Design and Construction of the frame
Draft and/or draw out your frame, and check dimensions twice using math, your brain and tape measure before you start cutting and installing such things.
As stated, this is a 12' tall by 6' wide soft
flat as per normal construction of such a thing - even if larger in width than normal, but it also has a window inside of it. For easy transport, a carefully designed hinged wall which has two flats hinged together but has a single piece of fabric covering the
face of the two will
enable the
flat to be folded for transport but no visible seam much easier. Another possibility is a loose pin hinged and Dutchmen-covered seams and hinges that might be easier to construct. Given one can deal with extra seams - one each above and below the window at each corner, four flats can be made to encase the wall if the window is large enough to merit it. This would do away with a large
flat housing a window all together. There are other options as necessary.
The window dimension desired is unknown at the moment and thus any inner support locations are subject to change as needed once that window design, and it’s specific requirements are decided upon. This would need to be known before any lumber is cut. A center mounted 48" wide by 72" tall double-hung window that has an actor climbing
thru is going to require a slightly different framing than that of a window that’s an arrow slit in a castle wall which measures say 4" wide by 24" tall, and nobody is going to be climbing their way
thru it. Another question is the position of the window in being at what height, and what position it has in relation to the center of the
flat. There are lots of other factors such as rough opening requirements’ verses reveals (normally lumber attached to the window to make the
flat look thicker and wall like as an opening), and other
stock flat questions such as the normal height of toggles that will demand design of this wall as it would require of any component of the
stage.
Be the design on a napkin or autoCAD, such things as a
flat need to be prefigured and not winged and hacked out. Say that window has a chubby Falstaff climbing
thru the window (as a not too accurate but figurative example). Even given the window will have extra supporting members for the window, in it’s construction and
reveal, the
flat will require some extra work to ensure if nothing else that the fabric below the window does not wrinkle as the frame deflects due to the weight. Instead of using a light weight 1x3 for a
toggle, perhaps a 1x6 might be the best option given the stiles are beefy enough to transfer the weight. Instead of not supporting that window opening other than with larger toggles, perhaps given a fat Falstaff climbing
thru a wide window, that
flat needs a set of really supporting members going from the
toggle under the frame of the window to the bottom
rail. Than of course, the design could be a window screen-covered picture window such as in Hedda Gabbler’s parlor, than it does not carry any real weight beyond the weight of the window. What structure to supplement the toggles is necessary need to be pre engineered into the design. You do not have to be in accuracy down to the true length of that diagonal sway brace in cutting it to a 45° angle, but should be able to note the general and working heights required for toggles and size plus general length of the main framing members which can be later cut to fit.
If this wall is part of many and to be flown, you need to consider things like hinges and
hanging irons with the general structure in addition to whalers,
stiffener battens and other horizontal supports. Another question is if it is to be vertically supported by the floor such as by
stage jack tip jack or
stage brace, much less if the wall needs to be moved with or without its supports. If the walls need to be moved hardware for doing this must be preplanned into its construction. Hardware such as loose pin hinges and lash
line cleats, much less if it needs to be hinged from the front with hinges countersunk into the frame. If this window is part of a flown
flat wall, how it’s constructed could be an all together different story as to your need for weight savings verses’ structural strength and where supports are placed. Perhaps if a permanent show and one that are flown, a more
mortise and
tenon style would be better along with better grades of lumber. If the set is to be transported or live an expected life of a hundred years, a similar style of frame but in real 1" or thicker thick fir lumber that’s both
keystone and corner blocks, and mortis and
tenon would be more useful. It’s all in the design and production needs.
Where a
toggle goes could and should be very much be dependant upon chair rails, picture rails and other things designed into the set or other
stock flats that this
flat matches up to and needs to become similar to. Hang a window
flat and it still needs to mount similar
molding to that of other flats. You need to have similar braces and toggles to it. Building scenery is not just hacking together boards. It needs to fit a
pattern and design standard. Time spent in its construction designs will ensure you are not wasting time and materials at it.
As a designer of this
flat, it is necessary for you to also determine what style of fabric covering it will be used because they all have different shrink ratios and in general techniques for how it is applied or cut. See Below.
In the case of this soft
flat, its overall dimension is 6'x12' and the fabric for it will be cut flush to the front and back set by 1/4". How the fabric is installed is important to be known during the initial design
phase. If the fabric is only on the
face of the
flat, than your
flat can and should be full size. If the fabric wraps around the sides and/or back of the
flat, the fabric will account for a slightly wider overall dimension to the
flat due to the folds in it’s corners and fabric
thickness. This might not be a large amount of extra space the
flat will require but across a 30'
stage, those extra thicknesses might add up where accuracy is needed. Deducting 1/8" from its components for overall height and width will also have the added bonus of allowing it’s members to be cut from a single board and not end up with one shorter due to the cut on a board that is already the length desired, such as a pair of top and bottom rails can be made out of the same board when a deduction is made due to the saw blade’s
kerf/
thickness. You now would be able to cut the 6' wide toggles 5'-11.7/8" and deducted 1/8" off the rest of the components. It is preferable to have your flats slightly smaller in width than larger when exact dimensions matter and this might be a good solution to the problem.
