A2ZCNC's Long Travel Table for the Sherline Mill

A2ZCNC makes a Long Travel Table for the Sherline Mill. Having run into travel limitations with a bunch of the projects that I've done, I decided that this would an excellent addition to my mill. The table can be purchased with or without 10-32 tapped holes. I chose to go for the version with the tapped holes. There are 3 rows of 16 tapped holes.

The dimensions of the Sherline table is approx 13" x 2.75" x 0.88". The A2ZCNC table measures 19" x 3" x 1". My first thought when I discovered that the table was thicker was to see if the CNC rotary table stepper motor would clear the Y axis stepper motor. Unfortunately, it still doesn't quite clear without a sub-plate of some type.

Test for flatness

The first thing I did was to check the table out for flatness. I have a 12 x 18 x 3 granite surface plate that I purchased from Busy Bee Tools. I put the table on the surface plate. The table "sounds flat". This is hard to describe, but when you place an object on a surface plate, flat objects (or close to flat objects) make a sound which is different from objects which aren't flat. I then put my Veritas 24" steel straight edge (which is accurate to within 0.001" over its lenght) on the table and shone a bright light behind it. I've been told that the eye is capable of detecting light through cracks as small as 0.0001" (one ten thousandth of an inch). I was unable to detect any light between the straight edge and the table. If I positioned the straight edge over the holes, then a small sliver of light could be seen just on either side of the holes, which is probably caused by the tapping operations.

I also noticed that while the anodized finish is smooth, it wasn't quite as smooth as the original table. Tim Goldstein (from A2ZCNC) thought that this was due to the combination of cast aluminum being anodized. Tim said that 6061 from the same anodizing batch was as smooth as the original table. Bigger...

Tapped Holes

I was pleasantly suprised to discover that the holes on the table had the same spacing (1.16") as those found on the Sherline's Mill Tooling Plate (A2ZCNC also makes a equivalent tooling plate). I've made a few sub-plates, like the one pictured here, for times when I need to machine all the way through a piece. Bigger...

First Use

As luck would have it, the very first project that I had to do after installing the long table was to flycut a 7.5" piece of aluminum. Using the fly cutter and clearing the material on each side requries approx 2.5" of extra travel. This means I would have needed 10" of travel, which isn't possible with the Sherline table, but fits well within the A2ZCNC table quite nicely.

If you look closely, you'll notice that I filled all of the tapped holes with set screws (to keep the swarf out). I suggested to Tim that he provide set screws with the tapped version of the table, and Tim indicated to me that future orders will include the set screws. Bigger...

Tim told me that there seems to be some variation in the dovetails on different mills. I found that I had to loosen off the gib a tiny amount to allow the new table to fit. Before installing the leadscrew, I ran the table back and forth through the extremes of travel to see how it felt. Extra pressure was required at the extreme ends of travel, and this is caused by the weight of the table hanging off one side. If I lifted slightly on the end of the overhaning end, then it was just as easy to move as when in the middle. This means that you may need to slow down your X rapids if using CNC. I currently have my mill setup to rapid at 10 IPM (using Mach2) and I can rapid through the entire 14" of travel with only a minor change in the sound of the steppers as they approach the extremes.

The table came with a small clip which installs at the far left side and keeps the leadscrew from wandering about. As I was screwing the leadscrew into place (using the jog function of course) I noticed that the leadscrew would occaisonally whack into the bottom of the table, so the clip was a nice touch. Also not visble in the photos, there is a tapped hole at each end on the bottom of the table where a "stop screw" can be installed. This is the same as is found on the Sherline table.

All in all, I'm very impressed with the new table, and it will be a permanent fixture on my mill. I like having the additional setup room and that extra little bit of travel comes in handy.

Pete Brown got one of these shortly before I did. His experiences with the table are documented over here.

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Copyright 2006 by Dave Hylands