Detecting worn Cam followers

[PJGD]

Another comment on this topic:

For a long life between overhauls (TBO), one would imagine that you would want the best surface finish on your cam lobes as is possible. To achieve this, it is necessary to traverse the wheel to & fro across the lobe. This is not possible with the angle dressed into the wheel, so to be able to do this, it would be necessary to offset the tailstock from the true axis to give you the desired angle. In the case of the Jowett camshaft the suggested 0.002" difference side-to-side of the lobe gives an angle of about 0 degrees 15 minutes. But this means that you have to move the wheel in a little bit for each lobe that you grind as you move toward the tailstock, and this can be tiresome, however it also means that you do not have to dress that angle onto the wheel — just leave it straight across as normal.

If you do use the strategy of dressing the angle onto the grinding wheel, then it means that you are obliged to plunge grind, which is OK but you will give up a little bit on surface finish and thus life.

[RichardMc]

Does someone make a CNC grinding machine? I've got a friend in Leeds with a several auto feed five axis milling machines and it seems remarkable what these things can make (he owns a medical device company). It wouldn't seem too complex to do this with a grinding wheel head instead of a cutting tool, perhaps I’ve missed something.
I'm meeting him next week so I'll ask, cost might be an issue, he didn’t get to where he is now by doing cheap car bits but you never know.

[Keith Clements]

I guess the problem is getting the grinding wheel spinning fast enough.
Also the wheel would probably need dressing regularly and the grinding fluid delivery would need sorting.

[PJGD]

Find a machine shop with Studer CNC grinders; they are the best for OD grinding

[RichardMc]

An early Christmas present arrived today, can't give too many details at the moment, I need to check it measures up as expected. It's never been used and was made in the 80's for a race engine. It came with a 'friend' that looks very similar but the shaft isn't as well machined, the second one looks cast like the original Jowett ones do (but much better finish) whereas this one looks like it may be from a billet. My informant tells me that Bill Lock may have been involved with one of them but isn’t sure which. We don’t have Cam Doctor in the UK but I do have a rotary encoder somewhere and a digital DTI so I might need to make one, or do it the hard way.
Thanks for the tip on Studer machines.

IMG_20241206_190806074_MFNR (1).jpg

[Srenner]

Never got a clear answer on any of the cams from Mr. GrumpyGrinder. He worked all the cams and sent me a bill. I will see if I can find the specs, but I expect the numbers will be close to the factory spec and not a significant change.