Was this
flat to have fabric wrapping the
edge, Top and bottom rails would now measure 1x4x5'-11.7/8". Stiles will have a 3.1/2" deduction off each end for the rails, and a 1/8" deduction for the fabric. They would measure 1x4x11'-4.7/8". The toggles can be 1x3 if not supporting the window, or 1x4 lumber as a
stock size. Their length would be 5'-4.7/8". The overall length of a 3' diagonal brace would be 1x2x4'-3" as a starting maximum length than need to be cut to fit the exact space dependant upon
toggle placement. This 1/8" deduction idea is not a normal or standard
stock scenery practice but might be worth looking into. If this is done, permission should be sought by those in charge of the theater to alter from the norm.
The more normal dimensions used in the example below and to be used with a normal soft
flat would be the rails at the width of the lumber, in this case 6', the stiles at the height of the lumber, minus the width of the rails, so in this case they would measure 11'-5" given 1x4 lumber making up the
flat. In this way, toggles would measure 5'-5" wide. With careful cutting, 12' long lumber can still be used, have its factor length
edge taken back some to give a fresh and straight
edge to them, and all toggles and rails can be made out of the same boards. In this case, you can cut a
toggle and
rail out of one board. If 1x3 lumber is to be used, be careful to pre measure it’s width before figuring out what dimensions to cut the lumber at because widths on 1x3 lumber can vary anywhere from 2.3/8" to 2.3/4".
Cutting and measuring of similar pieces of lumber should be done at the same time if stop blocks on a saw are not used. Measure the first board, in this instance a
stile by deducting the width of the rails, or better yet
lay down the two rails on one end place the
stile perpendicular to them. Take a tape measurement from the side of
rail to the
point on the
stile which is 12'. This will ensure that any discrepancies in width on a
stile will not affect the true length of the
flat. It might be easier to use scraps from the rails to do this. Such scraps can also be placed before a stop
block preset for 12' to ensure the proper length is cut. The same technique can be used for the toggles in using scraps from the
stile for the
toggle’s length. Another option given lumber that is the same width, and a goal without stop blocks, but to ensure lumber is cut to the same length, is to place both similar boards into the saw, verify that the edges that are not to be cut are lined up with a speed square and cut both at once to ensure they are the exact same length. Always use the same tape measure for the same components of a
flat. Tape measures are individual in how much any one of them will be off, how much
play will be in the hook or how much out of square/true it is. One tape measure to another will usually not achieve the exact same dimensions especially with cloth tapes.
Layout and Construction:
Construction of this
flat requires a smooth
flat surface without any seams or other obstructions across it. The floor if
flat makes an optimum surface especially for a
flat this wide. However there is a good chance that it will become damaged so construction of the
flat on a good floor would be unwise without some plywood and perhaps plastic laid out over it for protection and leveling.
Mark the location of the toggles on the stiles, and
lay out the pieces into their general locations. Look at cut lengths and joints between the boards and replace anything necessary which does not have a good and flush corner, or sits at a different
thickness to a member it will be attached to. If possible, you should pay special attention to and check the board’s ends provided by the saw mill. Do not trust them to be square, they have been known to be off. Where necessary, cut your own ends which will expose fresh grain that is free of splits or in being overly dry for gluing. Verify that your saw is also giving a true 90° angle by way of accurate square or an end for end test on a piece of plywood. Cut the plywood, draw a
line following that cut, than flip the board over and see how close to the
line it is. Most saws will allow for micro adjustments to its settings to compensate for this.
In cutting the blocks on the table saw, a panel cutting
jig for it would be the best way of cutting the keystones and corner blocks. Read a table saw or woodworking
book on making such jigs, than once it is set up, such a
jig can be saved for future work. If there is not time or ability to make a table saw
jig for the splints, use of and extending for support, the saw’s bevel
gauge will be necessary to cut the angles safely. Remember in this instance to adjust the rip fence on the saw so that it does not extend past the mid
point of the saw blade. Otherwise when pushing with the bevel
gauge or stick - depending upon which side the bevel
gauge is on, and having the plywood ride the
rail, it is very likely that once the plywood reaches the mid section of the saw, it will bind and even shoot or kick back the splint back at the user. Notes on cutting the lumber, if you set up a proper saw table, be it a radio arm saw, a miter box, or other, it should have a long side table and fence to ensure such lumber is well supported and kept perpendicular to the blade, such a table can also have stops mounted on it to ensure that the lumber will be all the same length no matter how many pieces are cut.
As for saw blades to do all of this with, use a other than construction grade cross cut 42 tooth cross cut saw blade on the 1x lumber if you want a clean cut. Due to its
thickness, it should not be necessary to have fewer amounts of teeth on a saw blade for a quick and clean cut, that few teeth will instead rip up your lumber as it cuts it. The more teeth, the smoother the cut, but the more chance it will burn as it cuts because it takes longer to cut. A good balance such as a 60-tooth 10" chop saw blade would be fine for this
thickness. You also get what you pay for on saw blades in general. Those blades up in the $60.00 starting range will last much longer, stay sharper, and have fewer problems with buildups on the blade causing it to dull, and in general give a better cut. For the table saw blade on ripping lumber, it should be a good carbide rip blade due to the amount of time it will spend inside the board and operating temperature it’s working at. For thin plywood, any blade from a
veneer cutting saw blade to a finish cross cut blade would give a much cleaner cut than that of a normal crosscut blade as long as you
send the material
thru at the proper and slightly slower speed. Saw materials with good sides down amongst many other tips that require training for.
