471) Spreader bars should be used every how many feet on a counterweight arbor?
    472) What is the correct order to install 3 wire rope clips after a thimble?
    473) What is the proper torque to apply to 1/8" wire rope clips and what size nut is it?
    474) What is the proper order to install the crimps on a 1/8" nico sleeve and how many are required?
    475) What is the reason not to re-use nuts to bolts for purposes of rigging?
    476) What grade of bolt is used for most general purpose rigging applications?
    477) Abrasion on wire rope is the result of rubbing, what is the name for when little cracks appear on wire rope and which is potentially more serious?
    478) A wire broken under a tensile load that exceeds its strength is recognized by the “cup or cone configuration at the fracture point, coned break points indicate what?
    479) The number of broken wires allowable on the running ropes in one rope lay for a tower or pillar crane is six, how many are allowable per strand?
    480) A wire rope or electrical cable which has a tightly spiraling pig-tailed look when not under tension is the result of what?
    481) Little knots or distortions and displacements in the grain of a wire rope but flush to it, is the result of what?
    482) Big knots or distortions usually the wires from the inner core poking out of the wire rope are the result of what?
    483) What is the minimum lifting angle to the center plane on a drop forged sholulder verses normal eyebolt?
    484) Properly reeved splices in rope are considered to be how efficient?
    485) What are two ways to ensure a screw pin shackle will not un-screw? What other types of shackle are available?
    486) What should you do when two or more Spanset ends are to be installed on a chain hoist hook?
    487) When two spansets with hooks or safety cables are installed bridle style on a beam with 2 rig points, which way should the opening of the hook face inboard or outboard?
    488) What is the standard length of a new Schedule 40 pipe from a plumbing supplier?
    489) What is the difference between the main and the grand drape?
    490) What is an Olio and how is it different from show drops?
    492) What is the difference between a show portal and a leg?
    493) Where is the plaster line on stage?
    494) What is the purpose of a Tab Drape?
    495) What is a purchase line?
    496) How are tableu or tabs rigged differently than pleated drapes?
    497) To ensure fullness, how should you hang a drape?
    498) When hanging drapes how many eyelets of over lap should there be between seems?
    499) How are the on-stage ends of a leg tied off?
    500) How do you go about bouncing the main?
    501) When lowering a drop, electric, or other scenery on a fly system, where should your primary attention and eyes be directed?
    502) How many lights can be pulled off an electric before it should be re-weighted?
    503) 2-3%, 3-5%, 10-15%, or 20-25% is the maximum allowable voltage drop for a motor?
    504) Load speed is appreciably below rated speed is caused from voltage drop or what?
    505) Chain hoists should or should not be stored or transported at their pre-set limits, Why?
    506) Why shouldn’t you operate or store a chain-hoist on its side? (2 reasons)
    507) What is the maximum load rating of a Genie ST-24 Super Tower?
    508) What is the standard batten weight including cable, gack, and standard instrument weight per fixture?
    509) What is the difference in SWL between brass and aluminum Nicopress sleeves?
    510) When rigging a sling in the choker, how is the shackle installed, and which has the highest SWL multiplier capacity, Wire rope, Fiber Webbing, or Chain?
    511) Which is the proper formula for deadhang tension? (Length of member in tension) = L,
    (Vertical Length) = V, (Weight) = W, (Horizontal Distance) = H & (Tension) = T
    H2/V2 (W2) = T; H/V (W) = T; L/V (W) = T; D2/L (W) = T
    512) What is the minimum safety factor for overhead lifting?
    513) What is this a equation for? (Rigging Strength x Strength Reduction Factor) (Safety Factor x Load Increase Factor)
    514) Federal and state occupational safety and health laws require that any employee in danger of falling more than 6' be protected from falling, so fall protection is required whenever people are on rigged equipment higher than this (stage hands on lighting trusses) for example. If their hoists are used to support people and the fall protection systems, what should the hoist load capacity be derated to? 1) Hoists already have a safety factor for this built into them, and do not have to be derated for intermittent use; 2) 75% Capacity; 3) 60% ; or 4) 50%
    515) Static loading of any hoist should not exceed how much of its capacity?
    516) Whenever a load is picked up, stopped, moved or swung, there is an increased force due to dynamic loading. The more rapidly or suddenly such actions occur, the greater this increase will be. In extreme cases, the force put on the rope may be two, three, or even more times the normal load involved. How is SWL of a rope designed to reflect this?
    517) What agency is in charged with enforcing rigging safety?
    518) When rigging, you choose the safety factor, calculate the allowable load than try to stay how much below it?
    519) What is the SWL of ½” wire rope slings?
    520) When using a shackle on a wire rope sling, besides SWLs matching up, what other factor should be considered in choosing a shackle to fit within the thimble opening?
    521) When using a basket hitch, why is it necessary to use a shackle on one of the ends attached to the main shackle, and where on the shackle should it be installed, towards or away from the eyelet of the pin?
    522) A basket hitch will hold how much weight above the SWL of the sling itself?
    523) What is a split basket hitch and what is it used for?
    524) What kind of a knot should you tie to equipment at the bottom of a drop line?
    525) What is a pear ring used for?
    526) When installing a roundsling on the pin of a shackle, what should you do to the sling to prevent the sling from twisting and un-screwing the pin? What would be a better way of hooking this connection up when possible?
    527) How many shackles can be safely loaded on the hook to a chain hoist?
    528) Why should you only hook two equal length bridles to each shackle?
    529) How many layers of normal thickness burlap bag should be used to protect the corners of a beam?
    530) When hooking up to a truss, why do you not hang from the top chords?
    531) When hooking up to a truss, why do you have to wrap around junctions (panel points) and not points between panel points of the tubing?
    532) When possible, why do you wrap slings around the parameter of a truss and not go through the center?
    533) What is the minimum angle of a basket hitch tied around a truss to the pickup point shackle?
    534) Why is a low head-room truss bracket OK for a truss layout with angles or boxes, but not Ok for a single span or length of truss?
    535) What is the SWL and use of Stac Chains (Deck Chains) How many bends are they allowed?
    536) Under current industry practice, Block and Falls with hooks are safe and usable 1) only with latches, with shackles, or either way?
    537) What type of drop forged Eye-Bolt is the only type to be used for angular lifting?
    538) What is the a strength loss to webbing & roundslings when wet, and what is the maximum operating temperature? 5% /130°; 10% /165°; 15% /180°; or 25% /210°
    539) What is this the formula to? Force = (Weight) x [(Free Fall Distance/Stopping distance) +1]
    540) If a rigging point fails, the dynamic load can be as much as ____ times the falling load, redundant points make up for this by carrying and distributing this load as much as possible under a safety factor of ____ when possible, for _____ times the original static load. (3 or 5; 10 or 12; 30 or 60)
    541) Safeties for rigging should be (with a slight tension, or slightly slack)?
    542) A 250# man wearing a safety harness with lanyard falls 6'. As he stops, the harness and lanyard stretch 6". What is the force on him and the rigging supporting him? If he has a shock absorber lanyard that extends 2' as it stops him, what will be the force? What if the shock absorber extends 42"?
    543) Find the length of wire ropes, and the tension on them: (note: the load is evenly distributed)
    Two diagonal support cables have a horizontal distance from rig point to truss of 5' and a vertical distance of 10'. Truss weight or static load is 4,000 pounds. What is the SWL weight of the cable?
    Note: Diagonal Force = (Diagonal Length ÷ Vertical Length) x (Vertical Force)
    544) If a center pickup point were installed vertically on this truss, what would the new figures be?
    545) For dead hangs, try to keep the applied load at least 20 to 25% under the cable’s allowable load. If you do then: Dead hangs of ___ degrees off vertical are OK, without calculations needed. (Force increase of 15 degrees or less) Dead hangs between ___ and ___ degrees off vertical are possible, but must be calculated. Dead hangs more than ___ degrees off vertical should be avoided.Since most dead hangs are within ___ degrees of vertical, this rule given the safety factor and safety margin eliminates the need for most dead hang calculations given the SWL of the cable is known.
    546) An electrician wants to lift a 600# dimmer board that is 8' long. He wraps it once around tightly with ½" manilla rope, ties a square knot, and puts a chain hoist hook on the rope at the center. The rope stretches 12", so there is some gap between the board and the hook. What is the tension on the rope? If wrapped around twice would it be any safer?
    A square knot is about 40-45% efficient. The bend on the box corner cuts the rope capacity to about 75% of its original strength. Given the above formula, and the rope’s tag rating of 2650#, is this safe?
    547) What is this equation? Distance x Force = 2 feet x 50# = 100 ft-lbs.
    548) What is the load distribution weight of a 1,000# truss 40' long when the first hoist is placed at one end and the second is placed 10' from the other end?
    549) A 40' truss has an evenly distributed load of 800#, in addition to this, it has a 1,000# point load 10' from one end. What is the load on each lifting point if the first one is 10' from the end, the second one is in the center, and the third one is at the end of the truss?
    550) What are the loads on the two pickup points of a 48' truss that weighs 1782#, and has a point load 10' from the second end of 1129#?
    [Load = (Span between Center of gravity or point load location and lifting point ÷ Total span) x (Weight)]
    551) A weight on the end of a cantilever causes a load on the near support that is bigger than the weight itself. Lifting load at the closest point = distance between point load at the end of cantilever and the next closest support distance times the weight at the end of the cantilever. If rigging loads of a cantilever load are undesirable, what two things can be done to the first support to relieve this situation, given the first point closest to the load cannot change? Note: both answers involve a change in one part of the formula above and no ghost or phantom loads on the opposite end.

