Hi
I spent a relaxing afternoon yesterday making a wash out plug for the boiler
It was a good opportunity to practice some screw cutting 1 1/2 inch BSP
a nice meaty thread.
As my lathe has no gearbox i set up a compound gear train to cut 11 TPI
The job went well no broken tools ,when i got near finished size i removed the chuck from the lathe to test fit the plug.
It would start but was tight i checked the thread pitch to my horror it was wrong ,i checked the change wheels all seemed good .I had previously screw cut the thread in the boss the plug was to fit
I looked again at the gear chart the last gear was 24 tooth a small black mark had changed the 21 in to a 24 on the chart .at least i found the problem ,
Now to start again