Welding Jig

[bigegg]

I'm looking to build a jig so I can quickly weld up a few sets of my car ramps

Just wondering what size steel I should use for the main frame? I'm thinking something along the lines of 100mmx100mmx6mm I beam, with cross pieces of 100mmx50mm C section?

It will be to hold the frame pieces whilst the 6ftx2ft triangular sides are welded up, then an extra jig will be clamped on so that two triangular sides are held upright whilst the cross members are welded in.
Clamping and squaring each piece in turn adds about 10 hours to the job - making it uneconomical - and I have an order for six of them!

 

[bigegg]

anyone?
Is 4x4 I beam overkill for a jig to weld 50x50 Angle + box? or would a jig made of 50x50mm box be stable enough?

 

[Paul.]

For a light fabrication like that you could use pretty much the same material as the job is made from, try not to over think or over engineer it, all you need is something to hold it square while you tack it up, I would probably hand build a ramp first then build a fixture around it.

 

[bigegg]

I would probably hand build a ramp first then build a fixture around it.

Thanks - that's the plan. I did a google image search for welding jigs and they seemed to be all rotisserire style things made of heavy beams.
I was pretty sure I didn't need anything that solid and heavy.

Is there any sort of text book or website that covers designing and building welding jigs?
I've plenty of engineering/woodworking books on building jigs and fixtures - but nothing on welding.

 

[scotty41]

I use jigs alot, add some points to lever out the finished ramp, things can nip tight, also keep you cuts bang on with no gaps to fill, this stops it all pulling tight in the jig, I always try and finish as much welding as i can in the jig to avoid handling the same thing over and over again.

Keep your jig holding points near your weld points

Sometimes making a jig can take more time than making the desired amount of products, things like ramps i may make the 2 sides then jig the rest off them 2 sides, then put them together at the end.

Putting the 2 halfs together, i would lay one one side flat put the cross beams in with a square, vertical, if your bang on the other half will sit right on top. another way is just to make a jig to hold the cross beams at 90, move it to the next and so on.

Putting the bits of angle in for the car to run on, i would put the 1st one on square, make 2 little packers to position the next one, tack it and move the packers to the next one and so on. check square if they start to run out, accumulative error.

 

[Robotstar5]

Also remember to design the jig so the component can be removed after welding, don't laugh, I've seen it done!

 

[scotty41]

Or weld it to the jig, "Ive welded what"?

 

[mike 109444]

Don't forget make releasing the item easy to do with welding gloves on because you don't want to be un-gloving, finding a spanner, undoing lots of nuts etc etc. Find some quick release leaver clamps, not cheep but nor is time.

 

[Robotstar5]

Don't forget make releasing the item easy to do with welding gloves on because you don't want to be un-gloving, finding a spanner, undoing lots of nuts etc etc. Find some quick release leaver clamps, not cheep but nor is time.

Toggle clamps are the way to go