With the boards in their rough but unfastened locations, check the
thickness of the boards as they meet up with each other, and for warps, twists and other problems. An idea might be to fasten the boards making up the
flat once the
butt joints are glued temporarily to a work table or the floor with drywall screws, finish nails with slightly exposed heads for pulling them later, or 6d or under sized double head nails from the mid - non blocked sections of the
flat so that they stay in place, square and with joints tight to each other while working on the support blocks. (Stagecraft handbook c1995) Use of a 24" framing square can help in this assembly. Replace warped or twisted lumber. If the
thickness of components is 1/16"
thickness in difference or more, they should also be replaced or at least reversed and looked at for possible use on the other side of the
flat. Place the lumber with it’s best and most smooth side down so that fabric installed on it will not show any problems
thru the fabric. If difference in lumber
thickness is not much, the joint can be sanded flush on the rear of the
flat, each board to each other with a belt sander as long as it will allow the
face of the
flat to be
flat and splints placed over the rear of the
flat to lie flush. Otherwise if the lumber is not of uniform
thickness, once the splints are on, any discrepancies in the
thickness will show up on the front finished side of the
flat and be very hard to remove. Other sanders such as a rotary or random orbit sander, much less a
power planer can be used as necessary, but only with more effort as this is not their primary function for this application and they can dig into the wood or cause it to become off. Also make sure that the
rail does not exceed the
stile in length by more than 3/64" or the sides of the
flat will be bowing inward and the
flat will be difficult to make perpendicular later. Some sanding of the end grain of a
rail might be required and necessary for neatness, but too much sanding can
throw it off.
When using a belt sander, keep it moving, do not allow it to sit
in one place and dig in. Also, let the sander’s weight do the sanding. With a lot of pressure on the belt sander, it is far too easy to damage the motor, or make what you are sanding become un
level by just a little more pressure on one
hand than another. The hands support the sander and provide a
bit of weight to it, not much more. Keep the platen - that
flat plate on the surface of the material to be sanded. Do not try to sand with the tension wheels or space between them and the platen. Keep the belt moving across the surface linearly to it as well as with its length, and for normal purposes you want to sand at a 45° angle to the grain. Sanding perpendicular to the grain will cause the sand paper to dig into the wood faster, and probably too fast. Sanding parallel to the grain will not sand as fast and if not kept at a low speed, might burn the wood. For the application of sanding a little off the one board when making it into a
butt joint, 60grit sand paper will probably be the right grit to use. You can use 50grit, 36grit, even 24grit, but would need to be really careful or the tool could dig into the surface too fast for you to control it. Sand the joint with slightly differing thicknesses by orbiting around the area and feathering out the depth that you cut into the thicker board so there is not a recess where you sand. Watch the
pattern of scratches the sand paper is leaving in the lumber. When the scratches at the joint match up and there is no gap between them, it’s a flush joint. Watch also at the joint for those scratches to ensure that one side of the joint is going flush and thus deeper in cutting than the other part of it.
After the joints are flush and the same
thickness, glue the
butt joint surfaces together. This is not the most strong of joints, but the glue will help hold the
flat together and tight to the extent such a joint will allow in being supplemented by the plywood splint afterwards. Gluing the
butt joint while not specified in most texts will help to some extent, enough if properly applied, and not too thick, to keep the frame rigid, at least a little more than just with a splint/
corner block. See biscuits above for a second technique worth looking at to help in keeping the frame extra rigid and long lasting. Do not use white glue for holding lumber to lumber. It has a thinner holding strength, moisture resistance to break down, and absorption rate into the lumber’s grain or poors. Never just put a bead of glue onto a surface because it will not distribute itself evenly across the surface of the joint causing the surface area to have less of it bonding together, and will be too thick. Spread the glue evenly across the surface to be attached with a paint brush or other tool such as a
putty knife or
shim. Glue is best when it coats the surface with a 1/32"
thickness or slightly less. More than that and there is too much glue as with just putting a bead of it down above, that glue in the joint will not properly bond the materials together. It is permissible to slightly water down the wood glue to help it spread better, but watering it down by 1/4 or more will make it too thin and not bond correctly. 1/10th thinning would be preferable as an amount. Always blow off and/or brush off the surface of the lumber and plywood after cutting it, especially before gluing it or it will have trash in the way of getting a proper bond. For things such as corner blocks, it might be easier to
trace the shape of the splint on the frame and spread the glue on the frame rather than attempting to get it just right on the back of the plywood.
If making more than one
flat to the same size or similar sizes, once the first
flat is built, before the first one is moved, screw some
blocking to the corners so the next
flat can be placed in the same locations without necessitating as close attention to keeping subsequent frames square. Verifying every other or every third frame is still square should be all that is required especially if all lumber were cut at the same time and stop blocks were used for the saw table to ensure all lumber is the same length. Such a table set aside for only making flats, with pre made or easily set up corner stops and even
cinch plate, and when not otherwise abused, is very useful for quickly making easy and accurate flats if a scene shop has room for it. Otherwise a few horses with plywood splinted together to be just larger than the
flat, or a few shop tables clamped together should suffice especially if they are slightly larger in size than the
flat you are making.
Once all joints
line up and are flush and the same
thickness at both the top and bottom of the
flat and glued, use a tape measure to measure the cross dimensions on the corners of the
flat. Cross corner measuring is necessary to ensure that the frame is square. For this length of
flat especially, if not all flats under construction, cross corner measuring will prove much more accurate. Other methods like a carpenter’s square or the ‘3,4,5' method will not be as accurate but can be used for mounting internal framing members. Remember to use the same tape measure and not two for checking if square unless it can be verified that both tape measures are giving the exact same dimensions. Also be sure to verify that the cross measurement is aligned and read from the same side of a tape measure or it can be off by up to 1/8". Accuracy needs to be to about the 1/32" in accuracy especially on long flats or it could mean a
flat that is up to 1/4" out of square given the length.
