WM180/DB7 mini lathe to cut 32TPI

Many thanks Neil. I don't know how you guys work it out!

Many thanks

Ian

Lainchy,

It has taken me a while to figure out the gearing drawing shown on the plate for your lathe, but the working elements are 30/75 which is 0.4. Multiply that by the leadscrew pitch of 2 mm and you get the threading pitch value of 0.8 mm which might be close enough for your purposes. The Far Eastern lathes do not make it as clear as they should in my view, which gears are used as idlers and even in some cases just acting as spacing collars, very confusing.

The top end gears shown on that plate are an idler of 80T linking the fixed spindle gear of 40T to another of 40T for a neutral drive up at that point. That 40T is coupled to the 30T that does the business

Neil has taken the calculations further forward to get as close as he has to 32 tpi and he has also gone to the trouble of working out the clearances needed to get the necessary daylight between all the gears

Regards Brian

Personally I cheat for screwcutting.

I go to the LittleMachineShop website, "Learning Centre", "How to Articles", then "Change Gears for Threading" as my starting point. It is for a Mini-Lathe with only a 2 train gear set, not the 3 train that you need for your lathe. But in conjunction with your threading table, it gives a good idea what you need. I'm afraid it does not do it all for you, you still have to fiddle with the gear sets to get a good arrangement.

Some Imperial TPI could probably do with having additional gears to those that you have, something for another day perhaps.

I hope it all works out.

Neil

Talk about doing things the hard way! I always use ME taps and dies for making my steam fittings. I have NEVER had any come loose or heard of anyone else having that problem!

Andrew.

I go to the LittleMachineShop website, "Learning Centre", "How to Articles", then "Change Gears for Threading" as my starting point. It is for a Mini-Lathe with only a 2 train gear set, not the 3 train that you need for your lathe. But in conjunction with your threading table, it gives a good idea what you need. I'm afraid it does not do it all for you, you still have to fiddle with the gear sets to get a good arrangement.

Some Imperial TPI could probably do with having additional gears to those that you have, something for another day perhaps.

I hope it all works out.

Neil

Cheers Neil. I'm still learning - 18 months in maybe, so this is helpful

If you could find, or make a compatible 21T gear, you could double up the 16 tpi set up,using it to to replace the 42T on C..

Or a 48T in place of the 60 on A in the 40 tpi set up.

Either might open up all sorts of new pitches for you

Howard