03-03-2022, 10:52 PM
(This post was last modified: 03-03-2022, 10:53 PM by Stuart Giles.
Edit Reason: typo
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(03-03-2022, 08:07 PM)Steve Jones Wrote: Just measured one, Ruairidh, and it was 1 1/4" x 20 tpi. Tracy Tools web site lists both taps and dies in that size- BSC Thread - but no stock of taps, only carbon dies.
Steve
I'd be surprised if that was a 20 TPI cycle thread (60 degree), more likely to be a 20 TPI WF thread I would have thought -All the other 'non standard' threads on the A7 are 55 degree WF. But, once again, Tracy tools only have stock of a carbon die in this size. If Ruairidh is just doing a 'special' oil filler tube, it might be easier (and certainly cheaper) to screwcut the thread in a lathe. A 20 TPI Whitworth tap will do as a chaser if the 'real thing' isn't available to put the finishing crest on the thread. With a milling machine as well as a lathe making a carbon tap from a piece of Silver Steel wouldn't be an impossibility in the absence of a buyable tap.