Once square, check again the joints for how square and tight they are. If reasonably tight, glue the corner blocks using the same technique for spreading glue onto the corner blocks as with the lumber on its
butt joints. Work quickly because the thin layer of glue will dry far too fast to pre glue what is not ready to be fastened yet. Remember that the grain of the
corner block needs to be at least perpendicular to the joint, if not with its grain running diagonally to it. The
corner block will also need to be back set from the outside
edge by 3/4" to 7/8" in allowing for the fabric to be installed and stapled without necessitating it’s wrapping over the top of the
block which can cause wrinkles, or in leaving space for hinges and other hardware to be at the corner of the
flat. Such offset from the
edge dimensions can be easily transferred to the material with a combination square,
compass or
mortise gauge or
line marked on the lumber by scrap board placed on
edge and flush to
edge of the
stile. Installation of the
corner block should go on the opposite side of the
line with the
line showing to allow a
bit of extra clearance for flats. The most important reason for the back set blocks is for attachment of other flats perpendicular to and attached at the rear of this one. If you have blocks in the way of another
flat butting up to its rear, you will have a 1/4" gap between flats that can be seen from the front. Some older texts and methods will note the corner blocks should be spaced only 1/4" from the top since with full length 14' to 16'
foot flats there is no need to stack other flats onto the tops of flats, much less install sections perpendicular to it. Doing this it will add extra support, but this will also prevent the
flat from being used in any direction such as horizontally in its future. (However, even there it is better to set them back by about a quarter of an inch, to prevent the plywood from catching on irregularities in the
stage floor and splintering when the
flat is slid along. - Theatrical Set Design c1969)
Use a #6 size counter sink drill
bit to pre drill 11 holes into the plywood
corner block as they appear in the Backstage Handbook
page 278, or other guides on the subject. This will provide the proper amount of holding
power of a
corner block to the lumber below it and help to ensure that nothing becomes loose or splits later because of too many fasteners or not enough of them to hold the plate on enough. As a general rule, all screws attached to lumber should be spaced back from the end of a board by one inch, and all screws attached close to the side of a board needs to be away from it by 3/8" or there will not be enough strength in the board to prevent it from splitting. Groups of three fasteners will hold the joint tight both vertically and horizontally as opposed to only holding it in a
line as if a hinge with two screws.
Be observant of where subsequent screws are in relation to other ones as they screw into the lines made by the grain of the lumber and plywood. In general, a screw or other fastener acts as a
wedge in going into the wood. Attach a second screw into the same
line of grain already weakened by one
wedge and it doubles the chances of splitting the lumber - especially if dry. In lumber do not attach two screws in that grain closer in proximity than two inches to each other. In plywood, it should not be closer than an inch. Screws should be no closer in hitting parallel grains than ½" in cross grain proximity to others, or it could also weaken the board. These are all notes for what is called staggering the screws or nails.
Ensure that the drill
bit part of the
countersink is adjusted for no deeper penetration into the
flat than 11/16". It is said that 80% of a screw’s holding
power is in the tip of the screw, I don’t know how much faith I would put into this but it’s best to have as much gripping
power on the screw as possible. Countersinking and pre drilling helps to ensure a screw will not split the wood, and ensure it will go in all the way, but that pre drilled hole should not extend past the tip of the screw, nor should it drill all the way
thru the lumber. The depth of the counter sink part of the
bit needs to be just short of the head’s diameter of the screw. Otherwise it will allow the screw to sink too far into the lumber if too deep, or not far enough if not countersunk enough. Be very careful to get the depth right with a
countersink bit, and occasionally clean out the pulp and saw dust that will otherwise fill up the grooves and slots on a
bit, before such blockages make it harder to drill.
The best screws for this application would be #6x3/4" zinc plated
flat head, normal or narrow
profile, #2
phillips head, wood screws. A normal
flat head top will require the
countersink, the narrow
profile while it will not provide the holding
power should only require pre drilling and not countersinking the hole to get the screw to go in flush. Screws should go into the lumber with a 1/32" recess below the surface of the plywood. No more and no less. If more, the screw will not hold the plywood in place as well and the tip of the screw will possibly pop out the front of the
flat and if other than a concrete floor, attach the
flat to the surface below it. If the screw is not slightly recessed into the hole, during normal use when the
flat is placed
face up on
stage and slid, the screw will dig its way into the floor and scratch it. The proportion and type of threading on this specific type of screw for its length, will provide the best holding
power above any others for this application. Since there is a
pilot hole used in this application, blunt tip verses pointed, even sheet metal screws if similar should work.
A 3/4" drywall screw, even if corse threaded will not provide sufficient holding
power or prevent the screw from stripping instead of digging into the lumber. Such screws might be fine for holding cardboard to lumber, but not much use for anything else.
