Jigless Frame Construction

[RspinnaKing]

Salonistas,

This is my first post, so thanks for hosting me. I'm a Southern boy who left his heart in the wilds of Oregon and currently makes his home in the Upper Valley region of Vermont. I hope to make valuable contributions to this forum where my skills and experience allow but I'll likely be doing more listening than talking. That's how my momma raised me.

Here's the skinny. I'm currently designing and spec'ing my third and fourth frames but will be constructing these bikes with a much more spartan (or stone age) selection of tooling than what I used in the past. My first two frames were built in the shop of a good framebuilder friend back West who graciously lent me the use of his jig, horizontal mill, lathe, alignment table and other tools along with his insight, advice and feedback. Knowing that I wouldn't likely have access to a jig here in Vermont, I got the idea in my head that I'd build these bikes by referencing a full-scale drawing for miter lengths & angles, pinning the lugged joints before brazing, working slowly and carefully while doing my best to keep the whole works in phase and alignment. I'm rich in time but not dollars and am excited about the idea of building these two bikes as a tribute to the old ways to gain a deeper connection to the craft and greater appreciation for the efficiency and precision offered by modern tools and machines. Am I a fool with too much time on his hands who has let his idealism get the better of him? Maybe, but that's not the point.

The point is, I'd love to hear any thoughts or advice this forum has to offer on my plans. Any tips, tricks or insights into the joys or pitfalls of building bikes without a jig are welcome. I'll need some kind of alignment system and am considering saving for a fork jig of some kind to help keep that critical assembly straight. Are there any other helpful tools or techniques that will make the process smoother or more precise? Keep in mind that I'm funding this endeavor with part-time work at a local bike shop and other freelance work, so I'll likely have a tough enough time affording materials and won't have much of a budget for expensive tools or shop fixtures.

Thanks in advance to anyone who has taken the time to read this far and offer feedback. I'm currently in the drawing-board phase but will offer photos of the process as these bikes start to take shape.

Cheers,

Ryan King

theflyingarrow.wordpress.com
Flickr: RSpinnaKing's Photostream

[Rich Beaudoin]

I built several jig-free frames that are straight and sound by using string, a level, straight wheels and my eyes.
Your eyes can see very fine alignment problems. I have done at least a dozen lugged forks and a couple of lugged stems without a jig and they are excellent. In fact, my only real alignment problems to date on over 20 frames were the result of relying on my jig to be correct, then finding out the HT holder on my jig was slightly off. It took several frames having their HTs slightly off vertical before I figured it out and fixed the jig. Jigs can be a crutch.
Also, never be in a hurry!

[Jim N]

Some inspiration:


Tools- BB/ST Brazing Jig by bikesbystewart, on Flickr


My jig by jimn, on Flickr


rear triangle "jig" by adam benjamin, on Flickr

[ScottB]

I built my first three frames using a variation of this method from Little Fish Bicycles.

[Will Outlaw]

A couple bits of angle, some threaded rod for a dummy axle then some quality time with the string, a ruler and a tape measure can get a nicely straight rear end with all the important bits (wheelbase, bb drop, etc...) in the proper places. Total investment, about 10 bucks.

554368_3662005987362_1611332323_n.jpg

Personally, I think it's really neat to build a decent frame with nothing more than string, sky, ruler, angle finder, an ad-hoc jig and lots of patience. But then, that's all I know. :-)

[Jake Rosenfeld]

554368_3662005987362_1611332323_n.jpg

That is fabulous

[Mtblucas]

Personally, I think it's really neat to build a decent frame with nothing more than string, sky, ruler, angle finder, an ad-hoc jig and lots of patience. But then, that's all I know. :-)

So with this method why do you need the string? Are you going from one dropout up around the head tube and back to the other dropout, then measuring the distance to the string on either side of the seat tube? I would think the angled steel would render that unnecessary. Are you using the string in any other way?

[bencooper]

I learned to build from a very old-school framebuilder who didn't believe in jigs or tooling or any of this modern rubbish - he built a frame with a vice and a piece of string. DT and ST brazed into the BB shell, braze the HT to lower lug, then braze to DT, then TT. Chainstays in, then seatstays. Using the string from dropouts around the head tube to check alignment, basically eyeballing everything else.

[Andrew R Stewart]

IMG_1062.jpgIMG_1065.jpgReally all these methods are JIGGED. Just using a jig that we agree to call something else. Having said that here's a couple of shots of fork and rear triangle set ups that i have used in the past. Andy.

[david]

i have a very nice frame built by a guy named cooper who reputedly did not use jigs, etc.
maybe it's inthe blood?

I learned to build from a very old-school framebuilder who didn't believe in jigs or tooling or any of this modern rubbish - he built a frame with a vice and a piece of string. DT and ST brazed into the BB shell, braze the HT to lower lug, then braze to DT, then TT. Chainstays in, then seatstays. Using the string from dropouts around the head tube to check alignment, basically eyeballing everything else.