Thread: CNC lathes

Is anyone running a manual lathe with CNC controls on the X or X and Y axis ?

I'm thinking of running an Electronic Lead Screw on the X axis to give me infinite screw cutting pitches and feed speeds.
This electronic stuff is well above my pay grade
But It's worth looking into because I know a few guys who are seriously into automation and programming.

I'm just not sure if it would actually work anything like I expect ?

So if I could find someone to talk to or look at how an ELS actually works in use

Or just spend 20k plus on a lathe with vastly more features and thread cutting options

Originally Posted by akaroa1

Is anyone running a manual lathe with CNC controls on the X or X and Y axis ?

I'm thinking of running an Electronic Lead Screw on the X axis to give me infinite screw cutting pitches and feed speeds.
This electronic stuff is well above my pay grade
But It's worth looking into because I know a few guys who are seriously into automation and programming.

I'm just not sure if it would actually work anything like I expect ?

So if I could find someone to talk to or look at how an ELS actually works in use

Or just spend 20k plus on a lathe with vastly more features and thread cutting options

I think its a lot of work if you are only doing one axis, you may as well do both. There is a lot of info online to help you through the steps of retrofitting stepper motors to your manual lathe.

The longitudinal axis on a lathe is Z. Y is up and down, Y moves the tool off center.

Look around for a good quality lathe (Colchester, Harrison, Graziano, Meuser, etc), second-hand but not more than 40 years old, 50mm spindle bore, 1 metre between centres with both metric and imperial threads. Probably in the $6-10K range. They will do everything you want with accuracy and no need to learn the CNC gobbledegook which is a bit of a mystery to us older dinosaurs!. For one-off work the normal lathe is much faster to set-up and use.

Are you planning on doing production runs ? If you are going to make the same part 10,000 times, CNC is awesome. For job-shop type gunsmithing work, not so much.

As far as retrofitting older lathes, speed is your friend. There are some very good reasons why CNC lathes with carbide tooling run at spindle speeds that would make most older manual machines hop around the shop floor if not rip themselves apart...

Personally I have found the perfect combo to be a heavy, rigid machine with a DRO

CNC machines are like testing jigs for electronics, great if you want to do 100's or 1000's of something but useless for the occasional build or repair

Originally Posted by gundoc

Look around for a good quality lathe (Colchester, Harrison, Graziano, Meuser, etc), second-hand but not more than 40 years old, 50mm spindle bore, 1 metre between centres with both metric and imperial threads. Probably in the $6-10K range. They will do everything you want with accuracy and no need to learn the CNC gobbledegook which is a bit of a mystery to us older dinosaurs!. For one-off work the normal lathe is much faster to set-up and use.

I know of a Colchester VS3250 - about 1993 (?) that is on the market be about $12k - digital readout/10hp - 750mm between centres/50mm spindle - - But for the same money that will get you a basic new chinese one - $30k to get a decent lathe the equivalent of the Colchester

Id agree with what others have said. Cncs are great for production runs or complex parts. For one offs of reasonably straight forward parts I wouldn't even look at the cnc.
If you are wanting to thread a rifle barrel then a manual lathe is what you are best to use. We thread 10+ rifles a day here and I wouldn't even consider putting them in the CNC as its just to time consuming setting them up.

Im in the process of making one for my lathe. Im sick of messing around with change gears for threads and I find myself not using power feed at all because its such a hassle to setup.

https://www.youtube.com/watch?v=FTs9GygRQ-U&list=PLDlWKv7KIIr90ZZ7Zqt-ge5nVVdS3WVgg

This guy has developed a diy electronic lead screw and has a series of very detailed videos going into exactly how to build it. He is also now offering kits for the control panel and pcbs at pretty reasonable prices.

Basically its an encoder linked to the spindle, which sends its signal through an arduino board where you select thread pitch or feed rate, and it then drives a servo attached to the leadscrew at the correct ratio.
Not a super simple project and not something that I could come up with on my own, but following the videos and buying the kit he has available should make it fairly straightforward.