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I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.
There are several metric pitches that can get pretty darn close with standard English overlaps.
Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.
I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2
Compare that to the change gear lathes I think you would see that the QC is hardly "extremely limited"
Hope I'm making that clear.
On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:
>>In addition, you can cut Metric threads very, very closely with but one gear change
Please explain further....Thanks
On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote: