I need to straighten out Stella
02-21-19, 07:41 PM
#1
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Thread Starter
I need to straighten out Stella
I've been working on a parts bin fixed gear build with a Stella SX-73 frame I bought a while back. It passed the string test (after some adjustment) and my rear wheel is properly dished. However, with the wheel in place, the rim is off center at the brake bridge. When I sight up the stays from the dropouts toward the seat cluster, I can see that the drive side stay is a bit bowed out, and the NDS has the opposite problem, and measuring from the stays to rim, there's a difference of 6.5 mm between the two sides. A side collision of some sort, I suppose. The paint all looks, well, no worse than the rest of the bike. I am not at all worried about the integrity of the frame; I just want to bend it back.
So here's my plan, and please holler at me if you think it unwise.
I don't have a frame table, but I do have a workbench and plenty of wood clamps. My plan is to lay the bike on its side with the bowed side facing up. I can make some hardwood blocks to cradle the seat end of the NDS seat stay, and the bottom of the stay will rest on the skewer end, as I'll be leaving the wheel in place to block the dropouts. Or maybe I should put a block under that end of the stay as well, so I'm leaving the dropout alone. So essentially the two stays and brake bridge will be isolated. Then, I'll put a contoured block directly over the brake bridge, and run a pipe clamp from that to the bottom of the bench top. Then, crank the clamp until I coerce the stays back into their proper place.
So....good idea? Bad idea? Am I likely to break the brazing at the seat cluster? I would really rather not do that.
So here's my plan, and please holler at me if you think it unwise.
I don't have a frame table, but I do have a workbench and plenty of wood clamps. My plan is to lay the bike on its side with the bowed side facing up. I can make some hardwood blocks to cradle the seat end of the NDS seat stay, and the bottom of the stay will rest on the skewer end, as I'll be leaving the wheel in place to block the dropouts. Or maybe I should put a block under that end of the stay as well, so I'm leaving the dropout alone. So essentially the two stays and brake bridge will be isolated. Then, I'll put a contoured block directly over the brake bridge, and run a pipe clamp from that to the bottom of the bench top. Then, crank the clamp until I coerce the stays back into their proper place.
So....good idea? Bad idea? Am I likely to break the brazing at the seat cluster? I would really rather not do that.
02-21-19, 08:14 PM
#3
feros ferio
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You should be OK, as long as you work slowly and methodically. I have cold-set lots of frames, either for alignment purposes or to accept a longer-than-OEM rear axle.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
02-21-19, 08:15 PM
#4
feros ferio
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Posts: 21,793
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__________________
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
02-21-19, 08:22 PM
#5
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02-21-19, 08:58 PM
#6
Mr. Anachronism
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"My only true wisdom is in knowing I have none" -Socrates
02-21-19, 09:11 PM
#7
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02-21-19, 09:18 PM
#8
Friendship is Magic
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Not certain how you intend to secure the block of wood.
02-21-19, 09:30 PM
#9
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I've been working on a parts bin fixed gear build with a Stella SX-73 frame I bought a while back. It passed the string test (after some adjustment) and my rear wheel is properly dished. However, with the wheel in place, the rim is off center at the brake bridge. When I sight up the stays from the dropouts toward the seat cluster, I can see that the drive side stay is a bit bowed out, and the NDS has the opposite problem, and measuring from the stays to rim, there's a difference of 6.5 mm between the two sides. A side collision of some sort, I suppose. The paint all looks, well, no worse than the rest of the bike. I am not at all worried about the integrity of the frame; I just want to bend it back.
So here's my plan, and please holler at me if you think it unwise.
I don't have a frame table, but I do have a workbench and plenty of wood clamps. My plan is to lay the bike on its side with the bowed side facing up. I can make some hardwood blocks to cradle the seat end of the NDS seat stay, and the bottom of the stay will rest on the skewer end, as I'll be leaving the wheel in place to block the dropouts. Or maybe I should put a block under that end of the stay as well, so I'm leaving the dropout alone. So essentially the two stays and brake bridge will be isolated. Then, I'll put a contoured block directly over the brake bridge, and run a pipe clamp from that to the bottom of the bench top. Then, crank the clamp until I coerce the stays back into their proper place.
So....good idea? Bad idea? Am I likely to break the brazing at the seat cluster? I would really rather not do that.
So here's my plan, and please holler at me if you think it unwise.
I don't have a frame table, but I do have a workbench and plenty of wood clamps. My plan is to lay the bike on its side with the bowed side facing up. I can make some hardwood blocks to cradle the seat end of the NDS seat stay, and the bottom of the stay will rest on the skewer end, as I'll be leaving the wheel in place to block the dropouts. Or maybe I should put a block under that end of the stay as well, so I'm leaving the dropout alone. So essentially the two stays and brake bridge will be isolated. Then, I'll put a contoured block directly over the brake bridge, and run a pipe clamp from that to the bottom of the bench top. Then, crank the clamp until I coerce the stays back into their proper place.
