Re: TPI discrepancy
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Has whoever sold you the lathe kindly supplied a metric transposing gear (127 teeth) in the train under the cover on the left hand side? Check the tooth counts for all the gears from spindle to gearbox input and see if they match what is in the catalogue. There might be a listing somewhere in the files section.
I take it your leadscrew has an Imperial rather than metric pitch? Worth a check.
On Sunday, 26 July 2020, 19:46:42 BST, Michael R via groups.io <reflexermr@...> wrote:
I'm threading a backplate for the Jacobs collet chuck. The spindle is 8 tpi. I've checked that the gearbox levers are in the correct position and
did the obligatory scratch pass. The gage shows it closer to a 7 tpi than 8. Any thought as to what would cause this discrepancy?
This is the first time single pointing with this lathe.