    552) A beam has 4 supports, evenly spaced and with an even distribution of load. The total load is 2638# what is the load on each support using the intuition method and actual load method?
    553) In what case would you use the intuition method for figuring load verses actual multi-point load distribution? Note: Intuitive multi-point load distribution assumes that on a straight level uniformly loaded beam supported at multiple evenly spaced points our intuition assumes that each support holds up half the weight of the beam sections hanging from it. Why is this different from how real load works?

    554) The rule of thumb method assumes that with four or more points, the biggest difference on any point between intuition and good mathematics is 14% of section weight, defined as (X). This can be handled by making sure the rigging for each point can support 14% more than the intuition predicts, so assume all interior loads weigh 1.14X. With a three-point beam, the difference on the center point is 25%, so the center point rigging should support 25% more than intuition predicts it will weigh. End point loads are always under what intuition predicts, so don’t add anything to them beyond the intuitive answer. What is the rule of thumb load distribution for a evenly distributed load of 1,000# between 4 points with a point load of 200# three quarters of the way to support number three?
    555) A 120' long truss is supported by 4 hoists evenly spaced every 40', numbered L1, L2, L3, and L4. The truss, lights, and cable together weigh 6,000#. The lights and cable are more-or-less evenly distributed, and the is a cable pick hoist that supports the weight of the multi-cable coming off the truss. There is also a point load of 1,000# 30' from L1. What are the loads on each hoist?
    556) Truss supported by and raised and lowered by chain hoists pose certain problems when raising truss and other equipment, depending on their individual speeds amongst other things the weight of a truss can vary by how much at each support given a three motor truss?
    557) How would a 20' x 20' square of truss differ in how loading was figured from a straight line 800' supported by the same number of hoists?

    558) When using a four point bridle to support a box or square truss supported by the corners, you must design each corner to be able to support how much of the total weight? Why?

    559) What is the difference in design loading for short term temporary rigging, with experts doing the rigging verses permanent installs with unknown personnel operating the equipment in the future?

    560) The clutch on a chain hoist is designed to slip at approximately what percentage of its capacity?
    561) Point loads at the center of an evenly supported truss with six points will approximately have how much added or subtracted weight on each member in reality due to the built-in flexibility of truss or pipe given the center will receive 70-80% of the actual point load?
    562) How would a point load on a 7 point truss be given the load directly under the center load?

    563) Why are trusses designed with flexibility or deflection in mind in relation to the flexibility of the buildings they are hung from?

    564) If there is a cable drop off the end of a truss, it gets heavier as the truss rises and what?