So....good idea? Bad idea? Am I likely to break the brazing at the seat cluster? I would really rather not do that.
I have a Zeus Competition that came that way. I managed to find one place where the wheel can sit in the dropouts where the wheel centers at the top withthe brake bridge...so try fiddling around with your wheel placement before you start bending things. IME, seat stays are relatively difficult to bend and align in the manner you propose. Not saying it can't and shouldn't be done. Just exploratory analysis of the position and alignment of the dropouts needs to be done before you start in trying to straighten stuff that might have been a little curved at time of manufacture.
02-21-19, 09:41 PM
#10
Senior Member
Thread Starter
...you don't need a whole hub. If you don't have one, you can just take a nutted axle of the proper diameter and double nut it on each side, one nut inside each dropout, and one nut outside each dropout. Working a frame to pull it back into plane is a lot easier without the wheel in place, because the rim and spokes always seem to be in the way when you want to grab or pry something.
Not certain how you intend to secure the block of wood.
Not certain how you intend to secure the block of wood.
I will also take your other advice and do some more scoping before anything else. I can clearly see that the seat stays are curved. Whether they were assembled that way, or were initially straight and later met some trauma, I can’t say.
02-21-19, 09:54 PM
#11
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...just remember that your goal is to get the dropout openings level with each other and parallel if possible, and spaced at 120. If you can set the frame up level on something, then maybe extend a piece of allthread through both dropouts and put a level on that, It might give you some hints which way to go. My instinct is to say that straightening one of the seat stays (to lengthen it and lower that side's dropout) is what you might end up doing.
02-21-19, 10:38 PM
#12
Senior Member
We only had to bend one side of the chainstay straight to get it back in alignment. we had a hub in the dropouts to keep our spacing. Slow and controlled is what it takes.
02-22-19, 01:02 PM
#13
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Thread Starter
I took another look, and held a straightedge against both stays. They were clearly bowed out toward the drive side. So I went ahead with the repair. Super easy and worked like a charm.
02-22-19, 01:24 PM
#15
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SWEET STRAIGHTENED STELLA STEEL!!! 
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02-22-19, 02:17 PM
#16
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Good job! I am impressed.
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02-22-19, 02:42 PM
#17
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Awesome another vintage bike saved! and a Stella at that!
02-22-19, 02:55 PM
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Good job.
as with most things , if you think it through first and then take things one step at a time almost anything is possible.
I had a bike recently that had an outward bow on the drive side seat stay . I did pretty much what you did and was successful .
Like you I have a wood shop and plenty of clamps. (I especially like the Jorgesen Clamps to hold the frame upright when desired. )
One thing I have found is that not all frames are the same stiffness. Some you really have to muscle and some move very easily.
as with most things , if you think it through first and then take things one step at a time almost anything is possible.
I had a bike recently that had an outward bow on the drive side seat stay . I did pretty much what you did and was successful .
Like you I have a wood shop and plenty of clamps. (I especially like the Jorgesen Clamps to hold the frame upright when desired. )
One thing I have found is that not all frames are the same stiffness. Some you really have to muscle and some move very easily.
02-22-19, 03:08 PM
#19
Senior Member
Thread Starter
Good job.
as with most things , if you think it through first and then take things one step at a time almost anything is possible.
I had a bike recently that had an outward bow on the drive side seat stay . I did pretty much what you did and was successful .
Like you I have a wood shop and plenty of clamps. (I especially like the Jorgesen Clamps to hold the frame upright when desired. )
One thing I have found is that not all frames are the same stiffness. Some you really have to muscle and some move very easily.
as with most things , if you think it through first and then take things one step at a time almost anything is possible.
I had a bike recently that had an outward bow on the drive side seat stay . I did pretty much what you did and was successful .
Like you I have a wood shop and plenty of clamps. (I especially like the Jorgesen Clamps to hold the frame upright when desired. )
One thing I have found is that not all frames are the same stiffness. Some you really have to muscle and some move very easily.
I knew I had 6.5mm difference side to side, so I only needed to move the bridge by 3.25 mm. I took a scrap strip of wood, and marked a reference mark across it and the block under the clamp. Then another mark on the strip 3.25 mm away for a target. Then it was just an iterative process of cranking the clamp, releasing the tension, checking the mark, etc until I hit the target. Took about 3 tries.
02-22-19, 07:33 PM
#21
Senior Member
Now, try that with a graphite frame. 
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