In the past, all soft flats will have had their keystones and corner blocks attached to the frame with clout nails which were specifically designed for theatrical applications. Such nails are cut instead of
wire shank, has a chisel shaped instead of a pointy tip and is low in carbon content. The nails otherwise would be similar in appearance to a carpet tack except that the tip of the
nail is meant to be driven into and
thru the lumber, it than hits a steel plate called a
cinch plate which is placed on the other side of the
flat, than bends or even reverse direction like a hook back up into the lumber it was driven into. In other words, this
nail, once driven into that steel plate called a
cinch plate, will lock the
nail and thus splint permanently into the lumber. It is very important to drive the chisel tip of the
nail perpendicular to the grain of the 1x lumber it is to be driven into or the lumber very likely will split instead of be cut
thru by this type of
nail. Driving the clout nails into anything other than an at least 3/16" thick steel
cinch plate, such as a concrete floor will normally not be effective in making the nails become flush to the
face of the
flat should the nails chip the concrete and not rebound and be flush because of it.
Cinch plates are very necessary but should not be too thick or the lumber will be harder to keep square atop it. With such nails, the joint might loosen some with time of the lumber around it deteriorates but the nails will never come loose unless their tips are forced to straighten out. The blocks they fasten will never come off even if the glue completely fails and clout nails can often be re hammered tighter should the lumber shrink or be damaged. 1.1/4" Clout nails while difficult to get are still available. You must re square the frame between the first and second nails on one board, and the first and second nails on the board the
corner block is attached to, on each corner to verify the
flat is still square. If not due to the hammering, the
flat could be shifted and knocked out of square or the joint having been moved. After the
corner block has at least 4 nails in it, it should remain square for subsequent nails. If clout nails are not flush to the
face, after the frame is constructed, the
cinch plate can be put under the
keystone or
corner block with the
flat face up, and the tip of the
nail can be hammered deeper into the lumber. Be careful to not overly hammer the lumber or it could leave a viable
mark on the finish surface. Waffle head hammers also should not be used on the tip because they might damage the
nail, but can be very useful to drive them into the
keystone. For preventing this, clout nails as per Stagecraft c.1978 p123 are recommended to be driven into the plywood one or two blow past what seems far enough. This will ensure that they are fully cinched and probably also counter sink the head so it cannot scratch floors when laid
face up.
Essential of
Stage Scenery c1972 mentions another way Scenery Nails of mounting/nailing keystones and corner blocks to the
flat. It would not provide as strong a joint, but they were easier to remove and did not require a
clinch plate. Such nails could be used for temporally installing a
toggle on a
flat, or other temporary braces that were meant to be removed - remember drywall screws were not on the market yet - much less much in the way of
Phillips head screws of any type at this
point, the most automatic screw
driver that was available for slotted screws and square head
lag bolts was a
Yankee Screw
driver that took some work and training to use. Given this, nails would probably be faster and easier to use. Also mentioned for use of old style screws for joining the scenery are both a
pilot hole and use of small finish nails or
wire brads to keep the
block in place while turning the screw. This should not be necessary with the more parallel shank to modern wood screws. Such nails were described as “3/4 inch long coated head nails” (Essentials p111). These nails are slightly under described it would seem and I have never seen a product currently on the market under that description. Possibly some sort of joist hanger
nail, or short length of a ring shank drywall screw
nail would work for this purpose, roofing nails while short will have very thick shanks and very hard to
countersink heads.
Do not use any other type of
nail for soft
flat splint blocks. They will not have the holding
power in this
thickness of lumber, probably split it, and wiggle loose with time.
The more modern, quick and easy method currently most used to fasten a
keystone and
corner block to a soft
flat is with a pneumatic “M” sized gun using the proper air pressure and 18ga. 3/4" long x7/16" web staples. Other types of pneumatic staples such as the 1/8" web narrow
crown type will not hold the
block sufficiently and be of too small a
wire size in preventing the splint from failing. Other pneumatic fasteners will have similar problems with either going in flush, or properly bonding the splint to board. When using an “M” gun, you want to ensure that the web of the staple, or the bridge between its legs is installed in a direction other than parallel to the grain or it will not hold properly.
An alternative method for fastening the blocks to the lumber would be to use #6x1" black oxide coated, bugle head, coarse thread, drywall screws and cut off the tips so that they don’t poke
thru the front of the lumber. #6
Wire size of screw shank because the larger #8 thick screw might split the lumber in being too wide for the
thickness of the lumber and proximity to the
edge of it. Also, the extra sheer strength of the #8 screw is not necessary for this application. Black oxide coating because it allows paint to stick to it more readily and such a coating adds an extra surface hardness for strength to the screw, over screws with zinc or a galvanized coating to them normal for an exterior grade screws. Coarse threaded screws are necessary for this short length of screw because a fine thread will very likely strip with a
power tool driving it in. The depth of
pitch on the screws is going to increase the
grip thus holding strength of the screw into the lumber in compensating for its shorter length. If installing by
hand, a fine thread should suffice, but otherwise they tend to strip in lengths under 1.1/4" too easily. Bugle headed screws are a type of
flat head with a more gentle slope to the head which adds to the holding
power on the surface of what is being attached over that of the holding
power of a normal
flat head screw. This bugle head however more requires the
countersink because of its slope than a normal
flat head, in this short of a screw not having as many threads into depth to pull it into the lumber. Finally, on a drywall screw, what type of
driver head it uses, Phillips, square drive, Robertson
etc. is not very important because the screw once installed will not be required to be removed.
