Is it posible to make a thread chasing dial?

I'm not totally sure of this,but if you have a meteric lead screw a thread dial won't work. You better ask around about this.
I made one for my SB from plans I got from an article in Popular Science magazine of about 1941 or so vintage.
In order to cut threads on a metric lathe you must keep half nuts engaged and reverse the motor. May not be
true ,but I read or heard it somewhere.
 
I'm not totally sure of this,but if you have a meteric lead screw a thread dial won't work. You better ask around about this.
I made one for my SB from plans I got from an article in Popular Science magazine of about 1941 or so vintage.
In order to cut threads on a metric lathe you must keep half nuts engaged and reverse the motor. May not be
true ,but I read or heard it somewhere.

What is true is that if a lathe has a true imperial leadscrew, then the thread dial cannot be used to cut metric threads. So I just always assumed that true metric lathes with a metric leadscrew would be the opposite, be able to cut some metric screws conventially using the half nut & thread dial but to cut imperial threads they could not be used. I don't know much about cutting metric threads other than the few metric threads I have cut leaving the half nuts engagaed so I don't actually know the truth in this.

I have seen some true metric lathes online with 3mm or 6mm pitch leadscrews & they have thread dials.

PM's version of this lathe has an 8 TPI leadscrew
 
Last edited:
I would guess based on what you have shown that you have a metric leadscrew with 3mm pitch. Hopefully somebody will correct me if I am wrong, but I believe that works out to a module 3 gear. For a 16T gear, the diameter of the blank would be 54mm (Number_of_teeth+2)*module. That's a decent size gear, if you drop down to 8 teeth, you end up with 30mm.

Will has good advice as well, If you have a metric leadscrew, you will only be able to use the threading dial to cut metric threads, for inch threads, you will steel need to reverse with the halfnut engaged. If it is a inch leadscrew, you will only be able to use the threading dial to cut inch threads. Still, probably better than no dial ;)
 
Back
Top