- Joined
- Sep 13, 2018
- Messages
- 8
Hi all , newbie from OZ here . Ive added a Sieg C3 55w mini lathe to my arsenal !. without an integral DRO can any body please tell me the Carriage powered shaft RPM to spindle RPM ratio ? , thanks.
The gear combo for 64 tpi is 20-any gear-80. A 4:1 ratio. The normal gearing on that lathe for turning is 20-80-20-80, as you pointed out. But, that is a 16:1 ratio, equivalent to 256 tpi.Welcome to H-M,
Looks like the C3 uses the Lead Screw as for both Treading and Power Feed..... If I'm reading the manual correctly, (Page 28, 32-33) it is set from the factory with the following gears A=20, B=80, C=20, D=80, which I think is 64 tpi, according to the table, which = ~ 0.0156" per revolution. (Though that seems a bit course ).
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No, that is incorrect IF your change gears are set up for normal turning. With the normal 80-20-80-20 gear setup for turning, the leadscrew turns 1/16 of a rev for each rev of the spindle. So, for a spindle speed of 400 rpm, the leadscrew is turning at 25 rpm. May I ask why are you concerned with leadscrew rpm vs spindle rpm as opposed to carriage movement per rev of the spindle?Thanks for replies , if I got that correct does that mean if the Chuck/Spindle is rotating at 400rpm the Power Feed drive is doing 100rpm ?, cheers