Thread cutting help

[bigphill]

Hi all
I have a 20year old chinese 9x20 lathe. There is no quick change gear box and only limited tpi listings on the label. Its a Toolex brand and I cant find information anywhere on these lathes. Any help on the gearing required would be really appreciated. I'm new to using this machine but looking forward to having a go.
Thanks......Phill

[Jekyll and Hyde]

Suggest you download the program written by one of our members in the thread linked below (most recent version is about halfway down that page IIRC). Should help you out no end!

https://www.woodworkforums.com/f65/la...98/index3.html

[bigphill]

Hi
Thanks for the quick answer. My lathe has more groups of gears than the four list in the calculator. Also may have done the lathe a minor injustice. Its made in Taiwan not China. I know Southbend seem to think they make better lathes there.

[Jekyll and Hyde]

You might be best to take a couple of photos of the gear setup on your machine and post it, in that case... You might find some of the gears have no effect on the final ratio, or can be simplified down to work with the calculator....

[bigphill]

Hi
Hope these help.If not let me know and I'll try some more
ThanksAttachment 214232

Attachment 214233

[Jekyll and Hyde]

I'm struggling to read that diagram for the gears given the size, but I'd be inclined to try expressing the available ratios of W to Z1 as selections in the quick change box section of the program. For example, most of the time it seems from the chart you'd use an 80 tooth gear in Z1, being driven by W (which as far as I can see is always 40?). This would give you a ratio of 0.5 to stick into the quick change section.

Then, I think it should work as normal, with A in the program corresponding to Z1, B and C to Z2, and D to L.

Obviously you'll need to check that the suggested gear for the 'A' position matches to the one required for the suggested "quick change" ratio in picking a valid result out of the program, but I THINK it should work...

[bigphill]

Hi
I'll go and count the teeth on all the gears I've got and try your suggestion and see how i go. Thanks for your help in getting me started.
Phill