The reason you need to cut the tip off a drywall screw is that the actual
thickness of the material you fasten is going to be 31/32" thick. Plywood is 1/32" thinner than its nominal dimension. By the time you recess the screw into the splint another 1/32" it’s going to be sticking out the front of the
flat by at least 1/16" or often 3/32". Good enough to cut you, fasten the
flat to the surface below it, and cause problems with laying fabric on the
flat’s
face. If you can find a 7/8" drywall screw, it might be optimum, otherwise cutting off 1/16" to 3/32" from the tip of a drywall screw should be sufficient to ensure it will not pop out the front of the
flat, but still have enough threads on it, unlike 3/4" screws, to properly fasten the
corner block to the boards below. Since you have a
pilot hole, and threads behind the cut tip to
ease in and
grip the lumber and thus force the blunt tip into the wood, there should not be a problem with the screw going into the lumber. In this case, the screw will act as per a blunted tip
nail in cutting it’s way into the lumber instead of splitting the lumber as it enters. In cutting into the lumber, the screw should
grip just as well in counteracting the 80% of the tip holding theory because those cut fibers will
wedge the screw into place and prevent its removal just as sufficiently. Sanding the surface of the
flat in getting rid of screw tips popping out can lead to marks that will show up on a faced
flat, and also the exposed metal of the screw might rust causing corrosion to the wood around it and potential rust marks to show
thru the fabric of the
flat. In addition to that, as the wood shrinks, those sanded flush screw heads could become raised again. Cut the screw tips once they pop out of the
flat, or before you insert them into the lumber with hardened steel dikes or carpenters pinches. A carpenter pinch is designed to cut the softer steel on a
nail, not that of black oxide coated drywall screws. In other words, normal tools used to cut them might develop dings on the blade surface. Precutting the tips on screws will if they pop out the front of the
flat ensure that the sharp tip will not rip up the sand paper used to flatten them down. You might not be able to otherwise
grip the 1/16" tip of a screw sticking out of the lumber with the pinches.
If you are not concerned about rust, and are able to sand the
face of the lumber with say a 120grit belt sander paper, than an even better option might be to use #6x1.1/4" drywall screws of course or fine thread for attachment of the blocks. In this way there will be extra length extending past the surface of the lumber to grab with pliers, and fold to break them about flush to the surface, than sand them. This method will provide a screw with the maximum holding
power, but it is counteracted by the possible damage you can be doing to the lumber grain around the screw as you attempt to break the screw. It might be more wise to cut the screws than attempt to break them, especially near the edges where that abuse to them could cause the screw to split the lumber. In belt sanding screw tips, remember to watch the scratch marks of the sand paper on the wood to see when the screw tip is flush. Keep the sander at a 45° angle to the lumber for easiest observation of the scratches and to keep the sander moving linearly across the screw tip or the screw will cut up the sand paper by wearing it too much
in one area.
Cordless drills or cordless screw drivers are the best tools for installing screws into keystones and corner blocks. Corded drills do not have torque/clutch settings and are thus difficult to ensure the proper depth every time. If you do not have a cordless drill with clutch settings, drive the screw by
hand, with a ratcheting screw
driver, even a
Yankee screw
driver. Any such method will be otherwise preferable to a drill especially when used with a
countersink bit and
pilot hole which can be drilled out with a corded drill.
Set the clutch of the drill to about a #3 setting and do a test screw with a, for the most part fresh battery to check it’s depth. Adjust as necessary with other test screws until you have the bulk of your screws going in at the same and proper depth. The clutch setting should pop when the screw is in place and the right depth or tension, or as necessary, just before it. The screws should not go in too deep or you will have to sand them. As the drill’s battery is used, especially on old batteries or lesser quality ones, there will be a
drop off in
power which very likely will cause the clutch to go off sooner than it should. This is normal, do not adjust the clutch to allow for a deeper screw or your settings will quickly become off. You can finish driving the screw by
hand later or if the drill is variable speed, finish driving the screw at a low speed afterwards with a fresh battery. Do not use the drill in high gear. Low gear will give a more uniform speed and a charge that will last for a longer length of time. It will also ensure that the screws are not going in too deep before they activate the clutch when it is turning at 400 RPM rather than up to 1,750 RPMs. This all is especially important if your drill is 12v or less in
voltage. A higher
voltage drill might be able to drive a ton of screws in high gear without it wearing down the battery too much, but it is still going to be harder to ensure the proper depth or clutch activation given the speed.
Frequently when you install a fresh battery in the drill, it will make the clutch setting drive the screw a
bit deeper than it should due to the higher than normal
voltage coming off the battery. Be aware of this possibility in running the drill at a slower speed to watch the depth and manually stop it as necessary. You can also adjust the clutch setting down one notch to compensate for this because it will become readily apparent when the overcharge bleeds off. Another option for use here would be to use Phillips drywall screw shooter collar tips in the drill, which will by nature of their stop, prevent the screw from being driven in too far. Such bits are a little more difficult to see what you are doing, but can be of use when learning or having trouble ensuring the proper depth. Install the first screws when using a fresh battery along the sides and corners of the
flat so that it is easier to get at anything that pops
thru the front and needs to be sanded. Such places will also be more likely to be masked by
molding and
Dutchman seams.
Another cause of your drill at times stripping the screw or otherwise not driving it in far enough is improper orientation of the drill to the screw and holding the tool in the wrong way. From the tip of the drill to its rear, imagine a axis
line that the tip revolves around. That
line needs to be the same
center line as that of the screw or the tip will not have enough surface area in contact with the screw to drive it well once it gets to the end of the screw where more force is required. Have someone watch you drive screws to ensure that the
driver is perpendicular to the surface you are screwing because it is very hard otherwise to see when you are doing it wrong without a lot of practice in doing it right. Extend that
center line from the screw
thru tip, and all the way out to your shoulder. Driving screws short of lots of experience requires your shoulder to be in
line with the axis of the drill. Otherwise keeping your shoulder behind and in the direction of force will keep the screw going in straight and help give the proper amount of force to the screw to drive it. Depending upon what type
T-Handle or Pistol
Grip drill you have, it will also require different ways to hold the drill in the
hand or with the second
hand to help. Get instruction on the proper way to hold a drill.
