Jeff Smith Posted April 23, 2018 Share Posted April 23, 2018 I had asked this question on a related thread but it was probably masked in the thread title. Anyway I am having trouble figuring out how to attach the eccentric cranks onto the Gibson crank pins. I believe they are steel and do not seem to solder well. I have tried putting a nut on tightly and then soldering the crank onto the reduced outer diameter but I think the nuts are also steel so did not have much luck - also the nut came loose. This is the first time I have had to fit eccentric cranks - I guess easy on Romford brass crank pins. How do others solve this problem? Link to post Share on other sites More sharing options...
pete55 Posted April 23, 2018 Share Posted April 23, 2018 I tap the return crank 14BA, and screw it onto the Gibson crankpin, and when happy with position etc, undo it a little, introduce a minute drop of Loctite, and re tighten to the desired angle. Usually I use the Gibson brass casting for this part - Gibson casting 4M822. Link to post Share on other sites More sharing options...
Jeff Smith Posted April 25, 2018 Author Share Posted April 25, 2018 Pete, thanks, unfortunately I don't have a 14BA tab (not much chance of getting one here either) so I think I will screw on the nut and superglue to the crank pin then glue the crank to the smaller diameter of the nut. Link to post Share on other sites More sharing options...
RMweb Premium Michael Edge Posted April 25, 2018 RMweb Premium Share Posted April 25, 2018 I use Romford crankpins in Gibson wheels, drill and tap them 10BA. 1 Link to post Share on other sites More sharing options...
Jeff Smith Posted April 26, 2018 Author Share Posted April 26, 2018 Gibson references the crank pins as M1/14BA. Am I to assume that at that small size the differences are not noticeable? E.g. tooth angle, TPI, diameters? Link to post Share on other sites More sharing options...
drduncan Posted April 26, 2018 Share Posted April 26, 2018 I use a 1mm tap for the Gibson return/eccentric cranks which I bought cheaply on eBay. Duncan Link to post Share on other sites More sharing options...
Jeff Smith Posted April 29, 2018 Author Share Posted April 29, 2018 M1 taps from US sources on line are $30 odd. Ordered 2 from China on EBay for $1 each with $5 shipping......unbelievable! Link to post Share on other sites More sharing options...
Jeff Smith Posted July 24, 2018 Author Share Posted July 24, 2018 I tap the return crank 14BA, and screw it onto the Gibson crankpin, and when happy with position etc, undo it a little, introduce a minute drop of Loctite, and re tighten to the desired angle. Usually I use the Gibson brass casting for this part - Gibson casting 4M822. M1 taps from US sources on line are $30 odd. Ordered 2 from China on EBay for $1 each with $5 shipping......unbelievable! Just a follow on. Received a couple of cast Gibson cranks and tapped them with my super cheap eBay taps. Seems to do the job. Thanks for all the help - now if I can just get the rest of the motion to work....... Link to post Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now