I Need Help with our Meatracks!

[KingSky]

I know there is a thread about storing lights, but this is a little different.

Today i came into work and my Production Manager grabbed me and showed me that over the weekend a rental group had tried to move one of our massive meat racks, and in the process had accidentally caused the thing to collapse! It wasn't their fault, the welds that held the bases of the sched 40 frame had snapped while going over a door stop. Now we need to build new meatracks, as nobody has any confidence in the old design.

The old design consisted of a 1 1/4" steel box tube base with 6" castors, and schedule 40 steel pipe screwed into cast iron flange bases. The cross beams for hanging instruments were also sched 40 pipe, attached with Roto Locks.

In examining the old design, we realized that the reason it broke was because the cast iron didn't weld very well to the steel base, and the rotos allowed the entire frame to rotate and fall.

We think that if we could find steel flanges it might hold better, but i am hesitant to make a quick fix without examining other possiblities. I am looking into builiding the corner supports out of 1 3/4" and 1 1/4" steel box tube and having a larger area for the welds to hold, but am not sure about how well the sched 40 pipe will seat and hold with welds.

Oh, and the dimensions for the meat racks are: 3' wide, 6'8" tall, and 8' long. they currently have six rungs for instruments and can hold around 60 or 70 S4's, depending on how there loaded, but i think that they can be made to hold an extra two rungs for another 20 or so lights.

Basicallay i jut want to know what other people and places use for meat racks, and input on the Ideal meat rack. Thanks.

 

[derekleffew]

Moving this to Lighting forum, as I think you'll get better responses there.

... and the rotos allowed the entire frame to rotate and fall. ...

I don't understand; perhaps a picture of the failure is needed. If the pipe and Rota-Locks are forming a rectangular solid prism, how can anything rotate? I can see where the attachment of the cast-iron floor flange to the base is the weakest point, but could it be bolted rather than (or in addition to) being welded to the base of 1 1/4" steel square tube? Every meat rack I've ever seen has been made of square or rectangular tube, steel or aluminum, with only the fixture hanging bars made of round pipe or tube. The wiki entry meat rack has some pictures, perhaps others can share pictures and/or descriptions of their meat racks for comparison.

 

[Traitor800]

It is possible to weld cast iron to mild steel the best option to stick weld the two together. You should use a stainless electrode, I forget the number but any welding shop should be able to point you in the right direction. If you dont have the skill or capabilities to do it with stick then you can do it with Mig but you have to burn it real hot, and you should be able to tell when its done if the weld is solid or not.

 

[reggie98]

How about a picture of the failed section? The part(s) that you think is cast iron, maybe cast steel. Usually a very low grade of homogeneous steel similar to A36 and difficult to weld.

 

[kicknargel]

My steel supplier sells steel weld-on floor flanges for sch 40 pipe.

Other than that (and without seeing pictures) sounds like you need to make the frame more rigid--perhaps some diagonal corner braces so you don't just have a rectilinear prism with the ability to become a parallelogram.

 

[mjw56]

Sounds to me like you can skip the flanges all together.
Weld a square plate (or round if you feel like cutting out circles) 3/16" thick should be plenty, to completely cover the bottom of the pipe, leave a little extra to weld to. Weld all around the pipe(even though it's more weld strength then you really need), finally weld the newly covered pipe ends to the 1-1/4" tubes. since this removes the single piece of cast iron it should be significantly stronger than before. and less susceptible to brittle failure.

edit: attached the following
View attachment MEATRACKS.pdf
Note that this is not an engineered drawing and should be considered for conceptual use only, i assumed the pipe to be 2" sch 40 and based measurements from that assumption.

 

[DuckJordan]

Also unless it was done improperly (ex. welded area not cleaned before welding was done or even as simple as wrong amount of current going through the system If it was stick welded {personal fav for strength}) The weld should hold to at least 2k pounds of force the metal would fail before the weld did. My guess it was a failure of both design and of technique of weld. So a view i always take on things the more triangular you can get in your design the better (triangles are the strongest geometric shape).

 

[KingSky]

Update

Okay, so sorry i posted this and couldn't get back to reply. I didn't get any photos of the broken rack, but the design is the same on the remaining three, so i grabbed some pics of one of those. Sorry they're kinda blurry.

The base Flange:

The Side View:

The Corner Joints:

On the corner joints, what i figure happened was all the weight moving in one direction after the base had popped free, was too much for the roto bolts, and the way the short width bars are attached, they ended up being pivot points and the thing slide from rectangle as seen in the side view, to a trapezoid, propped up by a single wedged Source 4.

