Change gear charts for metric C2 mini-lathe - Imperial and Metric threads

[spuddevans]

Hi folks, last year before I moved house and lost my workshop, I had a little project to do which needed an Imperial thread. This posed a little problem for me as my little Mini-Lathe (Seig C2) was a metric leadscrew, and I was too tight to buy an imperial leadscrew and change gear set just for this one project.

I had read before that it is possible to screwcut an imperial thread on a metric lathe ( or vice-versa ) with many threads being accurate to under 0.5% error, so I set about researching and building a chart. Some of the imperial TPI's have a 1%Err but even with that, unless you are using a really long imperial nut, the error shouldn't create much of a problem.

My heartfelt thanks go out to Marv for his wonderful Change Gear program which did all the math for me, and I made up the attached charts. I made a Metric one as well as the supplied chart that came with the Lathe is far from comprehensive.

So I just thought I would share them with you, just in case there is anyone else out there with a C2 (although I think they will apply to the C3 and C4 too, not sure about the C6)


Tim

[andyf]

Hi Tim,

You could have saved yourself a bit of time with this:
http://littlemachineshop.com/Reference/change_gears.php

Most of the results it gives for inch threads with a 1.5mm leadscrew look pretty close (probably closer than the accuracy of Chinese leadscrews, anyway!). It would be interesting to see how they compare with your chart.

Andy

[spuddevans]

Hi Tim,

You could have saved yourself a bit of time with this:
http://littlemachineshop.com/Reference/change_gears.php

 

Although I didn't have net access in my workshop, so a printed list was more convenient for me.


Thanks for the link though, very useful resource 


Tim