    565) An object hung on angled deadhangs rises more or the same as the length of the wire that runs into the hoist? On a 9 point suspension, of a box supported by two corners and the center on a vertical hang, and the rest diagonally what will be the solution to raising it?

    566) Using the 3 to 1 rule, how much trim height can you get at a minimum on a 10' distance between beams to a point between them given a 12" truss and a 8" beam? What would be the span on the 90° rule.
    567) On the 3 to 1 rule, a 1 foot change in the length of one leg makes how much of a change in the junction position?
    568) The flatter the bridle angle the ___ the juxtaposition of the hanging point when moved.
    569) What is this a formula for?
    (W = Weight, L = Diagonal Length, H = Horizontal Length, V = Vertical Length)
    Tension1 = W x L1 x H2 T2 = W x L2 x H1
    V1 x H2 + V2 x H1 V1 x H2 + V2 x H1
    Tension on the first leg decreases with length, as Tension increases on the second leg with length.
    570) What is the full-load amperage of our ½ and 1 ton chain hoists?
     
  2. ricc0luke

    ricc0luke Active Member

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    ship... you have almost 200 questions here... and you keep posting lists of questions different forums about differnet stuff... just out of curiosity, what is up with this sudden burst of quizing? well... i'm tired... but i'll have answers for this tomarrow night.
     
  3. kingfisher1

    kingfisher1 Active Member

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    for question 432: is that ideal mechanical advantage or real world mechanical advantage?

    Actual Mechanical Advantage (A.M.A.)=resitance Force (force out)/Effort Force (force in)

    Ideal Mecanical Advandage= Effort force/Resitance Force
    and if were going to talk about simple machines then we have to talk about effeciency;

    Eff.=Work out/Work in=Force out x Distance out/ Force in x Distance in
     
  4. ricc0luke

    ricc0luke Active Member

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    ship: here i just my first round of answers... but it is 10 after 3am and i really need some sleep tonight because i am working on a how tomarrow, unfortunaly the bussiness end so i'm gonna actually need half a brain... like i said just the first round... let me know how i'm doing please...




    400) What is the maximum safe working load of 1/8" galvanized wire rope?
    1/8” GAC braking point is 2000lbs. The SWL is 150lbs.

    401) What is the approximate safe working load of a safety cable?
    This question is wrong right from the start. You don’t ever need to know how much weight you can safely apply to a safety cable. The only thing you need to be worried about with safety cables is shock-loads. The method of calculating shock loads I have if anyone wants it, but frankly it’s a waste of time.

    402) What is the difference in SWL between a double saddle cable clamp and a malleable clamp?
    A double and single saddle forged wire rope clamps are about 80% efficient when applied and torqued properly. A mallable clamp is only about 60% efficient.

    403) What is the percent efficiency of a drop forged wire rope clamp?
    80%.

    404) What is the percent efficiency of a aluminum Nicopress sleeve and why are they not to be used on stage?
    They are only 50% efficient.

    405) What is the difference between SWLs for stage work and industry?
    The SWL’s for the entertainment industry in general, epecially live theatre, have a greater safety factor because they are almost always used in overhead lifting and are always near many people who aren’t in hardhats or other protective material should something go wrong.

    408) What is the Safe Working load of a 1200# SWL Rope with a Clove Hitch in it?
    A clove hitch is about 75% efficient leaving you with a SWL of 900lbs.

    409) What is Schedule 80 pipe?
    Schedule 80 pipe is very similar to Schedule 40 only having walls alittle more than 70% thicker. The difference in the wall thickness is compensated for with the inside diameter, meaning that the outside diameter of Schedule 40 and 80 are the same.

    412) What is the approximate bolt grade of Aircraft Grade Alloy Bolts?
    Grade 8

    419) A Sling lifting 1,000 pounds is attached so to its load so it forms a 45/45/90° triangle between its two hanging points and the hook, what is the approximate load on each diagonal leg of the sling?
    VECTORS! 700lbs of tension on each leg.

    420) In general when hanging things, the steeper the vertical angle of the cable from the hanging point, the ______ the load is on the cable.
    Lesser

    424) What does “Never Saddle a Dead Horse” mean?
    When applying a wire rope clip, the saddle always goes on the live end of the cable. The reason double saddle clamps are preferable is that they are impossible to be put on backwards and that they do not damage the wire rope as much.

    425) What are Legs, Boarders, Teasers and Tormenters, which is which and what if anything is the differences between the two general styles of drape?
    Teasers (aka Borders) are short curtains, 4’ to 10’ that extend the full width of the stage and into each wing. They are placed at intervals from DS to US and prevent the audience from seeing material in the fly space. They limit the upward sightline. Legs (aka Tormenters) are curtains on each side of the stage that extend into the wings and mask the wings from audience view. They are normally placed on the next available batten after the teasers.

    430) What is a fire link, what is its load rating, and how long of a service life does it have?
    A fire link is a mallable piece of metal in the trip wire of fire curtains. There are normally several placed in various intervals along the wire. The extream heat of a fire will cause the metal to become flexible enough to separate under the tension of the wire and cause the curtain to fall. They should be replaced every 2 years. The load rating various on the particular alloy used.

    431) What is Static Equilibrium in reference to a fly system?
    Static Equilibrium refers to the condition a fly system when all forces are equal (no net force) and nothing is in motion.

    436) What is a knuckle buster and what is it used for?
    A knuckle buster is a clamp that is sometimes used to mark a trim on a line set. They are called knuckle busters because of the pain they inflict when you hit it while operating a line set.

    441) On a beam, batten or truss with three evenly spaced supports on each end and the center, what is the percentage of load carried by the center and each end?
    The load applied to the center support would be approximently half the weight of the beam. Each end would support approx. one quarter of the weight of the beam. The distrubution of any additional weight applied to the beam depends upon where it is applied.

    442) In general, moving the end supports toward the center of a load does what to the percentage of the load carried?
    It will increase the amount of the load they carry. (If this is a continuation of #421 then it would also decrease load on the center support)

    443) On a five lineset or post supported beam/truss/batten, which post(s) carries the most weight?
    With only the bar weight, the three interior lines would each support equal amounts of weight.