What we've come up with for a solution is to replace the vertical and short horizontal Schedule 40 pipes with 1 3/4" Box tube, using welds to attach the horizontals to the verticals.The verticals would be welded to the frame directly with triangle braces at the bottom on the outside for added support. The instrument pipes will then be bolted onto the short horizontals, and we are debating whether welds will be necessary. I also plan to add a fourth pipe on each row, if we decide it is structually sound enough for the added 320 lbs.

Waddya think?

And thanks so much for the quick and helpful feedback, you guys rock!

 

[ship]

Re: Update

scrap the idea of such things you use and start over. think C-Channel for bars / pipes of clamped fixtures installed and as welded as C-Channel pipe to a supported box frame of tubing. and as per cart on platform that survives transport.

Scrap it all and less or with what you would temporarlly rig for a grid, think what is a fixture supporting cart. Weld it or build it a per what it's used for not as what grid it might be used for.. The above welded hanging bar carts as with dual level road cases which house with flip up lower door to the under fixtures that are not hung but instead stored without pipe that's also a good idea.

If you gotta hang them, shouldn't the cart be made for that purpose and even different heights of what you hang in persay lamp bars full of what's hung of different heights thus as welded frame with different C-Channel places to hang them pipes that you hang from accessable? A rack full of pinspots vers S-4 PAR, verses any in varying size of Leko hanging from your meat rack seems really limited in other than adjusting the pipes for each class of fixture in use.

Why not have C-Channel slide into grooves and with pinned stops for them to hold them. This as C-Channel and welded to a box tubing frame - perhaps with storage atop in box for such stuff. Plumbing flanges etc.... come loose and not rated for such duty.

The other concept presented above, basically top heavy road box with two levels to it's storage but you don't need to hang each fixture from a pipe... just kind of put the fixture in the box and it's sized for X-amount of fixtures in the above and below section for it. Cool concept in saving time in having to hang each for transport.

Lots of other ideas out there, have not seen your's since I was in college I believe like 15 or 20 years ago. Pipe and flange type carts are not the best of options. Put on your thinking cap and design something better.

 

[KingSky]

What?

Im having trouble understanding what your saying, I think i would need a diagram, drafting, or picture to see what your getting at. Sorry, but your sentances just don't make a whole lot of sense.

Any type of road box is going to be far too heavy and too limited for the amount of instruments we need to store at any given time, and with the C-Channel, i don't really understand how the fixtures would attach. Are you saying that the instruments c-clamps would slide into the C-Channel? If so, what would hold them up, and even with some type of pin, i don't think they would be as secure as using there c-clamps as designed, and it sounds more complicated than it needs to be, having additional parts required for storage. I also don't think that track like that would be able to support the amount instruments.

But by all means, correct me, but a diagram or picture would be really helpful!

 

[kicknargel]

Re: What?

I think you could more or less keep these intact, with the addition of some biggish diagonal braces (2-3') welded/bolted/clamped across some of the corners, making sure to cover every possible direction. Right now you're relying on the roto-locks and flanges to stiffen the whole thing and they're not good at that. If you add diagonals (look at some scaffolding) the whole thing will be rigid and you're only using the floor flanges to handle the horizontal sheer force of pushing the cart. (That said, I still don't think I'd use that type of crumbly flange).

 

[bdkdesigns]

Re: What?

I don't think you want to add more pipes to those things, they already usually took at least two people to move them because they were so massive. I wanted to scrap them completely and rebuild something more along the lines of the Montana Rep touring racks. Those racks were just a pain in the butt, especially when they had to go out with a rental that left the building.

Oh, and I also uncovered some Rocky Horror Show slides while unpacking my things from the shop the other day......

 

[derekleffew]

Re: Fixture carts

Some (bad) pictures of carts.

 

[KingSky]

Re: What?

Well, we about finished the prototype rack today, just gotta add a couple more welds and paint it! The idea of bolting the pipes on was scratched in favor of welding them directly to the frame, so there is really no going back. However, i don't think they'll be much heavier, or really be able to hold more instruments after all. The thing with the old design is that instruments could be hung off the end of the cart, those pipes are now 3" box steel, so that's not gonna happen. I actually think that that is good thing though, because with the fourth pipe, i feel the instruments are a lot more secure than if they were hanging off the end. The box tube ended up being 1 1/2" for the verticals, and 3" x 1 1/2" rectangular box tube for the horizontal cross braces, and even though a little beefier, they feel a little lighter, and a lot more secure!

