Well the lathe has been sitting in the garage for long enough and now it is time to dive into the conversion. My goals for this project are to produce a precision tool that can be both used for CNC use and manually via MPG handwheels for one-off and quick jobs.
This isn't a budget build but for around the same price of a nice used HLV-H that turns within tolerance (between $6500 and $10,000), I hope to get essentially a like new CNC lathe. The specs will be as follows:
1) Automation direct drive 400w AC servo on X
2) Automation direct drive 750w AC servo on Z
3) Mach4 with GRex
4) New 2hp baldor vector duty motor and 3hp vector drive (more on this later)
5) Ground ballscrews: X off eBay, Z probably purchased new
6) Super precision ballscrew bearings (both off eBay for $55 each)
This project is just as much a restoration as it is a conversion so will take a while to complete. The first step was to strip everything off the lathe so I can get the bed reground and refit the saddle and cross slide. Then I plan on scraping off the very poor brushed paint job, filling any bad scratches, rubbing down and spraying with a two pack grey enamel.
Below you can see the stripped down lathe. For the X Axis I picked up a very nice ground NSK ballscrew off eBay for about $220 (I actually got two). This is 16mm with 5mm lead and has never been used. The tricky part of this conversion is how to drive the X Axis. There just isn't enough room in the saddle casting to mount the ball-nut in the usual place. So after reading a couple of posts here on CNCZone I decided to extend the saddle at the back and fit the ball screw nut to the back of the cross slide.
Below is my initial mock up design for the X-Axis. I'll add more detail tomorrow.
With the cross slide covers hidden: