Duo

many of us will never bother spreading a frame but are quite content with how the bicycle was originally made. if i wanted a 10 speed rear end then i would buy a bicycle that was built with one. my 6 speed Trek with down shifters is going to stay that way, same with my 9 speed Fuji Touring bicycle.

machinist42

Do the bubbles play any part in this process, or could any true straight edge be used?

I'm guessing the Bottom Bracket shell is clamped in the vise longways? (Edit: That is, do the jaws of the vise engage the faced ends of the bottom bracket shell?)


Thanks for posting this. I am hundreds of miles from any Framebuilder, or rather any Framebuilder with any equipment, (of which I'm aware). I have no plans to respace any of my bikes, ever, but appreciate a rational approach (rather then crude string anchored at the wrong point) for evaluating alignment of the frames of the bikes I've acquired. Currently working on a 1972ishy Acer-Mex Carabela Profesional (sic), which is not an Cinelli SC, obviously, but pretty darn close.(The only structural difference I've discovered so far is the absence of the shim Cinelli used to reinforce the seat tube. A PO used a foot long 26.8 MTB seat pillar, deeply seated, to approximate the stiffening effect of the shim, which I find very clever.)

Next on queue is a mid-70s Cooper. I have seen photographs of him on the West Coast when he traveled there to check the alignment of the bikes he shipped. He valued precise alignment and who am I to disagree? These may be "simple machines." but I'm well aware a mm one way or the other...

And why not? I ride a lot, and much of it in treacherous circumstance. I need to be able to completely trust my "simple machine."

Lenton58 

Uhhh ... only one! ME! )))

String and callipers say my 979 is very slightly skwif. Maybe my technique is not very sophisticated, but this may explain why it likes to auto-shift, no matter what drive train I stick on it. Mind you, the Vitus earned the sobriquet 'the noodle". (The factory designated racers were pegged, watermarked and consequently stiffer.) But, the only other owner had a bad crash in the 80's. It ended his racing career, and he ended up with back trouble for decades. Anyway ... it's aluminum, and neither I nor anyone else will be moving anything. It looks straight and steers OK. In my experience, something a mm or two the wrong way may or may not make a discernible difference. In my case, I just live with it cuz I plod for fitness, relaxation and fun — or doing as I like.

Doug Fattic 

Not really, the level was a tool I could buy locally that could serve the purpose. It wasn't very expensive in Ukraine. Any true straight edge can be used.

Framebuilders put some kind of protection between the vise jaws and whatever is being clamped. If you look at my picture, you will see the vise closest to the camera has wood pieces between the jaws so whatever is being clamped is not damaged with jaw pressure. It is quite common to use copper plates (made by vise companies) that has arms that can wrap around the back of the jaws to keep it in place.

That vise was stolen by the Russians when the broke into the shop to take whatever they wanted. It is most likely in Russia now. Of course compared to the horrible things that have happened in Bucha and all of Ukraine that is a pretty small deal indeed in comparison. However getting a nice vise like that was a real effort. It was a Wilton (an American brand). I bought it at a bazaar in Kyiv about 20 years ago.

I visited Ron Cooper in Honor Park in London sometime in the 70's. I can't remember if it was when I was apprenticing at Ellis Briggs in Yorkshire or on a later trip a couple of years later. He didn't have a big table but rather used a long piece of angle iron. One side of the angle makes it possible to clamp in a vise. On one end was a bottom bracket shell holder and on the other end was a pre-adjusted screw. The frame would rotate on the BB holder and the end of the screw should just touch the top of both the seat tube and down tube. If not, the frame was bent until the screw just touched.

His method is a decent and somewhat inexpensive way for an occasional alignment. There would need to be some lathe work in making the BB holder. Or just grind the threads off of BB cups and somehow use those to position and bolt the frame to the angle iron.

bamboobike4

No one said there'd be French....

Doug Fattic 

Your question is outside of my knowledge base. I know some amateur builders use a Wixey angle finder for setting a fixture but I have never owned one myself. My guess is that the readouts would be a little vague for alignment accuracy (at least for my liking).

I've heard of people using laser lights somehow. The top of a table saw can work great for checking the front triangle. Counter tops have been pressed into revive. One of my butcher block work benches probably has roughly enough accuracy for the not particular. I have several long steel rulers that would work with a short 6" ruler clamped to it.

I'll attach a couple of pictures of a framebuilding class student from England checking alignment with a homemade tool we use in Ukraine. It is a square piece of aluminum with a chunk of 80/20 aluminum extrusion stuck in the end to hold an adjustable screw. This kind of tool for checking rear dropouts only works if the front triangle is aligned. If if it leaning over to one side it will give you a false reading on the rear dropouts being centered

centering the rear dropouts with a straight edge while building a frame



adjustable screw detail
.

bark_eater 

Thanks for the response. I've played with a Wixey a bit and so far its helped to find problems. I have identified a couple frames with it that need tweeking but so far I've resisted taking a 2x4 to them.

I'm assuming that the your photo shows a "flip-flop" tool where you check off both sides of the seat and head tube. Or am I missing something?

Doug Fattic 

Yes you are right about using a straight edge as a "flip-flop" tool. The adjuster screw is set on one side to just touch the inside of the dropout and then switched to the other side to see if it just touches the other dropout. It is fairly easy to place the straight edge against a lug on one side and not the other so some care has to be done to make sure the position of the SE is identically placed on both sides.

John E

Been there ... done that. Peugeot UO-8, 120 to 123 to take an ultra-6 Shimano freewheel -- works like a champ.

1959 Capo, 120 to 126 to take a standard-6 Regina America freewheel -- also works just fine.
When I had it repainted at CyclArt, Jim double-checked my rear triangle and dropout alignment.

Schwinn mountain bike -- I need only about 1 additional mm of OLD to accommodate my current 8-speed cassette, so the frame gets slightly splayed whenever I insert the wheel, and springs back whenever I remove it. No biggie. The bike was spec'd 3x6, but I bought it used with a 3x7 freewheel and subsequently substituted my current 8-speed cassette rear wheel.