Work holding angle iron into cube

[Whiskeymike]

Newbie question... i’m making a cube from 1” angle about 3’x4’ to hold a squirrel cage fan to make an air filter. Planning to notch the ends so they fit up nicely.

What’s the best way to clamp this together for welding and keep the corners square? I have vise grips, c-clamps, pipe clamps, squares, magnet squares, etc..

I planned to do the bottom rectangle, uprights, then flip over to do the top. Tack everything, make sure it’s good, fix any out of squareness, then finish welding, then clean up.

 

[AMCguy]

Assuming you have a perfectly flat surface to work on...

Square up your first corner, clamp it securely and then weld it entirely. Then move to an adjacent corner and do the same.

If you try tacking the whole thing together, even if you get it all nice and square, by the time you're finished final welding it will be all over the place.

Glenn

 

[Ole Slewfoot]

Square up a corner and tack in a diagonal brace if you don't have one o them fancy clamp tables. Knock the braces out later.

 

[matt_i]

How I would roll with this is to make up some rectangles, starting with one angle and then adding to it. Use the plane of the table and a reference square. Apply lightest tack that will hold the material together to be gently handled and flipped over. Tack that side. Now roll back and forth alternating tacks on each side, and checking plane and square along the way. If you don't like what's going on, apply more tacks to the side that needs to be "pulled", noting that this won't correct gross errors, only slight ones. Once you have about 3-4 "hotter" tacks per side depending on weld length then its time to dial up the heat and finish it off. That number of tacks seems to be able to resist the stress of a couple inches of weld. Note I don't have an exotic clamping setup, its just a steel table and if I do clamp its with a magswitch right angle block just for placing the original tacks.

I'd build two rectangles, and then clamp those to the plane, apply 2 cross-bars, work on those, and then flip over.

 

[joe49]

Buy a welding table and a bunch of clamps and fixtures.......
Or just use one of the methods already described.

 

[Whiskeymike]

Good info. Thanks guys. I have a 4x4 welding table with 1/2” top. But it isn’t the fancy fixture type. I can do a square rectangle. But the uprights and the flip side of the cube had me concerned. I’ll make some right angle triangles and braces and try the techniques you guys mentioned.

 

[BD1]

Ideally a BESSEY angle welders clamp would be my choice. You can get knockoffs reasonably priced. For the frame setting on table tack angles to table to for a ninety thats square, and clamp frame to it. The welders angle clamps are a great investment if you will have work for them.
https://www.amazon.com/s/?ie=UTF8&k...qmt=b&hvbmt=bb&hvdev=c&ref=pd_sl_4jmv1ji4z3_b

https://www.amazon.com/dp/B0006694FA/?tag=atomicindus08-20

 

[Firstram]

I work in the film business and we build cubes around almost everything for portability. Sounds like you have the perfect table for this project.

You didn't list the height of the cube so, lets call those legs. I would start with the 3' x 4' T&B. Cut and cope both sets of parts and place the bottom rectangle on the table roughly centered. Tack 1 long side to the table to hold it in place (clamps will be in the way). Be sure to tack the outside edges so you can cut the finished product free. Get frame close to square and loosely tack it together but, keep the tacks near the bottom edge. Measure both diagonals and shift the other long side to get the frame square and clamp down.

Stoop down and sight across the long sides to make sure they're in the same plane, shim as needed. This will/can compensate for a table that's not flat (Google Winding Sticks). Once flat and square, tack the other side to the table and weld it out skipping around to minimize distortion.

Clamp or tack the top frame aligned to the bottom frame with the parts oriented like they will live. With angle iron that will be leg down. Weld it out in place and let it cool, which will give you T&B frames that line up perfectly. I usually weld a reference dot on each frame on one corner to keep them oriented. Pull the top frame off and set aside but leave the bottom tacked down.

When I'm building more than one cube, I use the lower frame as a fixture and weld out all of those frames for consistency (always marking the same corner).

Now stand the legs in place but, lean them in slightly and put a healthy tack on the outside corner. This will allow you to adjust the frame to square it up. Have someone help set the top on the legs with the reference marks aligned (leaving a slight gap) and put a healthy tack on the outside corner.

Using a tape measure, square each side and brace diagonally. I tack turnbuckles in the corners so that I can adjust as I go. If you don't have any use scrap steel.





Once everything measures square, walk around several times and eyeball the sides to verify everything planes out. When you weld it out, always place welds in pairs that will contract with opposite forces to minimize distortion.

I know this has been long winded but it's difficult to describe. Squares, magnets and fancy fixtures are often overrated. A tape measure and a good eye is all you need to build a cube that doesn't rock and roll all over the floor. Best of luck

 

[Whiskeymike]

Wow, that’s genius. Thanks for taking the time to write it up. It makes a lot of sense.

 

[BD1]

Assorted squares of types and sizes make fabricating easy. I can see neglecting a level but not squares.

 

[Firstram]

Assorted squares of types and sizes make fabricating easy. I can see neglecting a level but not squares.

A 3' x 4' rectangle will always have a diagonal of 5'. A square can only be trusted to extend a line or a part out to a reasonable distance. If I was building something fairly small I'd reach for one of my many squares. If it's something more than a few feet and the sides are parallel, measuring diagonals will always be more accurate.

 

[Firstram]

How I would roll with this is to make up some rectangles, starting with one angle and then adding to it. Use the plane of the table and a reference square. Apply lightest tack that will hold the material together to be gently handled and flipped over. Tack that side. Now roll back and forth alternating tacks on each side, and checking plane and square along the way. If you don't like what's going on, apply more tacks to the side that needs to be "pulled", noting that this won't correct gross errors, only slight ones. Once you have about 3-4 "hotter" tacks per side depending on weld length then its time to dial up the heat and finish it off. That number of tacks seems to be able to resist the stress of a couple inches of weld. Note I don't have an exotic clamping setup, its just a steel table and if I do clamp its with a magswitch right angle block just for placing the original tacks.

I'd build two rectangles, and then clamp those to the plane, apply 2 cross-bars, work on those, and then flip over.

All excellent points on how to tack up and use the welder to true up the work as you go!

 

[BD1]

A 3' x 4' rectangle will always have a diagonal of 5'. A square can only be trusted to extend a line or a part out to a reasonable distance. If I was building something fairly small I'd reach for one of my many squares. If it's something more than a few feet and the sides are parallel, measuring diagonals will always be more accurate.

You did a wonderful job of explaining it. Three, four, five Should be basic knowledge for any square layout. The same as six, eight, ten. A pair of basic carpenter framing squares 18" x 24" would work perfect.