    444) Grid floors have their deck planks/steel mounted parallel or perpendicular to the
    proscenium?
    Parallel to the proscenium, perpendicular to the supporting steel.

    449) On a double-purchase counterweight system, how many feet does the batten travel for every 1' of arbor travel, and how many pounds of counterweight are required for every pound of load?
    On a double-purchase counterweight set, rope travel is equal to pipe travel. 2’ of rope (or pipe) will move the arbor 1’. You must add twice the weight of the pipe to the arbor on a double-purchase system.

    452) Wire ropes with more strands have better fatigue resistance, but for the most part less strength, what is one other advantage cable with more strands?
    It is more flexible.

    453) When installing a new wire rope, it should be taken off the spool so that the major bending is in the same or opposite direction as it was on the spool?
    Same.

    462) On a trim chain with 1.1/2 wraps around the pipe, how do you attach the two ends of the chain to double the weight capacity of the trim chain?
    Each end of the trim chain should be attached directly to the lift line.

    463) Why should you not use regular steel chain on a fly system?
    It is not rated for overhead lifting.

    464) New trim chain comes with snap hooks/dog snaps, by current standards what is the purpose of it, and should you use a quick link, lap link, shackle, or grade 5 bolt to replace the snap hook? Why?
    Snap hooks should never be used for rigging. A quick link is some times acceptable, but generally not on any rigging that isn’t static. A grade 5 bolt is acceptable, though a forges shackle is the best option.

    466) On a batten, when a clove hitch is applied with wire rope clips above it, what is the efficiency of the attachment?
    75%

    469) Wire guide arbors are used for fly systems with grid heights under how many feet?
    Under 25ft is the standard except in special cases where a track system is not practical. The line sets should be spaced further apart on those higher system to allow for the arbor to swing.

    474) What is the proper order to install the crimps on a 1/8" nico sleeve and how many are required?
    2 crimps are required, first crimp should be away from the thimble.

    476) What grade of bolt is used for most general purpose rigging applications?
    Grade 5
     
  5. ship

    ship Senior Team Emeritus Premium Member

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    Tag, you are it for the next round of questions.

    400) 280 is what I have always heard but 150 is safe given this. What are you using for a ratio for it, and what type of wire rope are you basing this breaking strength upon?

    401) Correct a safety cable is designed for shock loading and not for static loading. Given wire rope with too small a bending radius around a snap hook, a lack of thimbles and a snap hook if even in general load rated and traceable, it’s nowhere near what is often loaded upon it in hanging with a safety factor. As a question, it would be one of the snap hook verses the too small bending radius otherwise in SWL of the safety cable.

    402) Correct.
    403) Correct - as long as someone has not started losing screws on it and replacing them for store bought ones.
    404) Correct and not designed for shock loading.
    405) Correct but I was looking for like a 5:1 to 10:1 ratio difference.
    408) Check your figures on this knot.
    409) Very impressive.
    412) At least grade 8 if not up to grade 10.
    419) I forget the figures in not doing that stuff for a living any longer.
    420) Correct.
    424) Which end to you mean by the live end? (You know and I know but it’s probably not well described.)
    425) Is there a difference between the terms for each?
    430) Every 2 years?
    431) ....
    436) .... :)
    441) Good point on the loading, but as I remember not correct for a standard distributed load. Could be if the points were spaced just so on the other hand I suppose.
    442) Correct
    443) I don’t remember this to be correct.
    444) ....
    449) ....
    452) ....
    453) I have forgotten this rule so cannot respond without looking it up.
    462) ....
    463) ....
    464) This question should be explored more - past discussion on stagecraft and in “Stage Rigging Handbook” do not agree with all or some or most of your answer. On the whole you are correct but not in many ways by way of answer.
    466) This given 408 is correct than would also be correct. If not, one might have a wee problem.
    469) The height keeps getting shorter but for the most part is a good figure for the use.
    474) Two crimps?
    476) Correct for most applications.
     
  6. ricc0luke

    ricc0luke Active Member

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    For #408 and #466, I checked the Stage Rigging Handbook... it says that a clove is 75% efficent, a clove with 2 half hitches is 65% effective.

    For #441 you are correct in that if a load was evenly distrubuited upon the entire lenght of the batton the ratio would still be the same, but if the load was not evenly distrubuited along the entire lenght of the batten it depends upon where exactly the load is located. Also that ratio should be more like 30-40-30 instead of 25-50-25 since the batten most often time extends past the last lift line on each end, and if it didn't, it would really be .1875 - .6250 - .1875

    #469 should be 35 feet, I goofed that up.

    #430 I can't remember where I read that but I know I did... can't find it now... I remember it saything that the alloy being so soft can strech out under the tension... Maybe that was just how often they need to be inspected... I haven't been able to find any creditable info on fusable links for fire curtains.

    #425... well... some people will say that the tormentor and the teaser are hard and are used to shape the proscenium and that all the curtains would be borders and legs...

    #474... Actually you can do it with 1 crimp if you have the right tool... here's a chart by JR Clancy showing which tools with which sleeves and how many crimps... I'm guessing you were looking for 3, when I did it I was doing 2.

    http://www.jrclancy.com/Downloads/Nicopress Sleeves 050610.pdf

    #443... I looked this up, its the two inner lift lines but not the center. 0.0980 - 0.2860 - 0.2320 - 0.2860 - 0.0980

    #424... Live end = The side of the cable which directly supports weight.

    #464... I would love to hear your thinking on this one ship. I mean yes there are some snap-hooks that are weight rated, but they cost a fortune and are really only practical for things such as clipping harnesses quickly when flying people... I would always just stick with a shackle when static rigging and linesets... A grade 5 bolt isn't a bad backup, but I wouldn't use it alone.

    #400... I have also heard 280. It depends on who it is telling you. Me personally, I don't make the stuff, I'll go with the lower of the 2 SWL's just for alittle extra safety. But yea, when I think about it, 280 sounds right with a breaking strength of 2000lbs.

