zazenzach

What exactly does this mean/entail? Ive been reading up on ron cooper and how he apparently didnt use jigs and instead used "free hand brazing."

BenCooper

I was taught this way. BB shell in a vice. ST and DT into the BB shell. HT and lower lug on. TT, upper lug and seat lug on. Chainstays on, run a string from dropouts around HT to check back end alignment. Seatstays on.

It's only possible with lugged frames not fillet brazed, obviously.

Andrew R Stewart 

I disagree with Ben's statement of fillet brazing not being able to do "freehand". Actually I'll go further and suggest that fillet brazing is easier to do freehand.

First what is "freehand"? To me it is brazing the entire joint out of a jig. Usually the joint geometry and placement is set with tacks and/or pins, which ARE often done with the frame/tubes held in a jig. many builders will follow this pinning/tacking step with a surface plate alignment before fully brazing the joint. This full brazing is done out of the jig, hence freehand. A tube, usually one that is not too close to the joint to be brazed, is held in a clamp loose enough to be able to be swiveled around but stays put when let go of. this way the access to the entire joint can be had and not limited by a jig's presence.

This ability to pivot and position the joint helps with both access and flow (gravity being a help to direct the filler). With Fillet building up this is especially nice to be able to do.

Now there's also establishing the frame tubes' placement without a jig. Also sometimes called freehand building. But not what I first think of. Andy.

BenCooper

Yes, I guess we're talking about slightly different things - I also fillet braze freehand out of the jig, and often with the odd things I build I have to bodge jigs anyway. But there's a difference between tacking in a jig and then taking out to braze, and doing without a jig altogether.

The old-school builder I learned from - Willy Bain, ex of Rattrays - didn't use any jigs or surface tables. His alignment equipment comprised a vice, a piece of string, an old back wheel, and a good eye.

Doing fillets out of the jig, a good rotating clamp is essential. I use a workstand, and wrap paper around the frame tube to reduce friction between the tube and the clamp - the aim is to be able to move the frame to any angle by hand. Though sometimes with big things you can't get the ideal position - I've done fillets lying on my back on the floor!

Andrew R Stewart 

Ben- I understand completely as your description is exactly how I started. I made maybe 8 frames using only a full size drawing, hand tools, a vice, string a good wheel and my eyes. Andy.