Question about leadscrews on a Bolton 1337g

Uguessedit

Active Member
Registered
Joined
Mar 7, 2018
Messages
40
This is probably expected for a Chinese machine but I’m asking so I don’t make a mistake. I’ve been trying to get replacement parts for my bt1337g for months now and it’s become apparent it’s not happening. These small boutique sellers just don’t have the support like Grizzly. I need to make my own lead nuts and have a nice bar of bronze here. I’m pretty certain the saddle has a m14 x 2.5 pitch left hand screw. The tailstock is questionable. It’s left hand but the size is more like 13.7mm and the pitch looks like 10tpi. That’s bigger than 1/2 and smaller than 5/8. Nobody makes 9/16 that I’m aware of. The compound is also smaller 13.7 and right hand thread and that one seems to be a 2.5 pitch though a 10tpi gauge also fits nicely in the teeth. This is throwing me off. Obviously either has 10 teeth per inch. I’m going to think that they are all 14mm x 2.5 pitch left and right hand unless someone has some wisdom that may suggest otherwise. Photos attached and in no particular order. I’m tired of the slop so maybe the screws wore down I don’t know I can buy pre cut stock in 36” length and cut off what I need and turn down and thread the ends. My other option is to spend more money and buy a handful of grizzly parts and see what may fit.
 

Attachments

Cadillac

Bronze
Registered
Joined
Mar 12, 2018
Messages
1,144
I would look into them being american thread size. I have a optimum 14x40 lathe and it says the leadscrew size and pitch in the parts manual and all three are imperial. I don’t think you can use a standard thread pitch gauge for a acme thread not the same. When I get home I’ll confirm my sizes but they are imperial.
 

markba633csi

Platinum
Registered
Joined
Apr 30, 2015
Messages
4,306
How much slop (backlash) are you getting? All lathes have it, some more than others
 

Glenn Brooks

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Nov 14, 2014
Messages
788
If you are interested in having a lead screw and nut made for you, you could contact Bob Miller at Miller Fabricating and Machine. He made up one or two lead screws for my 14” south bend lathe. He delivered really high quality work, at a very reasonable price. Cleared up all my precision problems on the lathe.

Here is his email. Sorry don’t have his phone number, for some reason.

millermachineandfabrication@gmail.com

Glenn Brooks
 
Top