I don't think I've seen what the rep uses on tour, where do they store them, the fort?

The bosses are gonna have a look tomorrow when we finish and get it fully loaded, but i think we'll end up building another. Unless a better idea comes along.

I took these pics as we were finishing for the day, but i used my cell, sorry.
Corner Joint:

End Close up:

End Far:

Side:

 

[reggie98]

What is being said by others, is that since the hanging bars are fixed is position, the space is possibly being underutilized, depending on what is on the cart. One way to make the hanging bar adjustable without sacrificing rigidity is to employ a spring loaded shot pin to hold them in place vertically. This is common on adjustable height "plaster" type scaffolding, made by Baker, Perry and others. Similar to: Scaffold, Utility, Working H10 1/2Ft - Scaffolding - Ladders, Platforms and Scaffolding - Material Handling : Grainger Industrial Supply

 

[derekleffew]

KingSky , I like the new design, but now wonder if the casters might be a bit under-sized (hard to tell from the photos)? If the old cart stumbled over a threshold... After all, we're talking about ~1000 pounds of Lekos here.

What are you going to do with all the pipe and Rota-Locks you've freed up?

 

[shiben]

KingSky , I like the new design, but now wonder if the casters might be a bit under-sized (hard to tell from the photos)? If the old cart stumbled over a threshold... After all, we're talking about ~1000 pounds of Lekos here.

What are you going to do with all the pipe and Rota-Locks you've freed up?

I concur, the casters appear to be undersized. Ours are much larger, and we have no problems running over all sorts of things with a similar amount of lekos. Door thesholds, Audio cables, and freshmen being the major sources of inconvinience that need to be rolled over.

 

[KingSky]

Reggie,
I guess i don't understand why we would need the bars to be removable or adjustable?

Were just gonna keep the Rota's with our rigging stuff i guess, although we now have way too many, and that's just from one cart!

And yeah, The caster's really do need to be larger. We were so focused on the design and construction of the rack portion that we decided we would get back to the caster's later, even though it will be a little more difficult then.

We loaded it up, and it's a bit difficult to move alone, so i imagine we'll strip it down and fix them at the same time as we rebuild the others.

Thank you all for your input, it's been great, sorry that i didn't quite get or agree with some of the idea put out, but thanks anyways!

 

[ship]

Re: What?

Im having trouble understanding what your saying, I think i would need a diagram, drafting, or picture to see what your getting at. Sorry, but your sentances just don't make a whole lot of sense.

Any type of road box is going to be far too heavy and too limited for the amount of instruments we need to store at any given time, and with the C-Channel, i don't really understand how the fixtures would attach. Are you saying that the instruments c-clamps would slide into the C-Channel? If so, what would hold them up, and even with some type of pin, i don't think they would be as secure as using there c-clamps as designed, and it sounds more complicated than it needs to be, having additional parts required for storage. I also don't think that track like that would be able to support the amount instruments.

But by all means, correct me, but a diagram or picture would be really helpful!

Sorry,

Road box, basically a say ½" plywood framed steel box sufficient in height to have two levels of Lekos with a flip up shelf for two level storage. This box sufficient to store x amount of Lekos per level on the box. The box sides to the cart prevent the Lekos' from falling out of it but also no longer require the fixtures to be hung within the cart. Weight... not really much more as balanced by the pipes fixtures are hung buy in no longer being needed in.

For meat rack, instead of just putting fixtures in a box standing on their shutter mounts, hanging them 12-16" on center on say 5'-8" pipes - though not sure of the actual length or spacing. Three of these pipes per C-Channel. One pipe the end, one in the center and one on the other end with say six to eight fixtures per bar and three bars per row. Two to three rows of bars per meat rack dependant on fixture height and lots of the’s C-channels pre-mounted on the rack for choice of fixture. Such pipes mounted in the C-channel as retained in that mounting of the pipes by way of quick release pins or bolts.

I will look for some photos of the concept, sorry you didn’t understand what I provided so as to inspire in concept.

 

[reggie98]

Re: What?

Such pipes mounted in the C-channel as retained in that mounting of the pipes by way of quick release pins or bolts.

I will look for some photos of the concept, sorry you didn’t understand what I provided so as to inspire in concept.

That's what I was trying to show in my link to the scaffold with the adjustable height platform.