    ---------------------------------------------------
    I have to say that as I am still plunking away at these other questions yet that I am surprised there are a few that you haven't asked... Like what we use 7x7 GAC for and why over 7x19 GAC.
     
  7. ship

    ship Senior Team Emeritus Premium Member

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    Excellent and 100% in agreement or 99.9% in agreement with all refinements especially to that which I remember less specifically than you do. "Work Smart Not Hard" you say, I say "If You Can't Truck It, [email protected]& It." Same meaning in intent and concept for life. Your knowing what I'm thinking for a correct answer but support of your own answer speaks well of your experience and knowledge. Something I would trust on your stage even if I would continue to destroy all Nicopress safety cables I find with two crimps that follow the show home.

    On trim chains, they normally come rated as a unit for 1,000# SWL from most sources to which in the past I have looked at the often cast dog clip "snap hook" connection or lack of schedule what ever chain and scratched my head. I like bolts but would not use them for fastening either. This as other than a safety when the snap hook fails. In the past when I installed rigging systems, this trim chain was the least rated component as a definate problem. On a trim chain, long links are very usefule for doing shackles yet they are not rated for lift. Recently bought some Sch. 80 overhead lift chain and it was very difficult to use with similar sized shackles - this especially of the domestic Chicago brand. Bill Sapsis recently on Stagecraft mentioned Sch. 40 chain which while not overhead lift is a better solution even if not long link as still useful. Can't exactually do a deck chain for a trim cain either.

    I'm thinking that a batten clamp with chain is the best solution in adjustable solutions. That's what I'm stinking at least.
     
  8. Radman

    Radman Well-Known Member

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    400) What is the maximum safe working load of 1/8" galvanized wire rope?

    with a 2000# breaking strength and 1:10 safety factor, I get 200#


    401) What is the approximate safe working load of a safety cable?

    Does it matter? Safety cables should never be used to support a load. I often see speakers hung by safety cables, and I don't like it one bit.


    403) What is the percent efficiency of a drop forged wire rope clamp?

    80%


    404) What is the percent efficiency of a aluminum Nicopress sleeve and why are they not to be used on stage?

    50%, can't be used for live loads


    405) What is the difference between SWLs for stage work and industry?

    1:5 safety for industry, 1:10 for stage


    406) What is the safe working load of a single spanset in the choker arrangement around 1x1 truss?

    Aren't slings available in a multitude of ratings? At any rate it should be shown on the label.


    410)Which pipe is not measured the same as the rest of the pipe: Schedule 40 black pipe, PVC, Pneumatic, EMT, RMT, Aluminum, Galvanized, or Schedule 80?

    pneumatic


    415) What is the purpose of washers in high strength fastening?

    To distribute the load across a larger surface area on the bolted material.


    419) A Sling lifting 1,000 pounds is attached so to its load so it forms a 45/45/90° triangle between its two hanging points and the hook, what is the approximate load on each diagonal leg of the sling?

    71%, so... 710#


    420) In general when hanging things, the steeper the vertical angle of the cable from the hanging point, the ______ the load is on the cable.

    lower


    421) The proper way to un-reel wire rope or cable from the spool is from above or below?

    I think above...


    422) In coiling a right-lay cable, wire, or rope, the proper direction to coil is clockwise or counterclockwise?

    Clockwise(?)


    423) How do you “Mouse off” a shackle or turnbuckle?

    Prevent it from unscrewing, usually by a small wire or zip-tie passed through the small hole in the screw pin and the bell(term?) on a screw pin anchor shackle.


    424) What does “Never Saddle a Dead Horse” mean?

    Never put the saddle of a wire rope clip on the dead end (end without load) because the u-bolt can pinch and damage the wire, which you don't want to do the live end (end under load) for obvious reasons.


    425) What are Legs, Boarders, Teasers and Tormenters, which is which and what if anything is the differences between the two general styles of drape?

    Well, I know legs are tall narrow drapes used to mask on the side, and borders are wide shorter drapes for masking the top, but I don't know about torms and teasers.


    426) What is stronger in rigging components, bent stamped steel, cast steel plate, or forged steel?

    I'm pretty sure forged steel is strongest.


    430) What is a fire link, what is its load rating, and how long of a service life does it have?

    A fire link is a device which melts when there is a fire, releasing the load (usually a fire curtain or fire door.) I think they come in different ratings, but I doubt they can sustain much of a load. I don't know about their lifespan.


    431) What is Static Equilibrium in reference to a fly system?

    When everything is balanced while in a state of zero motion.


    432) Mechanical advantage is what divided by applied force?

    Recieved force (wrong term I think, but you get the idea).


    433) What does the head block of a fly system do?

    Essentially it is a bunch of pulleys in one block, usually used to direct the lines from across the stage for one batten down to the counterweight.


    434) What knot do you use to tie off a hemp lineset to a batten?

    Clove hitch (I think with usually one or maybe two half hitches)


    435) What is the cable called a Sunday and what is it used for?

    Ha, I made a bunch of those a few months ago. They are short loops of wire used for temporarily attaching weight to a lineset. It is choked around the line (or lines) and weight is hooked onto the loop. Generally the wire has to be pretty small diameter. Works pretty well, actually.


    436) What is a knuckle buster and what is it used for?

    A little clamp that attaches to the handline as a reference for trim heights.


    437) Rope must be strong enough to support the load safely and absorb what three loadings for any particular application?

    Shock, impact, and peak. (?)


    447) What is the difference between an Idler Pulley and a Mule Block?

    Idler pulley is a little pulley to prevent the slack in a line from touching the gridiron. A mule block is used to change the direction of the line.


    448) How do you tie off a line set to a pin rail?

    I don't know the name, but it's around the bottom, cross over, around the top, cross over, around the bottom, loop over the top and pull it tight. I could draw a picture.


    449) On a double-purchase counterweight system, how many feet does the batten travel for every 1' of arbor travel, and how many pounds of counterweight are required for every pound of load?

    Double, so 2', 2#.


    452) Wire ropes with more strands have better fatigue resistance, but for the most part less strength, what is one other advantage cable with more strands?

    Flexibility.


    453) When installing a new wire rope, it should be taken off the spool so that the major bending is in the same or opposite direction as it was on the spool?

