Re: [CR] drop out repair


Example: Racing:Jacques Boyer

Date: Tue, 15 Jul 2003 09:47:51 -0700 (PDT)
From: Bruce Krueger <bikebruce@yahoo.com>
Subject: Re: [CR] drop out repair
To: "Karstens, William" <wkarstens@noris.psasd.navy.mil>
In-Reply-To: <3E234FBCAB5AD61184C600C09F0656A70136094F@NORIS>
cc: classicrendezvous@bikelist.org

However, would a c clamp work just as well if not
> better? You'd be
> able to apply preasure slowly and steadily with a
> much better view of the
> area to which you're correcting. *** a (sufficiently finely) threaded press might work (lord knows park's frame press generates more than enough), but I don't know if most c-clamps have either a fine enough thread or a rigid enough frame to generate/sustain the required amount of force.

I believe vice
> grips with thier locking
> mechanism have a fulcrum point that may have a
> sudden spike in pressure. *** no idea what you're talking about -- it's true that the compound lever generates non-linear pressure, but I'm not sure where the 'spike' idea comes from. it's also true that the steel will make an excursion through the plastic range before it deforms with each successive clamping, and then return a bit as it's released, but again, I'm not aware that this is a problem (on the contrary, it allows for closer approximations to the intended configuration with less chance of over-shooting). also, the grooves in the vice grip help keep the 'jaws' of the dropout in plane, where the flat surfaces of a c-clamp (or worse, a pivoting head) would allow them to skew.

I'll grant that a special threaded tool might work as well as or better than a vice grip, but good luck convincing park to undertake development and production -- I couldn't even convince them to put a floating tip with a concave surface (sort of like what's on the cotterless crank press, only an 'innie' instead of an 'outie'..) on their cottered crank pin press, even though it would improve it an simplify use (it's prevent the tip from mushrooming and walking off the pin). when they told me how many of the tools they sell a year, though, I could kind of see their point.

bruce krueger
bikeworks
urbana IL