Foolks,
My lathe (Chester Super B) has a 4mm ACME leadscrew but does not come fitted with a leadscrew indicator as standard. I'd like to add one on, ideally by buying a "spare" for this/another lathe with similar leadscrew and starting from there.
Any suggestions for suppliers of the leadscrew indicator ?
Many thanks, Rob Whight
Yes, 4mm Acme, according to the manufacturer.
Ed,
I can understand your question - this is probably what is causing me all the difficulty - nobody else's lathe has a 4mm Acme leadscrew. But (as per Peter's note), I have checked and checked again and am sure I've got it correct !
This must be referring to the pitch of the screw which would be fairly coarse- about the same as a 6 TPI- You should more properly refer to it by diameter and pitch like 19MM X
Even Monarch made a metric-only version of its EE, as did Hardinge of its TL.
4mm is probably the most obvious pitch to select for a metric-only version of an otherwise 8 TPI English machine.Most English-metric machines I am familiary with retain their 8 TPI leadscrews and threading indicators, then add a x/127 transposer internally, but the threading indicator is usable only for English.
I was looking at the thread indicator for my Compact 8 recently, wondering about the possibility of making my own gear in case I stripped it out or something. I expected it to be like a worm wheel, with a concave edge--but it was flat, although the teeth were cut at the lead angle of the thread of course. Wouldn't be too hard to cut a gear with a single-point acme tool, and make your own indicator.
This leads to a stupid question I had--what determines the number of teeth for an indicator gear for any given leadscrew pitch?
My lathe has a 5/8" x 16 tpi screw, with a 32 tooth gear, and 4 marks on the dial.
Would a 4 mm screw also have a 32 tooth wheel, or what?
Ken Grunke
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