What is called an Anti-Cam Out, type screw
driver bit will also help the
driver grip the screws in driving them in. 2" Anti-Cam Out
Power Bits that have a recess for gripping into a
bit holder, when coupled with a
power bit type counter sink
bit will
ease and speed the entire operation. Otherwise, if you use hardened tips, they will last longer. Once a Phillips
bit seems to be rounding off and gets shiny, it is going to become more difficult to get the screw in all the way without stripping them. You get what you pay for, with cheaper bits, you need to change them sooner.
If any screws break, remove the broken off head of the screw or it will fall off later and probably stop a scenery
wagon from moving, and leave the rest of the screw in place. It will not be sufficient holding
power to attach the splint, you need to replace it with another screw, but otherwise the threads of the broken screw will not cause any problems unless it forced the splint to raise above the lumber. This could be and should be corrected by a hammer because the splint needs to be
flat to the lumber.
Next attach the keystones to the toggles in the same glueing, screwing and back setting from the
edge way similar to the method used for corner blocks. It might be necessary to remove any nails or screws temporally holding the opposing stiles in place and to use a bar clamp to push or pull the frame a
bit to make the
toggle fit if the lumber is warped some. If the lumber is warped or bowed outward, the tendency of the lumber will be to force the joint apart. This should only be done after the corner blocks are in place. Attach any window support members necessary to support the window with their straps. Strap length might need to be longer if your window as above is going to weigh some and be operated or climbed
thru so that a window support brace kind of like a
leg can be installed directly under the window side brace to directly transfer the weight downwards and pull some weight off the
toggle attachment to the
stile that otherwise would be carrying all the weight. If the window does not weigh that much, it might only be necessary to install a support brace/
leg directly under its center to carry the weight. In which case strap length would be normal. In supporting the window, it might also be wise and necessary to install a brace atop the window between toggles to add some support above the window.
Actual dimensions for the lumber used would much depend upon the size of the window intended or installed in the opening. If fabric is to wrap the window opening, you must deduct at least 1/16" from the dimension given the inside corners of the material are cut away to prevent an otherwise necessary wrinkle or fold. In addition to the 1/16" for fabric, you should add at least 1/8" all around the window size so that the window
unit fits into the opening without a problem. Most
stage window units are much similar to the window units available pre made and
drop in that are offered at home centers that are shimmed into the rough opening and screwed into 1x4 or 2x4 blocks that are screwed onto the back of the toggles or braces for support and a wider attachment surface. Other types of windows require a
bit more external bracing to them for wider reveals and
face frames, and because of this will also require a larger rough opening and possibly supplemental support for the window in addition to that of the
flat’s frame.
A doorway will be much similar to that opening in a window except that the two legs of
flat to the sides of the door need more bracing to the above door section, and there is a reduction in overall height in the
flat for the saddle or
sill iron that acts sort of like a
threshold, but in this case keeps the doors legs spread as if a
toggle.
Finally, re square the frame with a tape measure and adjust as much as possible back to square, than measure for and cut the diagonal brace to fit. It’s easiest to be careful when installing the keystones and corner blocks so as not to move the frame, or at least if you think you bumped it out of square, to just stop and re square it. Attempt still, to verify the
flat is square and correct it as possible, this is your last chance. The diagonal brace is easiest to simply
lay over the top of the
flat’s
stile and rails, verify the angle with a speed square or tape measure to the corner - in being the same, allow room for the half straps not to hit keystones, and
mark where the brace needs to be cut. Cut it at a 45° angle on both sides, glue it into place and attach the half strap again in the same
pattern as laid out in the Backstage Handbook.
One note about using a 1x2 or 1x3 lumber for toggles or diagonal braces that will necessitate modification to the width of a
keystone or half strap is that with less width in the plywood, the joint is going to have less plywood crossing it. A 1.1/2" wide section of plywood crossing the seam for a 1x2 brace is not going to give much support to the seam. A 8"x2.1/2"x1.3/4"
keystone on a 1x3
toggle might be sufficient for a smaller
flat, but will not be for a 4' wide
flat. Instead of using the standard splint shapes, for smaller lumber braces you can use scaled down corner blocks to provide proper support to the seam. Normally and why braces are sized down slightly smaller than the outside dimensions of the lumber it holds together, you do not say, want anyone using the splint for a handle or tie off area because it could weaken the support. On a
corner block however, there should be enough lumber crossing the seam, and surface area attached to the lumber that this will not be much of a problem.
