Seig X2 minimill CNC conversion, comments and notes

brought to you by:  Dave Williams
This page: www.bacomatic.org/~dw/tool/x2/comment.htm
Main page: http://www.bacomatic.org/~dw/index.htm
Last Updated: 19 Sep 2008

Author: Dave Williams; dlwilliams=aristotle=net


I had wanted a desktop CNC mill for at least ten years. They had always been out of my price range. But the price of CNC stuff has dropped dramatically, and now there are kits that lower the bar even further.

I had seen the X2 mini-mill around, but the 3.7" Y travel put me off. I finally figured out I could use a rotary table to effectively extend the travel. That made my decision.

The decline of the dollar vs. the yuan had driven the price up 25% or more in the previous few months, but Toolsnow.com still had one on hand at $399 + $125 shipping. That was $525 to my door, $80 cheaper than the next-best machine+shipping on the price grid I built. Toolsnow would only ship to a commercial address and wanted a forklift present. I made arrangements to have it dropped off at a local steelyard. They forklifted it into the back of my station wagon for be, but I unloaded it by hand (gravity is your friend) and manhandled the box into the house by myself. It weighs about 150 pounds crated; heavy, but manageable as long as you watch your back - the box is an awkward shape to get hold of.

I spent a couple of weeks surfing the web, looking at kits and software. I picked the Xylotex stepper kit because it came as a complete assembly in a box; prewired and ready to go. There were others, but they were much more expensive, there were cheaper ones, but they required more knowledge of stepper motors than I could soak up quickly. Lots of surfing found mostly satisfied Xylotex users, though there were a few disgruntled ones. The Xylotex has no overload protection on the output circuits, and disconnecting the push-in connectors while it is turned on will fry the board. I resolved to zip tie the connectors and made the purchase.

The prevailing opinion on the CNC forums was that ballscrews were a necessity if you planned to use the machine much. There were several kits and some DIY plans as of 05/08, but CNCFusion was the only one who offered a complete kit with ballscrews, though others do now. The CNCFusion kit cost way more than the milling machine did, but it was a complete bolt-on kit. I already had a full-size mill and lathe, but I wanted this thing to work sometime in the reasonably near future, not to become Yet Another Project. So I whined a bit and bought the kit.

It took a bit of fiddling to get the CNCFusion stuff to fit. There is apparently quite a bit of variation in the castings on the X2s. I can't fault CNCFusion for that; grinding for clearance was unexpected and tedious, but not difficult.

I wound up substantially modifying the CNCFusion bits later, but they did install and work as promised.

I picked up a used PC on the local Craigslist; I wanted a dedicated machine for the controller. I had planned to run EMC2, which is Linux-based machine control freeware. Unfortunately, EMC2 is based on Ubuntu, which is in turn based on Debian. Of the four machines I had, Ubuntu would not install on any of them... though it did on the Craigslist box. Unfortunately, the diagnostic utility said it was losing stepper pulses while moving. I couldn't fiddle any settings that would fix it, and the web had nothing useful, so I downloaded the Mach3 demo.

Mach3 is Windows-based, and much as I hated having Microsoftware running on one of my machines, Mach3 worked just fine. I could zip the table around all over the place with the arrow keys, anyway. I didn't have the Z axis installed at the time. Later I bought the MeshCAM/Mach3 bundle from GRZ Software.

The next couple of months were spent on upgrades - Y axis extension, limit switches, reworking the Z axis bits, power drawbar, automatic tool changer. I spent more time on my old Gorton mill making parts for the little mill than I had spent on the Gorton over the last couple of years.

During this time, the guys at CNCZone.com were very helpful, sharing comments and pictures of how they did it.

Bear in mind you could just buy the stepper kit and the motor kit, hook them up, and have a useable CNC machine. I went a bit nuts modifying and upgrading mine, but I wanted to do it all once, do it right, and use it without having to keep dinking with it later.


As a side note, when I started this I had visions of writing G-code by hand, like we used to do when I ran a Hardinge CNC lathe in 1983. But nobody does that any more; they go directly from CAD to G-code. And CAD isn't what it used to be, either. I used some CAD programs in the late '80s, what they call 2D CAD now. But "CAD" is dead; now it's all "solid modeling." You go directly from the screen to carving metal; the CAM software - MeshCAM, in this case - does the conversion.
At this time I haven't quite settled on a CAD program, though it looks like I'll buy an older version of the full-house TurboCAD from one of the old- software vendors. I don't mind if the software is three years old when it costs $150 instead of $1500...

So, as of September, I'm still twiddling with the X2 and have yet to carve any metal. But I am having fun now... z