    Same.


    458) What would be the advantage besides smaller bending radius, of using fiber core cable over solid or stranded core wire rope?

    Weight.


    462) On a trim chain with 1.1/2 wraps around the pipe, how do you attach the two ends of the chain to double the weight capacity of the trim chain?

    Each end link seperately to the next peice of hardware in the line.


    463) Why should you not use regular steel chain on a fly system?

    Not rated for lifting.


    464) New trim chain comes with snap hooks/dog snaps, by current standards what is the purpose of it, and should you use a quick link, lap link, shackle, or grade 5 bolt to replace the snap hook? Why?

    I don't think there is a purpose other than perhaps to link the chains for transport. Depending on the application I'd replace it with a shackle or quick link.


    465) How do you tie a circus knot, and what is it used for?

    Take about 2'-3' from the end of the line and tie a clove hitch. Lock it and wrap the dead end 4 times up the live end, then 3 times back down to the knot. Pass the dead end through the resulting loop at the cross of the clove, and if desired again through the loop where you switched directions while wrapping around the live end. You may also optionally wrap with tape.

    This knot is often used for guy wires or other temporary attachments where it would be too expensive, excessive, or time consuming to use nico press sleeves or clips. In a previous post you stated it has 100% effeciency.


    466) On a batten, when a clove hitch is applied with wire rope clips above it, what is the efficiency of the attachment?

    I would think between 80% and 100%.


    470) Why are donut arbors frowned upon?

    Because baked goods have no business posing as rigging hardware.


    472) What is the correct order to install 3 wire rope clips after a thimble?

    Furthest, closets, middle (from the thimble).


    473) What is the proper torque to apply to 1/8" wire rope clips and what size nut is it?

    4.5 ft-lbs, I think like 1/4" or 3/16" nut. I forget.


    478) A wire broken under a tensile load that exceeds its strength is recognized by the “cup or cone configuration at the fracture point, coned break points indicate what?

    The wire failed while still ductile.


    485) What are two ways to ensure a screw pin shackle will not un-screw? What other types of shackle are available?

    Mousing, loctite. Round pin, bolt type, chain shackles...


    486) What should you do when two or more Spanset ends are to be installed on a chain hoist hook?

    Pear ring and two shackles.


    488) What is the standard length of a new Schedule 40 pipe from a plumbing supplier?

    I think 8'.


    Break time.
     
  9. ship

    ship Senior Team Emeritus Premium Member

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    410) incorrect
    415) correct but also what in tightening it?
    421) incorrect
    422) Don’t remember.
    426) Incorrect
    465) 80% and 8-10 turns each way.
    470) “Donut” arbors are a reality in older houses.
    488) Plumbing/steel supplier not hardware store.
     
  10. Radman

    Radman Well-Known Member

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    410) Guessed.
    415) Also helps with the rotation of the nut/bolt on irregular surfaces to allow complete tightening.
    421) Below.
    422) Well that's not very helpful :(
    426) Damn.
    465) Guess I was just taught wrong.
    470)
    488) Oh. Not a clue.
     
  11. ship

    ship Senior Team Emeritus Premium Member

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    Think tightning but more ball bearing and friction than irregular surfaces which would cause problems due to angle.
     
  12. ricc0luke

    ricc0luke Active Member

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    for #410 ship... is it Aluminum?

    That's just a guess though... I promise I'll get my other answers posted tomarrow... I have them sitting here in a word document...
     
  13. Radman

    Radman Well-Known Member

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    415) I'm thinking then helps prevent rotation of botled material from loosening the nut.
     
  14. ricc0luke

    ricc0luke Active Member

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    No, think about that... the washer will turn with teh bolted material because of the amount of friction there would be... a wash isn't going to help any with rotation... they had it right before with the distrubuiting the force across a greater area and irregular surfaces
     
  15. ricc0luke

    ricc0luke Active Member

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    sorry... I completely forgot to post this last night so here it is...

    TAG your it now ship!

    407) What is the approximate sheer strength of a store bought 5/16" lag bolt?
    Umm… you know what… I don’t know that one… I know that once I saw 4 dry wall screws shear off because some idiot didn’t use lags. Then they redid it with lags… and the 2x6 eventually split into a few pieces… so then they sent it out in stage with globs of polyurethane glue and c-clamps on it…
    So ship, where do you come up with the shear strength for a lag?

    411) What is the difference between 1/4" NPT, 1/4" NF, and 1/4" NC nuts?
    It’s the type of threading. NPT: National Pitch Threading NF: National Fine NC: National Course
    Though I’ve heard it as UNC, UNF, UNEF.

    416) Is there a difference in strength between zinc and plain steel fasteners?
    The zinc won’t rust.

    421) The proper way to un-reel wire rope or cable from the spool is from above or below?
    Below.

    422) In coiling a right-lay cable, wire, or rope, the proper direction to coil is clockwise or counterclockwise?
    Clockwise.

    423) How do you “Mouse off” a shackle or turnbuckle?
    SEE #467

    426) What is stronger in rigging components, bent stamped steel, cast steel plate, or forged steel?
    Forged steel.

    433) What does the head block of a fly system do?
    You and I both know darn well what a head block does… now… how to explain it… It is the first pully in a counterweight system that supports the weight of all of the lift lines… Umm… much easily explained with a picture.

    434) What knot do you use to tie off a hemp lineset to a batten?
    Clove with 2 half hitches.

    435) What is the cable called a Sunday and what is it used for?
    A Sunday is a loop about 5 feet in circumfrence used to attach sandbags or other weights to lift lines, trim line, or an arbor.

    437) Rope must be strong enough to support the load safely and absorb what three loadings for any particular application?
    Dynamic, static, and shock?

    439) A the groove of a sheave should be sized to support at least how much of a ropes circumference?
    1/3 the rope’s circumfrence.

    440) Explain resultant forces applied on a block.
    Anytime a rope changes direction there are 2 forces at 2 different angles. These 2 forces acting together form the resultant force. Ex. A rope passes over a sheeve making a 90 degree angle with a load of 1000lbs. The resultant force is about 1400lbs at 45 degrees.