Other options for building the
flat which is not standard but can be done, are in reducing the 3/4"
thickness of the toggles and various other braces to say 11/16" when they are not required to have openings or structures attached to them such as for a window. This will reduce the weight some and reduce the surface area of lumber touching the fabric that if the fabric is not stretched properly around, could show
thru the surface of the fabric. Frequently as the
flat gets older the fabric between the supports will stretch slightly and show the supports that are still stretched and often supporting the fabric when paint seeps
thru it and bonds the fabric to frame. This especially will show diagonal braces that are otherwise hard to mask by
molding and
Dutchman. So reducing the
thickness of a diagonal brace, and not fastening it to the
muslin might be an option. On larger flats such as on anything 3' and wider, those unsupported lengths of fabric without direct attachment to toggles would be more prone to stretching and sag, not to mention it unsupported would be more likely to have problems with tearing and ripping. I do not advise reducing the
thickness of the toggles in this case, but it might be a good idea for the diagonal brace. One final problem with reducing the
thickness of toggles is that if you go to install anything from a
picture hanger to
molding across it, the fabric is going to show either a space behind it given fabric stretch, or you will need to
shim the brace back up to its needed
thickness so as not to have a bunch of warped
trim all over the set. This is all also more advanced technique in
flat building. When learning it’s too many details to attempt to do properly. Instead, it’s easier to keep to a all 1x4 framework or a 1x4 and 1x2 for the diagonal brace, in the frame.
In addition to this 6x12
flat being about the maximum size it can be in size which will also allow it to fit
thru a door way and maximum in size for the strength of the lumber used for it, something to consider about it is that the extra width will also necessitate a wider, more expensive run of
muslin than the normal 54" wide seamless
muslin that would be good for the normal width for a 48" wide
flat. Your fabric will need to be at least 76" (81") wide unless you plan on having seams that will be difficult to mask short of
molding covering it. This would be a good reason
stock flats are normally only 48" wide. The wider the
flat, the less seams it has, but the more it costs to
build, much less, harder it is to move the
flat around corners or transport in general. The weight of the
flat also can cause it to warp if not stored properly making it a waste of money. All that said, it’s still going to be a few less seams to mask, and much quicker to install them due to there being less of them in number.
Allow the
flat to dry once all its braces are on at least a few hours without moving it or working on it further. Than drive any screws not fully countersunk the rest of the way in, or sand them with that 120grit paper as needed to be flush.
Hand sand with 60 or 80 grit sandpaper all surfaces on the rear of the
flat, to prevent slivers and splitting. Once dry, and the back is done, flip the
flat over and look at the seams on the fabric to verify that they are flush and
flat. If joints at this
point are not absolutely flush, you should slightly sand them flush with a say 80 or 120 grit belt sanding paper. It shouldn’t require much work to the joints if care was taken on the rear of the
flat in making corners flush and built right. The more sanding and prep work to the
flat you do before the fabric is on, the better the end result. Keep in mind the angle of sanding. In this case it should follow the grain of the lumber with the sander moving laterally and all about the area of the seam, to ensure it does not sink in too deep for the little amount of adjustment that should be required. Don’t forget to blow off or at least brush off any dust across the entire surface of the lumber before you add fabric to it. Also, should any screws pop out of the
flat’s lumber, sand them flush as well and perhaps consider adding some primer or Killz to what you sand so it will not rust with subsequent layers of fabric and glue/paint that might keep the untreated metal wet long enough to rust. Probably not necessary, but if you have a lot of them to cut and sand, it might be worthwhile to paint and treat them. Remember in sanding, that the goal is for a smooth surface and it’s better to have a surface with a few discrepancies which are covered, than something with an over sanded or worked on area. Complete work to the front by lightly
hand sanding all surfaces so the
edge of the lumber cannot cut into the fabric over time or with stretching it over the surface. Daniel Ionazzi in Stagecraft Handbook p122 recommends routing the inside edges of a soft
flat to prevent the solute of the lumber framing behind the
muslin from showing
thru when scenery is brush painted onto the
flat. This routing should be done with no larger than a 1/4"
round over bit, and is an effective idea to prevent this and wear on the fabric.
Something that might be wise to do at this
point before the fabric goes on, would be to rig it for hanging, fastening or hinging as needed. This is absolutely required for hung flats, and in general a good idea for other hardware that needs to be permanently mounted to the
flat.
Thru bolted hardware is necessary for safe hanging, and hardware that would be unsafe should it rip out of the
flat. Each
hanging iron requires at least two out of four holes to be
thru bolted. Due to close proximity of holes in hardware,
thru bolting more than that can weaken the lumber it is attached to. Larger sized hardware can have up to three, but other holes in the hardware should be attached with wood screws. A #10-32 T-Nut with 10-32x3/4"
flat head screw would be the normal means of safely fastening hardware to the
flat. The T-nut must be properly countersunk into the lumber for it to disappear and use of thread locking compounds on the screws would prevent them from loosening. A 7/8" forstner
bit, if memory serves is the proper size and type of drill
bit to use for this application because it will not splinter lumber or over widen a hole as it goes in. Use this over that of a
paddle or other type of drill
bit, and counter sink the hole before attempting to
thru drill it. This
thru bolting method will provide a much safer mounting of materials than otherwise using
flat head machine screws on the
face of the lumber that will be drawn into the wood when put under tension and thus loosen up necessitating cutting the fabric on the
face of it to tighten the screw again. Also, there will not be any screw threads sticking out the rear of the
flat to snag other materials. Should the hardware need to be removed at any
point, the T-Nut should stay in place for the next use of it without popping out of the scenery or otherwise being noticed. Consult a scenery construction
book for more details such as where to install the hardware. If such hardware needs to be installed after the scenery is covered in
muslin, T-Nutting should still be done in the same way except the hole needs to be counter sunk slightly deeper so the hole can be covered with wood glue reinforced Water Putty or Bondo, than sanded flush. Such extra work can be done for T-nuts installed under
muslin, but should not be necessary given a properly countersunk hole.