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#14611
Roger Moss
Participant

The first Scott I had was a 1928 built 1929 model 500cc TT Replica now owned by Ted Parkin
This had Timken Taper roller headstock bearings as standard
These were obviously more expensive than the bicycle type design, but far more rugged.
It is possible that the extra cost caused the use of taper roller bearings to be abandoned in the recession.
The outer “cup” was No 1730 and this has an outside diameter of 2.125″ (2 1/8″) and is still available
The inner “cone” was No 1764X which had an inner bore of 1.0625″ ( 1 1/16″”) and this has been obsolete for many years
I was offered one only old stock cone at a price of £190 and although I realise that modern commerce works on the principle of charging what the seller thinks he can get rather than what it had cost plus a fair margin of profit, I found this offensive.
So I designed and made a special holder for a current cone No 1780, which has a bore of 1.000″, so I could grind it out to 1.0625 to suit the Scott headstock stem.
I then had to change over my grinder to internal working which takes longer than most grinders and grind out the bores of two cones which tool about 2 hours each
So all in all, an expensive job, but I needed these bearings to finish the rebuild of my racer for the Anniversary meeting at Cadwell June 24-25-26
With a few extra refinements, the bike should be better than ever, although the rider is not as fit as he used to be.

This piece is to let it be known that if anybody is really stuck with this same problem, then I have a specially made holding fixture that can be used on an internal grinder to modify the 1″ bore of the 1780 cone to 1/16″ and would loan it out if it helps anyone.
I would prefer not to offer to grind out these bearings myself, as I think that a heavier machine would do the job much more quickly and cheaply

We would love to see you at Cadwell where our club has a stand for the three days.
If you do get chance to come,do bring your bike along to our stand to add to our display
Kind Regards to all.
Roger