Internal Grinding

Hello, is there any body who could help me out, or point me in the right direction

i need four imperial needle roller bearing inner rings, the ID ground out.

Inner ring details IKO IRB1012 ID 15.88 X OD 22.23 X WIDTH 19.30

i need the ID ground out from 15.88 to 19.48

the inner rings are to fit on the ends of a 1970 Honda CB450 camshaft.

Many Thanks.

Bob Edmondson Cumbria.

Edited By JasonB on 05/07/2018 13:01:07

Hi Robert I would bore it on a lathe using a carbide tool, as it is to much material to remove with an internal grinder. Maybe flick it up on grinder if you cannot get the size correct. I thought that these camshaft ran in the alloy casting when new.

David

Bob, i am not far from you and may be able to help but if my info is good this will leave a wall thickness of only 0.054" plus that a lot of material to remove by grinding !

See the PM I sent you with contact details

John

Hi Robert I have just looked at the assembly of the camshaft and it would be simpler to fit a bush not a needle roller bearing. You would just have to bore out the castings flick up the crankshaft journals on a cylindrical grinder if it needs it and make a phosphor bronze bush to press into the casting.

David

This was a common mod on Honda singles and twins in the 1970s that came standard with the camshaft running straight in the aluminium cam support blocks. When they chewed out from poor lubrication (and merciless flogging from teenaged boys) guys used to bore out the cam blocks and fit bronze bushings. They seemed to work well. Certainly better than the original aluminium. The XR and XL 250s were quite infamous for this problem.

Seems like in later years, classic racing guys got into needle roller conversions, using bearings supplied with an oil hole in the outer race to match the original oil hole in the cam block. But the usual way seems to be to bore out the cam block to suit a larger bearing and then either sleeve or machine down the end of the camshaft to fit the bearing inner race. Lot of mucking about but easier than grinding several millimetres out of a race. You should be able to turn down the end of teh camshaft in the lathe with a carbide tool if necessary. Probably overkill for a road engine though.

Edited By Hopper on 06/07/2018 12:07:50

I would suggest you send the to Alpha bearings in Dudley, but sadly Max Nightingale passed away recently and i don't know if the company is going to continue. They certainly could have adapted the bearings for you.