    445) What is fleet angle, and how much is permissible?
    The angle of the difference between two blocks. 1.5 degrees.

    447) What is the difference between an Idler Pulley and a Mule Block?
    A idler pulley simply supports the lift line to prevent it from sagging as much between the block and the head block. A mule block is used to move the lift line horizontally when it cannot be placed in a straight line with the headblock.

    448) How do you tie off a line set to a pin rail?
    By a process called belaying
    1- Go infront of the rail down around the back of the bottom of the pin then come back up and cross the rope over the first pass and go around the top of the pin and come back on the inside of the first pass. 2- Go down around the bottom again crossing the second pass. 3- Come back up straight up going on the outside of the first pass and put a half hitch around the top of the pin with the excess rope coming out the bottom of the hitch and pull tight...

    457) What does 6x37 IWRC stand for?
    There are 6 wire ropes with 36 to 49 strands in each winding around an independent wire-rope core.

    458) What would be the advantage besides smaller bending radius, of using fiber core cable over solid or stranded core wire rope?
    More flexible?

    459) For what two reasons is galvanized wire rope the standard cable for the industry over stainless steel?
    Stainless steel is not as strong as the galvanized and is more expensive. It should only be used where corrosion is an issue.

    460) What are the differences between rotation resistant wire rope and sash cord wire ropes?
    Rotation resistant wire ropes core twists in the opposite direction of the outer wires to counteract the rotation force. Sash cord is weak wire originally intended for use on window sashes.

    461) Which type of wire rope is weakest and strongest, Bright Sash, Tiller Rope, Plow Steel, or Galvanized Wire Rope?
    The weakest is bright sash. The strongest would be GAC

    467) When using turnbuckles on a fly system what is required to be done to them to make them safe?
    To make a turnbuckle safe for overhead rigging you need to prevent it from being able to close, but especially open on it’s own. Jam nuts will prevent it from closing, but you prevent it from opening, you should put No. 12 solid core wire through the ends of the eye’s shanks, or use wire mousing to keep it from opening further

    471) Spreader bars should be used every how many feet on a counterweight arbor?
    At least every 3’. It should be 12 gauge steel.

    472) What is the correct order to install 3 wire rope clips after a thimble?
    Furthest from the thimble, closest to the thimble, last but not least, the middle.

    473) What is the proper torque to apply to 1/8" wire rope clips and what size nut is it?
    4.5ft-lbs

    475) What is the reason not to re-use nuts to bolts for purposes of rigging?
    It is important to use original bolts because they are not stamped with any sort of identification and could easy be mistaken for a lesser quality nut.

    483) What is the minimum lifting angle to the center plane on a drop forged shoulder verses normal eyebolt?
    90 degrees?

    484) Properly reeved splices in rope are considered to be how efficient?
    A long splice is 85% efficient.

    485) What are two ways to ensure a screw pin shackle will not un-screw? What other types of shackle are available?
    Mousing, Teflon tape. Shackles with pins instead of a screw. (I forget the term. )

    486) What should you do when two or more Spanset ends are to be installed on a chain hoist hook?
    Use a pear ring.

    488) What is the standard length of a new Schedule 40 pipe from a plumbing supplier?
    Kinda a guess… 20’?

    489) What is the difference between the main and the grand drape?
    The main drape is mot often time a traveler (sometimes called the act curtain), is located at the front of the stage and hides the tage from audience view. The grand drape is very similar to a teaser and is located just infront of the main drape.

    490) What is an Olio and how is it different from show drops?
    An Olio is a mid-stage curtain. It is different from show drops in that it is normally not black but a lighter color. It is often times only found in venue that also serve as a lecture hall on a regular basis.

    493) Where is the plaster line on stage?
    The back of the proscenium arch.

    494) What is the purpose of a Tab Drape?
    It’s just another kind of drape unless you are referring to a contoured?

    495) What is a purchase line?
    A purchase line is the actual hand line in rigging.

    496) How are tableu or tabs rigged differently than pleated drapes?
    Instead of being pulled together horizontally, they are pulled together vertically. A contoured tableau curtain is one of the coolest curtains I have ever seen. Especially once I saw one made of shear fabric.

    497) To ensure fullness, how should you hang a drape?
    Fullness is normally sewn into drapery. All you have to do it tie the eyelets up pulled relatively tight.

    498) When hanging drapes how many eyelets of over lap should there be between seems?
    2ft?

    500) How do you go about bouncing the main?
    You allow the momentem of the lineset to ‘burry’ the main in the floor. Then, the difference in weight when the curtain is resting on the floor will cause the curtain to rise on its own. You should stop it jut before it is about to lift off the ground.

    501) When lowering a drop, electric, or other scenery on a fly system, where should your primary attention and eyes be directed?
    Your eyes should be focused on the line of travel of the batten.

    502) How many lights can be pulled off an electric before it should be re-weighted?
    This is entirely dependant upon your own rigging equipment, how you operate it, and also the weight of the lights in question.

    506) Why shouldn’t you operate or store a chain-hoist on its side? (2 reasons)
    It has to do with gears and oil and not having the slightest bit of tension on it…

    507) What is the maximum load rating of a Genie ST-24 Super Tower?
    Genie ST-20 Super Tower = 800lbs
    Genie ST-25 Super Tower = 650lbs
    I’ve seen the Genie ST-24 Super Towers, but I don’t know the rating off the top of my head.

    512) What is the minimum safety factor for overhead lifting?
    Well the standard safety factor in theatre is 8:1, but I know a professional rigging company that flys people with a safety factor of 5:1

    518) When rigging, you choose the safety factor, calculate the allowable load than try to stay how much below it?
    I stay under 75%.

    525) What is a pear ring used for?
    To attach several lines or shackles to a hoist.

    527) How many shackles can be safely loaded on the hook to a chain hoist?
    2

    528) Why should you only hook two equal length bridles to each shackle?
    To prevent the forces on each bridal from being horribly out of balance.

    535) What is the SWL and use of Stac Chains (Deck Chains) How many bends are they allowed?
    Deck chains are not to be used for overhead lifting. I doubt you would consider using them for anything else in a theatre so I am not even bothering looking this one up.

