2stroke4stroke Posted March 7, 2018 Report Share Posted March 7, 2018 On 28/02/2018 at 8:21 AM, feetupfun said: Some alloy steels have a low coefficient of friction so be careful. Mild steel or cast iron are the go for brake drums I always found it interesting/amusing that other manufacturers used chrome on cylinder bores to reduce friction (as well as increase bore life) . Bultaco used it on brake drums........... Quote Link to comment Share on other sites More sharing options...
blueflag Posted March 7, 2018 Author Report Share Posted March 7, 2018 18 minutes ago, 2stroke4stroke said: I always found it interesting/amusing that other manufacturers used chrome on cylinder bores to reduce friction (as well as increase bore life) . Bultaco used it on brake drums........... ????? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted March 7, 2018 Report Share Posted March 7, 2018 1 hour ago, 2stroke4stroke said: I always found it interesting/amusing that other manufacturers used chrome on cylinder bores to reduce friction (as well as increase bore life) . Bultaco used it on brake drums........... The brakes on my M138 Alpina (with chrome plated drums) are amazing 1 Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted March 7, 2018 Report Share Posted March 7, 2018 7 hours ago, feetupfun said: The brakes on my M138 Alpina (with chrome plated drums) are amazing I suppose I would have to concede that an almost frictionless chrome surface would not be any worse than the cast iron lined brakes on Bultacos I rode as a teenager☺ Quote Link to comment Share on other sites More sharing options...
craig10 Posted March 7, 2018 Report Share Posted March 7, 2018 Interesting bit of machining Blueflag, how tight a fit are you going for on your liner, given the different coefficients of expansion of steel / alloy? And how are you going to stop the liner from turning, just by the interference fit alone? Or with the aid of a bit of Loctite or similar? Cheers, Craig Quote Link to comment Share on other sites More sharing options...
blueflag Posted March 7, 2018 Author Report Share Posted March 7, 2018 (edited) It's got an interference fit, chill the liner and warm the hub to get it in. I can't see it getting particularly warm the way I ride! I put a little bit of loctite on the face just as belt and braces. I'm pretty happy with the way it's gone. I need to sort out some shoes, a brake rod and a new lever. Keeps me out of mischief... I know the finish has chatter by the way...? Edited March 7, 2018 by blueflag Missing information 1 Quote Link to comment Share on other sites More sharing options...
craig10 Posted March 7, 2018 Report Share Posted March 7, 2018 Great stuff Blueflag, I love this kind of work to keep the old ones going Quote Link to comment Share on other sites More sharing options...
blueflag Posted March 8, 2018 Author Report Share Posted March 8, 2018 Thanks Craig, I know what you mean mate, feel like an active historian! So much I need to learn though! Quote Link to comment Share on other sites More sharing options...
feetupfun Posted March 8, 2018 Report Share Posted March 8, 2018 5 hours ago, blueflag said: It's got an interference fit, chill the liner and warm the hub to get it in. I can't see it getting particularly warm the way I ride! I put a little bit of loctite on the face just as belt and braces. I'm pretty happy with the way it's gone. I need to sort out some shoes, a brake rod and a new lever. Keeps me out of mischief... I know the finish has chatter by the way...? Nice work. I'm also impressed that you did it all with the wheel assembled Quote Link to comment Share on other sites More sharing options...
blueflag Posted March 8, 2018 Author Report Share Posted March 8, 2018 Kind words! I remember reading about a Japanese tuner in the 70s who would skim drums true, lace up the wheels then heat them up before a final skim. In my case, it's just laziness....?? 2 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.