I just read Sheldon's stuff and it is pretty good, except I think the part about installing pins leaves out a few things.
Of course you have to obtain cotters that are the correct diameter and the approximate correct cut angle. These days choices are very limited but in the "old days" we had cotters of many varieties... Buy a bunch as they are relatively cheap.
And understand the desirable result of cotter fitting: - after you are all done, you want plenty of available threading for the nut and asher (both essential). - you want a fairly full interface between the crank slot facing and the cotter cut angle. (this step is why filing is necessary.)
Once you are satisfied that the pin you have bought is appropriate for the job, try a test fit. Hopefully the cotter will not go too far in, still allowing room, after filing, to be close to the final position. I used a magic marker (felt tip marker) and coat the face of the cotter's cut angle. Then insert again and tap gently so the cotter will contact that flat of the crank surface. Then remove and observe where the markings were smudged of squished away; now start filing the cotter, focusing on the high spots that the marker ink was removed.
I clamp the cotter in the soft jaws (brass?) vise with the cut flat up and parallel to the ground. Sheldon talks about rocking when filing which is a risk, so use 90 degree opposing strokes too, this will help keep the filed face flat.
Once you are satisfied that the flat angle of the cotter is close to the angle at it's contact with the crank flat, you are ready to install.
I use a 2" x 4" piece of wood, square cut to a length just maybe 2"? longer that the bb height of the bike. Drill an approx? 1/2" hole (doesn't have to be deep) in one end. Place that hole under the crank, threaded end of cotter in the hole. then use a hammer to gently tap the cotter into the crank arm. No huge smashes, just darn snappy small whacks to ramp up the interfaces.... Use nut and washer to secure it all together not tightening those too tight... Check the nut for tightness after the first ride and again a number times in the first weeks of use...
Dale Brown cycles de ORO Bike Shop 1410 Mill Street Greensboro, North Carolina 27408 USA 336-274-5959 http://cyclesdeoro.com http://www.classicrendezvous.com http://www.carolinacup.com http://www.greensborovelo.com http://www.bikegso.org http://nbda.com
-----Original Message----- From: ryan hildebrand <greengate@gmail.com> To: classicrendezvous@bikelist.org Sent: Wed, 13 Aug 2008 3:12 pm Subject: [CR]Questions on replacing crank cotters
I see that Harris Cyclery sells replacement cotters and advises that
8.5 mm cotters will fit most Italian cranks. Does anyone have
experience using these cotters with a ca. 1960 Magistroni crank set?
How is the fit? How much filling is necessary? How difficult is the
installation? Is a press absolutely necessary (keep in mind I've not
serviced cottered cranks before)? Any advice, anecdotes, or
recommended reading beyond Sheldon's excellent articles
(http://sheldonbrown.com/cotters.html and
http://sheldonbrown.com/
If you live in Southern California and wouldn't mind showing a newbie how it's done, please get in touch.
Thanks,
Ryan Hildebrand
Costa Mesa, Calif. USA