|Richard chucklbutty||23/08/2018 03:14:07|
|57 forum posts|
How would I turn the correct concave profile for a bearing cup for a bike wheel hub , how can i find out the correct radius ? and how would I hone it or polish it after hardening ?
The original race is a thin cup, but the replacement could be made from solid much thicker in depth as the pocket is flat bottomed.
|Paul Lousick||23/08/2018 04:53:18|
|1414 forum posts|
The corner radius should match the radius of the ball bearings. The inside diameter of the hub should be a running fit with the ball bearing race.
Finish turning the hub on the lathe with a radiused form tool (grind a HSS blank to suit radius) and use emery paper to smooth. Fine grit paper to finish and polish.
Edited By Paul Lousick on 23/08/2018 04:55:49
|John Haine||23/08/2018 06:22:45|
|3093 forum posts|
Surely you can just buy a replacement from a bike shop?
|Nigel Bennett||23/08/2018 09:09:38|
339 forum posts
Those of us of a certain age may recall buying replacement Campagnolo bearing races mail order from the Whiskers Catalogue. That was when you could actually go into a bike shop and buy (say) an individual pawl for the freewheel inside your five-speed "block".
At the present time, like every other supplier in the throwaway society, bicycle component manufacturers will launch new products in their range quite frequently, and asking bike shops to stock spare parts for all the ranges for (say) the last ten years for several manufacturers is not on. You wear out a hub - you buy a new hub. And count yourself lucky if it can be made to fit the spokes and rim. And if you can't do that, you buy a new wheel. Oh dear - they don't do it in 8 speed any more - you have to get an 11 speed. And by the time you've finished, it's easier to buy a new bike.
That's how it works in this day and age.
Back to the OP. You need to get a really superb finish on your HARD replacement insert. You should be able to measure the old race well enough to get near if you cut it in half. It needs to be very close to the ball diameter. Ideally you'd harden the race and then grind it to suit, but that's pretty specialist.
I'd fit ceramic balls when you've made it; they (apparently) iron out the creases in your race and it should last longer.
Edited By Nigel Bennett on 23/08/2018 09:12:37
|12 forum posts|
radus should be somewhat oversize to obtain line contact and ease of alignment when doctoring an or baliss willey the gash box turned up a pair of magneto bearings that did the job with minimal fiddling
|527 forum posts|
in case it's an odd fellow there is a family firm that will rebuild repair any old ball races and bearing....
not mad expensive...they will also hard chrome shafts and grind back to original size.......
can't find the address at the mo but they advertise in the old motorcycle magazines.......
seen their work and it brill....clogs
5216 forum posts
Oh the innocence of youth. Sounds like a lot of you have only seen modern wheels. Time was the shell in the wheel hub was a pressed in piece of pressed steel, probably not turned or ground, well hard of course. I think as Camper says you want a bigger radius. The more important question is overall diameter of the inside so that the balls rest at the right separation not quite rubbing.
|Richard chucklbutty||23/08/2018 13:55:36|
|57 forum posts|
Modern bearing cups are pressed in and not designed to be replaced, the whole hub is scrap, usually the wheel is binned as its too labour intensive to rebuild the wheel.
The high end bikes have moved on to sealed bearing units which they call " cartridge bearings" but they are still not common place. I doubt manufacturer's are happy about wheels lasting forever with just cheap drop in bearing units.
|Gordon W||23/08/2018 14:00:25|
|2011 forum posts|
I've never thought to make new races. One way to make a form would be to braze a suitable ball bearing onto a shaft, then grind a flat to half diameter. A fairly new bike I've been working on has pressed steel races, but I only go very slowly.
|428 forum posts|
Bit off topic hijack ...Nigel , tell me more about this Whiskers catalogue..! I thought it was just a bike shop in North London ?
I bought this bike down our local tip for 15 quid, and thought it looked a bit up more market than a Halfords offering.. A decal on the seat tube says Whiskers , other decals say Raleigh Special Products .
|BOB BLACKSHAW||07/09/2018 02:46:20|
|299 forum posts|
What I can remember from the early 1970s Whiskers catalogue was sheets of A4 with parts and offers.
I use to cycle there from Luton with mates from the cycling club to see what was on offer, I think that they specialized in Campagnolo, very expensive at the time but the best.
Good price for that bike Hacksaw, looks early 90s.
Edited By BOB BLACKSHAW on 07/09/2018 02:47:49
|David Davies 8||07/09/2018 07:04:47|
104 forum posts
Years ago I poored over Whisker's A4 lists and bought many Campagnolo spares from them including hub cups and cones I replaced several bearing cups in Nuevo Tipo hubs. No one could afford Record hubs! From memory their mail order address was in Goff's Oak, Herts. An American firm, Wheels Inc, make pattern Campagnolo cones, they may also supply cups to suit. Hope this may help.
|Martin Johnson 1||07/09/2018 08:45:36|
|129 forum posts|
Richard C. - your photos bring back wonderful memories of a tandeming holiday up the West coast of Scotland when we limped a bike with a very floppy back wheel up to Ballachulish. I stripped out the back wheel to find exactly what your photo shows. Enquiries revealed there was a chap up at Kinlochleven who might be able to help. A local kindly drove us there and I was less than hopeful when I saw the general store. Miracle of miracles, the part was produced from a box of bits, the shopkeeper gave us a lift back to Balachulish, some grease was scrounged from the local garage and half an hour later we were roadworthy again.
I have to tell you the shop at Kinlochleven has since shut.
If I was in your position, I would convert to a couple of sealed bearings. You might have to bush the hub and make a new axle, but I think you'll end with a better job than attempting to re-make a cup out of silver steel.
Thanks for prompting a great memory.
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.