fitting together large rectangular frame from angle

OK, I have another one-guy-in-a-small-shop problem. I've made a bunch of
rectangular frames from angle iron, but this one is a little different. The legs
are much larger than my welding table. My welding table is about 4x5' and this
frame is about 6x9'. I do have some flat concrete floor space available but that
means no clamping to a table. This frame has to be square enough to drop over an
existing wooden truck flatbed.
Ideas?
Grant Erwin
Reply to
Grant Erwin
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you can make an exact copy of the perimeter of your flatbed with 2x4s (diagonally reinforced) and drop your frame over that copy. You need two 2x4x12's and 2x4x8's.
i
Reply to
Ignoramus10273
"Grant Erwin" wrote: (clip)This frame has to be square enough to drop over an existing wooden truck flatbed. ^^^^^^^^^^^^^^^^^ Forgive me if this is too obvious to even mention, but can you reach the truckbed with your welding cables? Then you can do the job "in situ." (Maybe use a pair of jumper cables as an extension?)
Reply to
Leo Lichtman
Welding on cars, is generally discouraged due to possible electronics damage... otherwise it would be cool...
i
Reply to
Ignoramus10273
No, the truck is two hours away from my house and across Puget Sound.
GWE
Reply to
Grant Erwin
Assuming you have some tolerances and aren't making this a "slip fit", tack it all together at the corners and then use a comealong to pull it along one diag axis to square. It helps if you can shim it so it is reasonably level(ie all elements are in the same plane).
Weld the two cabled corners.
Release the come along and check your square.
Repeat for the other corners.
I have done this for several dump box frames and it has always worked pretty well. Usually square within 1/2" measured diagonally on a 12-14' box. From the square I usually then have cross stringers, but it doesn't sound like you have this in mind?
Will you have any diagonal bracing over the top or anything? Dependinding on how you are doing this, it seems like you might have "opportunity" to rack the frame after it is built and placed on the flat bed.
JW
Reply to
cyberzl1
The client built a wood truck bed. 2x6s fore/aft sit on top of transverse 4x4s which sit on the frame. He wanted it low. The bed has cutouts for the wheels. After looking at it for awhile, he decided he wanted steel around the edges, with steps on the sides towards the front and a headache rack. And it has to drop over the bed. If it's a little out of square we can indeed probably tweak it with a comealong on the long diagonal.
GWE
Reply to
Grant Erwin
Telescoping tubing and make your own outriggers. Ive made a bunch of them for multipurpose use. Everything from welding to outfeed rollers on the table saw. The other thing is to use automotive jack stands. Soon as I get the back yard completed, Ill be welding up a trailer for the utility body, and Ill be doing it all on carefully leveled jackstands
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3
Reply to
Gunner
Grant, I hope you made the measurements in person...
Steve
Reply to
Steve Smith
sure did, Steve!
GWE
Reply to
Grant Erwin
"Ignoramus10273" wrote: Welding on cars, is generally discouraged due to possible electronics damage... otherwise it would be cool... ^^^^^^^^^^^^^^^^^^ The question is now moot--due to the distance from the shop to the truckbed. However, I have to take issue with your point about welding on cars--it's been discussed here before. A metal frame sitting atop a wooden truckbed would have the return clamp attached, not to the vehicle, but to the metal being welded. There would be no current patch back through the truck.
Two things have be be watched when welding on a vehicle: 1.) Don't have a return path that passes current through ball-bearings (or roller either.) Always attach the "grounding" clamp next to the weld, so current doesn't go through the vehicle's electrical system.
Reply to
Leo Lichtman
You might want to weld on some convienient loops for the come along. If they can stay there, tell your customer that these are 'features' so he has tie down places.
If nothing else, make some 2" square tabs with 1" holes from 1/8" or so stock, weld them on the top surface on ONE side of the tab. Use for tweaking, then break them off easily and a quick grinder cleanup.
Grant Erw>
Reply to
RoyJ
You need two horses or cross members over six feet long. You don't need a flat area. What you need are two cross members that are level and spaced about eight feet apart and seven feet long. Set a good spirit level ( 2 foot minimum) on the first cross member and level it with blocking or whatever you have. Level the second cross member. All you do now is set you long angles of your frame on the cross members 6 feet apart. Use clamps to secure them to your cross members. Fit your end angles (6footers) at each end and check diagonals until square. Tack in temporary bracing until welding is completed. Too much temporary bracing in an impossibility. If you have done this right your nine foot pieces are spaced properly apart but they may not be level. This is not important. What is important is that they rest on the levelled cross members. I never build frames on flat areas. It is a false assumption that things will end up right. A spirit level and diagonal measurements tell all. If you have trouble hanging the end cross pieces just clamp a scrap piece of flat bar to the end of each nine foot piece. The six foot cross piece can rest on the flat bar. I like steel horses for a job like this and if the horses are not long enough it is a simple matter to tack something longer on top. Randy
OK, I have another one-guy-in-a-small-shop problem. I've made a bunch of rectangular frames from angle iron, but this one is a little different. The legs are much larger than my welding table. My welding table is about 4x5' and this frame is about 6x9'. I do have some flat concrete floor space available but that means no clamping to a table. This frame has to be square enough to drop over an existing wooden truck flatbed.
Ideas?
Grant Erwin
Reply to
R. Zimmerman
The way I've done this kind of thing in the past is to use some right angle brackets from a steel-framed building. They're made from 3/8" plate and about 8" long. I attach them to the angle with two, or preferably four, strong G-cramps. Then I weld each joint and let it cool before I move on the the next one. I've got acceptable results doing this, but I don't know if it would be accurate enough for your job. I don't know if the angle brackets are a common item which you could buy; I got them amongst some scrap.
Best wishes,
Chris
Reply to
Christopher Tidy
Randy,
I agree about the metal sawhorses, they can be very handy. At my day job we are building alot of mezzanine and independent platform sections for a plant in Texas,(4 tractor trailer loads already, 6-8 more loads sitting in the yard). 6 sawhorses, a handful of various size shims, a transit level and a tape measure can build some pretty large platform section in just a little while. The biggest we have set up in house is 28' x 17', level within 1/32", square within 1/16", decked with 1/4" Alum. tread plate, hand rails all around, safety ladders, etc. Put it all together, tear it all apart, label, paint, palletize, ship and hope the guys on the other end like jigsaw puzzles.
Regards, Jim
Reply to
Jim C Roberts
Grant you don't need a table and you don't have to level anything. I would use 3 sawhorses, 4 pieces of scrap flat stock, and 8 clamps. Cut your pieces to length and miter the ends at 45deg's. Clamp a piece of flat stock at each corner and set the assembly on the saw horses. Use two horses at one end and one horse in the center of the opposite end. The angle iron will support itself, no table needed and does not have to be leveled. Now adjust things so that the diagonal's are equal. I would probably cut a couple pieces of 1x4 wood to the proper length to fit inside the 6' dimension and clamp them also. Then just tack things up, rechecking your diagonal's often till it is all tacked. Once that is done weld it up. Don't forget to chamfer the edge of the 1x4 that fits into the inside corner of the angle iron. Should be an easy job.
Reply to
bitternut

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