Well there you go, the setting for C2 has a 100/120 compound in the train. I said the driven works out to 72, well 72/120 x 100 = 60
Something doesn't agree because I make it 21/72 from the above.
Where does the manual come from?
run that past me slowly plz
Look at the picture of the gear setup it shows a 21 driving a 120 which is joined to a 100, which is driving the 60. The 120/100 compound gear gives a 6/5 reduction.
Check out the 22tpi setting in the chart above that one. It uses setting A, 2 and gears 35 and 30. Run the formula for that setting and you'll find it's correct, because it has a idler gear not a compound.
also before I posted the photo of the colchester plack, you came up with the 21/72 combo.
how did you work that out plz
For the metric threads you do exactly the same thing but with the metric formula and you need the 120/127 gear in the train
and what way round does this go????
so is the 120 meshing with the driver or the 127 ?????
I have a strange feeling you are going to say it does not matter lol
I now have had time to take note of my bantam gears that come with my lathe plus a recent flea bay score for a job lot of bantam gears
I always had, the 100 to 120 and sitting under may lathe (in its holder) I have/had the 127
with these came 21/30/35/49/55/57/60 x 2 (two 60t gears came with the lathe, one fitted and the other a spare)
My fleabay score was 21/36/39/42/49/55/57/60/59
so I now have 2x21T/30T/35T/36T/39T/42T/2x49T/2x55T/2x57T/3x60T/69T plus the compounded gears as said 100/120/127
I wish to be able to cut a Metric thread of 5mm and latter a 1.5mm for a ER chuck
In your photo it shows exactly how to set up for your metric threads. For 5mm your 35 tooth stud gear x is driving the 127 which is compounded to the 120 which drives the 36 tooth gearbox input, and the gearbox levers are set to C5.