Sherline Ultra Sub-Base

When I ran out of Y axis capacity on my Sherline 2000 CNC mill, I bought the extended X and Y axes from A2ZCNC. That was a huge improvement and it's just about perfect but... the larger the work piece that you mount to the mill, the smaller the work envelope that you have along the Y axis due to the position of the column. I never sat down with a ruler to figure out what the maximum work piece could be but I knew I was just at, or perhaps just beyond what I needed to cut the largest gear of the Gary's Clock 2003 that I was making. 

The other thing that I wanted was to add some mass to the mill. One thing that I have learned in building my CNC system is that mass rules - more is better. A friend scored a piece of 1.00" x 12" x 24" steel plate for me which became my new Extra Long, Extra Heavy, Sub-Base. By moving the column back about 3" or so on this big plate, I'll get that extra capacity and the extra mass that I want. Even if you don't have the A2ZCNC extended Y axis, this base should increase the capacity of your stock Sherline 2000 mill.

Since completing this project, I added flood coolant which has worked out extremely well.

Build Details

I decided early on to use aluminum extrusions for my new column. The Sherline 2000 mill arrives with a two-part column so you can adjust the height. I suppose that I could have worked with the OEM columns but mounting it on my new sub-base would have made it way too short. 

It was just simpler to use the 3"x3" 80/20 extrusions. This stuff is very strong and rigid. I ordered 5 pieces and had them cut in 0.500" increments starting a 5.500". The one in the middle - 6.500" is the one that will likely be my main base. I may never use the others.

The holes in the extrusion can be tapped by 80/20 at additional cost. I did it myself. Tap all four holes at one end 5/16"-18

It would have been fairly easy to do things the lazy way and just center the extrusion over the hold down bolt but I wanted it done right and had some method to my madness. I originally designed this plate to be square but I had a piece of scrap just the right size that was round. I just cleaned it up on the lathe a bit. It's about 4" in diameter.

Next I drilled the four 5/16" holes to bolt it down to the new column. The center hole will be drilled 3/8" for the hold down bolt which threads into the new base.

I never swing the mill arm as it was designed to do and I wanted that ability gone - I wanted the arm locked in place. So, I turned a a couple bits of aluminum to fit snugly inside the two bars that make up the Sherline mill's arm, threaded them internally, and bolted them to the plate. These should stop the arm from swinging accidentally.

This is the new base. A friend in the the ornamental metal business grabbed an end cut from one of his suppliers. 

It's 1.00"x11.50"x22.00". At .28359924 Lbs per cubic inch, it should weigh about 72 pounds. And it feels every bit of it.

I ended up having the local waterjet cutter cut it to size and also cut all the holes for me. Cost - $125 Cdn. The holes are clean and accurate enough to tap.

I did a little cosmetic sanding and sprayed a blue hammer finish on it.

The two holes near the top of the picture are for bolting down the A2ZCNC extended base. They'll be tapped for #12-24 machine screws.

The center cluster of holes includes a 3/8" center hole for the hold down bolt - same as the stock Sherline. The four corner holes around the center are tapped 5/16". The first stud is screwed in place. When all four are screwed in, the 80/20 extrusion fits nicely over them. The studs stop the 80/20 from turning. The extra two holes are to accommodate the stock Sherline column if I ever find a need to mount it.

In the far corners are small holes ( only one visible) to screw the base down to the bench.

All four studs mounted under the 80/20 extrusion and the new column temporarily in place.

The next job is to tap the #12-24 holes to hold down the A2ZCNC base.

All of the holes lined up perfectly and the A2ZCNC base fits perfectly onto the new steel sub-base.

The next step is to find a bit of 3/8" stainless threaded rod to mount the arm and 80/20 column.

A couple more photo's of the finished (for now) mill.


Updated August 04, 2014