    539) What is this the formula to? Force = (Weight) x [(Free Fall Distance/Stopping distance) +1]
    Simple version for shock loads.

    541) Safeties for rigging should be (with a slight tension, or slightly slack)?
    Slight tension

    564) If there is a cable drop off the end of a truss, it gets heavier as the truss rises and what?
    Lighter as it falls?
     
  16. ship

    ship Senior Team Emeritus Premium Member

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    Correct
    Aluminum is commonly a structural pipe and is measured by it's outside dia. and thickness. The rest have material inside or flowing thru it so it's measured by a "nominal" inside dia.

    This gets to be very important when using both 2" OD, 1/8" wall aluminum pipe and also 1.1/2" Sch. 40 pipe.
     
  17. ship

    ship Senior Team Emeritus Premium Member

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    Wouldn't that be the description of a lock washer?
     
  18. ship

    ship Senior Team Emeritus Premium Member

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    Very Impressive!!!

    I’m not checking a lot of your answers for detail such as 1.5 degrees angle on 445 - believe your decimal point is in the wrong place or it was a crumb ? Also in 439, the groove in a sheave only 1/3 the circumfrence??? But you could be correct and I wrong. (Knew I should have listed the answers when I wrote out the questions a few years back. Dooh!)

    407) The sheer strength of a lag bolt is it’s stock dia. in this case 5/16" and it’s bolt grade in this case grade 2. There is a formula for calculating this which I believe was mentioned in a earlier Q of the day post about bolts. Otherwise I have always done a sheer strength of a #6 drywall screw at 40# and a sheer strength of a 5/16" lag bolt at 200#. Don’t remember where I have heard either of these figures from however. SWL, Dispersement, and number used of course modifying this figure.

    416) Zinc plating don’t rust? In general it is correct but it does rust.
    426) Incorrect or correct. Remember that this gear is new in statement - not damaged. Might look into I believe it was why repelling shives are made the way they are, otherwise it was an article about something similar in repelling uses of metallurgy such as on a carabineer. On the other hand, the question was not very specific sufficiently I see now. A forged shackle might be more strong than a ... on the other hand on a pulley...
    473) What size nut driver do you use?
    475) Let’s say nylock nuts. Otherwise under types of nut, - that premiss of used nylock nuts, what about a normal nut would have the same stresses involved in wearing out in shock and live loading?
    488) Used to be 20' but came longer. Now you pay for the extra foot. What’s the standard length of a 2" Aluminum 1/8" wall pipe while checking the industrial supplier catalogs?
    489) You is good..., on the other hand, we should both research this one further or be challenged on that by others. This given the “teaser” is able to come all the way to the deck in being lowered to also mask the stage. This by way of various means of either straight lowering or French tab like draping styles. What otherwise would be the “teaser” in front of a main drape called as an additional question for those theaters that don’t really have a grand drape?
    490) Bettter answer than I remember for the questionable term.
    500) Stop it? We are talking about “Bouncing the main” for say a second or third applause are we not? I’m thinking body weight here.
     
  19. jwl868

    jwl868 Active Member

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    Location:
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    The one question I thought I could answer…

    410) Which pipe is not measured the same as the rest of the pipe: Schedule 40 black pipe, PVC, Pneumatic, EMT, RMT, Aluminum, Galvanized, or Schedule 80?

    I was on another tack with this question, thinking that the answer was EMT since it is electrical conduit and therefore not pressure-rated. (But I still don't know what RMT is.)

    But, ship's answer applies to aluminum structural tubing, which is measured as you describe, that is a fixed outside diameter and several different wall sizes.

    Aluminum pipe is manufactured using the same dimension schedule as steel and PVC, although the full range of schedules (compared to steel) are not available (Schedule 5, 10, 40, and 80 are typical, and 160 is available for some diameters.)

    The pipe schedule is a fixed inside diameter and fixed outside diameter for a given nominal diameter. (I don't know what organization established the schedule, perhaps ASTM, or perhaps the steel industry.) This dimension schedule can be applied to any material of construction, commonly PVC, steel, or aluminum. [I think copper and brass have their own system. Iron pipe has its own system.] [More importantly, nothing binds a given pipe material to the diameters/wall thicknesses to any system; some PVC piping uses a completely different system, called SDR (standard dimension ratio).]

    I believe (though my experience is limited) that with "tubing", the size means the outside diameter, and then the wall thickness is specified. "Pipe", on the other hand, appears to be specified with a nominal diameter, and then an inside diameter and outside diameter according to an established schedule or other convention.

    [I don't know if there are any other conventions for distinguishing "tubing" from "pipe". The differences may be within a given material. For example, plastic tubing tends to be flexible and plastic pipe is rigid. On the other hand, all aluminum products are rigid, but tubing is distinguished from pipe.]

    [All of the above applies to English units (inches). I know there are metric conventions.]

    [As an aside, "Pneumatic" and "galvanized" seem to general. Just about any steel pipe can be galvanized, although it is typically just used in plumbing and usually threaded. Many metals and some plastics can be used in pneumatic applications. For example, steel pipe can carry compressed air throughout a shop, then tools at the work station are connected to the steel pipe with polymer hoses.]

    The moral is: when ordering/specifying/buying any pipe or tubing, make sure you know the dimensions of what you are ordering.


    (But I still don't know what RMT is...)

    Joe
     
  20. ricc0luke

    ricc0luke Active Member

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    500) Stop it? We are talking about “Bouncing the main” for say a second or third applause are we not? I’m thinking body weight here.

    When you say that I realized my mistake... I was talking aboyt something else entirely...

    Bouncing the main is when the house curtain comes down and immediatly goes back up for curtain call, or just after curtain call for an encore.

    jwl868- Great info on pipe verses tube

    for #475 ship... is it something along the line of that on a normal nut you can't easily examine the theads to see what condition they are in?

    and the size nut on a 1/8" crosby... Ooo it's somthing like 3/8" or 1/2"? I don't remember this... Nico press is a beautiful thing... and I always just find the one that fits... I guess I'm not quite as sofistacated.
     

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