The Chopper Compendium

I hope that as people come to the site they keep in mind that jigs and fixtures are just tools of the trade. Sometimes we build something that is relatively permanant in nature and other times we hack something together for a specific situation. When I was coming up most of the old greybeards I worked with didn't use anything at all and just layed everything out on the shop floor, having friends and onlookers stand on the varous pieces of tubing shimmed up with 2x4's or just held in some poor guys bare hands. It all seemed to work out in the end. Just keep in mind that everybody will develop their own unique ways of doing things and having a fancy welding jig doesn't means that you can build good frames or forks. Often times it's a persons techniques rather than his or her tools that determines the final product.

i agree whole heartedly very well put.

Good to see you here.

I also laid out some lines on the garage floor. Worked fine.

I have to agree with that too....very well put,they aren't needed as said.I did wind up making some temp jigs to hold my shit together.I had to have one of my sons hold the neck while I tacked it on.Not
Using a jig for the most part, I think I was a little more mindful about not spending to much time welding in a given area.I now have a couple more bikes in line to get cut up, & was really considering building a jig, but this frame came out fine.So I will just do the same on the others.....lots of measuring & taking my time.....

I intend going high tech.....tube benders jigs etc just the way I like to work....

I agree, but I use jigs because I have limited space to work and it keeps stuff neat and tidy...

Maz xx

Keep in mind that there are two distinct schools of thought about jigs and fixtures. One school submits to the concept that a jig or a fixture is merely a 'positioning' device and does not rigidly hold the tubing. The other school adheres to the concept of having the jig or fixture clamp all of the parts rigidly so they are held in place solidly with no posibility of movement. I've used both techniques and perfer the first school of thought where the person doing the welding controls any possible movement the parts may experience. Both methods work if the welder is doing his or her job but in the hands of a less experienced welder the second school of thought presents some problems. Unfortunately even the most solid and rigid of jigs doesn't actually prevent metal from shifting and moving but you don't see this displacement until you take the part out of a rigid holding fixture type of jig. It is not uncommon in large fab shops that use rigid type jigs to see people using deadblow hammers to get a part free from a fixture since they have so much built up stress. You'll hear a big 'sprong' sound as the part pops free and moves into the shape it wants to be in to equalize the stress it was under. I can go on and on about this problem but don't have the time right now but it's something that really needs to be expanded upon someday.

gww25 wrote:Keep in mind ... but it's something that really needs to be expanded upon someday.

I patiently wait for any tidbits of knowledge/experience.

(which is the "chompin-at-the-bit" smiley)

Well put. A jig will not compensate for improper technique either.
Just because your frame is in a jig doesn't mean you can just weld the piss out of
it and everything will still come out straight and true. Weld it wrong and you can actually
bend your fixture from the weld stress. Something to think about.

Some very good points and advice there guys - I always thought of my jigs as a neat and functional way of holding things still so I can position them properly and check for alignment etc - my jigs are certainly too lightweight to hold things so rigid they won't "pull" during welding...it is my responsibility as the one holding the welding torch to make sure I weld it properly.....a jig is as you so rightly say, just another tool..... but at least I painted mine to make them look pretty

Maz xx

Maz wrote: but at least I painted mine to make them look pretty

Maz xx

Sometimes I wrap my tool in pretty colored latex!

speechless

Maz xx

gary,

can you teach me about jig building? I want to know all there is to know about it. How many different jigs can you build and what would the approximate cost be to build each one?
Also frontend jigs...i saw this one cd that the old gray haired guy used wood and channel steel. What a loser.

My learing experience with jigs and weld quality/proceedure - I built a frame on a very rigid jig and sent it to powdercoat. The heat from the powdercoat cycles actually moved some of the tubing around - it actually 'stress relieved' my frame and made evident my failure to follow proper welding technique. I had to redo that frame and have stuck to the recommended techniques of tubular welding ever since. Now my frame neck jig is pretty simple and not real rigid at all and seems to work well for me.