Studio of Bill Ooms

Bill Ooms

Building A Computerized Ornamental Lathe

The XZ Stage

My Present Stage

The XZ stage is the most critical (and most expensive) part of the hardware. If you scrounge on eBay, you can often find an appropriate stage. However, be prepared to overhaul the stage -- there is a reason why the prices are cheap on eBay! Another source for used stages is Powell's Surplus.

The stage must be extremely rigid and repeatable. Absolute accuracy is less important, but will usually accompany a stage with good repeatability.

When talking to manufacturers (or looking for used ones on eBay) you will see people referring to these as an "XY stage". That's the orientation of the axes for a milling machine and many other applications where Z means the up/down direction. Don't get confused. I'll continue to refer to it as an XZ stage because that's how we will use it on the lathe.

My stage is a Parker Motion Series 300AT stage that I bought on eBay for $150. The grease on the lead screws was like old chewing gum. That was a great deal and I've never seen another like it for anywhere near that price. New price on this unit is about $6500. You can download the data sheet and look at the detailed specs for a "standard grade" #310062AT.

There are many other stages that would also be good. Here are some important things to look for in a stage:

The one thing I really dislike about my stage is that the linear bearings are open to collect wood dust. I've had my wife sew up a spandex "skirt" to attach around the stage and attach it with velcro.

A Better Choice?

If I had to make another stage, I would look for a Parker 404XR series. The wonderful thing about these stages is that they have protective dust covers, and they have a positive pressure port so that you can run a low pressure air line to it and keep the dust completely out of the insides. Also, the repeatability is a extremely good at +-3 microns! The 4" width should give adequate rigidity. I'm starting to see some of these show up on eBay for reasonable prices. New price is about $1900 per stage (multiply by 2).

If I bought new ones, I would get part number 404150XRMD2H1L12C3M3E1B1R1P2 and P3. The P2 and P3 means that the two stages are pinned together perpendicular to within 30 arc-sec.