Re: [TheThinkTank] Tricks of the Trade- unbending an axle
Many, many efforts have shown a soft-faced, deadblow hammer is a very useful tool for straightening solid axles, ala '70s vint Schwinns, while in the hub. QR axles w/ freewheels can often be straightened, though occasionally fail. In my experience, the bearing races and cones have shown no effect from the blows. In fact, this is why we now have cassettes, the drive side bearing (fulcrum) of the axle is further inboard with a FW, as opposed to a cassette, creating a longer lever (bearing to dropout) with more force.
I have found through hundreds of trials that solid unhardened steel bent, 20 degrees or less, can almost always be cold set (unbent), once, with virtually no repercussions. This applies to forks, cranks, axles, dropouts, etc. Other metals, hollowforms and repeated bending are possible, but face limitations too complex to describe, quickly. And, of course, all bending affects the strength/toughness making the material progressively weaker.
The hammer is the first and most useful tool, though you'll need glass to make sure things are straight.
Kevin The Bicycle Collective
On Wed, Oct 24, 2012 at 9:19 AM, christopher@holisticcycles.com wrote:
Food for thought: If I see the earth as flat, I solve how the sun and moons movement through the sky in a very different way then if I believe the earth is curved like a beer can or round like a ball. The same applies to the problem solving on bicycles. If you believe Cables, Spokes, and Chains stretch, (Because you see they get longer) then you solve the problem with flat earth methods. If you know how each of these get longer then you can formulate solid solutions, communicate to customers more effectively, and take care of cyclist needs better.
Bolts do stretch! Cables will stretch when you can push a shift lever with 300 pounds of force, chains will stretch when you can put 2000 pounds of force into a crank arm with out breaking off the pedal, or sheering the chainring bolts, spokes will stretch when you have a 1/4 thick steel rim that the nipples can not pull through. All current steel, aluminum and carbon rims will allow the spoke nipple to pull through the hole before the spokes reach stretching force. So how do cables, chains and spokes get longer????
More importantly, how do we prepare bikes, and cyclist so that bicycles need fewer adjustments and last longer? If you are willing to explore beliefs, test your hypothesis, and come up with solid evidence, Then you are ready to see the bicycle mechanics world in more complex way.
Send me a note,
Christopher Wallace Bicycle Guild 773 490 0683
Thethinktank mailing list Thethinktank@lists.bikecollectives.org To unsubscribe, send a blank email to TheThinkTank-leave@bikecollectives.org To manage your subscription, plase visit:
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Sure they Park manual says that you cannot unbend an axle. And yes, working at a shop you wouldn't do that without customer permission (and maybe not even then), you'd just order a $10 axle from Wheels.
Since we have plenty of "clients" who could care less about the "right" way....Have fun trying to rebend a beefy 10mm rear axle with a hammer (small sledge maybe?) - if you're happy with the result and it works well, there are much worse things we could do the "wrong" way.
My "wrong way" example might be - replacing hub bearings with ones which "look like" the right size from the bearing bucket. Have you ever dropped those through the park ruler bearing holes? Ten brand new bearings (of known equal size!) costs about 25 cents in bulk.
Side note - some bike folk once advised me that it's not always best to use the high grade super-hard bearings, since some lower quality hubs don't tolerate them quite as well as softer bearings. Not sure I buy this in a practical sense or will ever know, but there it is...
Side note - Loose Screws is going out of business, they want to retire. <Sad face> They were nice enough to give my last collective a discount on bulk bearings. Might be an opportunity to work with them for spare parts for our community??
Brian
On Wed, Oct 24, 2012 at 10:36 AM, Kevin Dwyer kevidwyer@gmail.com wrote:
Many, many efforts have shown a soft-faced, deadblow hammer is a very useful tool for straightening solid axles, ala '70s vint Schwinns, while in the hub. QR axles w/ freewheels can often be straightened, though occasionally fail. In my experience, the bearing races and cones have shown no effect from the blows. In fact, this is why we now have cassettes, the drive side bearing (fulcrum) of the axle is further inboard with a FW, as opposed to a cassette, creating a longer lever (bearing to dropout) with more force.
I have found through hundreds of trials that solid unhardened steel bent, 20 degrees or less, can almost always be cold set (unbent), once, with virtually no repercussions. This applies to forks, cranks, axles, dropouts, etc. Other metals, hollowforms and repeated bending are possible, but face limitations too complex to describe, quickly. And, of course, all bending affects the strength/toughness making the material progressively weaker.
The hammer is the first and most useful tool, though you'll need glass to make sure things are straight.
Kevin The Bicycle Collective
On Wed, Oct 24, 2012 at 9:19 AM, christopher@holisticcycles.com wrote:
Food for thought: If I see the earth as flat, I solve how the sun and moons movement through the sky in a very different way then if I believe the earth is curved like a beer can or round like a ball. The same applies to the problem solving on bicycles. If you believe Cables, Spokes, and Chains stretch, (Because you see they get longer) then you solve the problem with flat earth methods. If you know how each of these get longer then you can formulate solid solutions, communicate to customers more effectively, and take care of cyclist needs better.
Bolts do stretch! Cables will stretch when you can push a shift lever with 300 pounds of force, chains will stretch when you can put 2000 pounds of force into a crank arm with out breaking off the pedal, or sheering the chainring bolts, spokes will stretch when you have a 1/4 thick steel rim that the nipples can not pull through. All current steel, aluminum and carbon rims will allow the spoke nipple to pull through the hole before the spokes reach stretching force. So how do cables, chains and spokes get longer????
More importantly, how do we prepare bikes, and cyclist so that bicycles need fewer adjustments and last longer? If you are willing to explore beliefs, test your hypothesis, and come up with solid evidence, Then you are ready to see the bicycle mechanics world in more complex way.
Send me a note,
Christopher Wallace Bicycle Guild 773 490 0683
Thethinktank mailing list Thethinktank@lists.bikecollectives.org To unsubscribe, send a blank email to TheThinkTank-leave@bikecollectives.org To manage your subscription, plase visit:
http://lists.bikecollectives.org/listinfo.cgi/thethinktank-bikecollectives.o...
Thethinktank mailing list Thethinktank@lists.bikecollectives.org To unsubscribe, send a blank email to TheThinkTank-leave@bikecollectives.org To manage your subscription, plase visit:
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participants (3)
-
Brian (SLO Bike Kitchen) -
christopher＠holisticcycles.com -
Kevin Dwyer