Alright, I'd like to start off thanking everyone that has put up information about their Sx3 or X3. You all know who you are. I've been through ALL of the Sx3 build threads, websites, YouTube videos, all of them. Multiple times. You've all been an enormous source of confidence, information and inspiration.

But I'd like to add in my Sx3 CNC conversion experience now.

First off, I wanted to do this entire CNC project as cheaply as possible at first, then upgrade later. So for now, no ball screws, home or limit switches, spindle control, Z axis counterweight, no bells or whistles.

Secondly, large inspiration to begin the CNC conversion was from the capability to add a 3d printer to the mill, so the 3d printing setup planning was wrapped into the CNC conversion planning.

So firstly the total cost was about 600 USD flat. I'm pretty happy with that.

310 for G540+power supply
200 for 4 stepper motors
30 for 3d printer extruder parts
20 for pulleys and belt
20 for cables and parallel port PCI card

I'm using the G540 with 381oz steppers for the X and Y connected directly, and the new 465 oz 3.5 amp nema 34 connected to the Z with a 1.33 ratio set of Chinese XL style pulleys. I made all the motor mounts from scraps, and I completed the X and Y axis first, so I could CNC the Z bracket instead of manually milling it. I built a 3d printer direct drive extruder and hot end from scraps around a nema23 and bolted it to the side of the head.

Now I know I seen a lot of talk about using ball screws, but I wanted to see for myself how well Mach3's backlash compensation works. I have about .0105 backlash on the X, .0095 on the Y and .0035 on the Z. She seemed to cut pretty good for awhile. Actually shocked me how well everything worked, engraving all sorts of fancy stuff.

But after a few days now, I've noticed some problems.

1. The Y axis backlash amount seems to change .003-.004 randomly every few hours, and even worse, the backlash is different depending on which direction the axis was moving. Is this worth trying to fix? Or should I just go ball screws? (eBay models for 30 bucks with ballnuts?!?!?)

2. The Z worked well at first, max speed of about 30 IPM going up. But it is now giving me trouble if I leave the worn down, most used range of the column, which has limited me to 9 IPM going up. This is due to a lack of a counter weight system or gas spring setup. I do need something badly. But what sort of Z rapids are you all seeing?

3. Did some 3d printing tonight for the first time, and my homemade hot end jams up a lot, needs some work. But I managed to print two layers of an object. I'm using one of the eBay 14 dollar PID temperature controllers to control temperature of the extruder. That's really the only electrical add on for the 3d printing side of things.
Not to mention I did some serious stalling while zig zaging around at 80 IPM. Is 20 inch/sec(?) too much acceleration? Around 60 IPM zig zagging I no longer stall. I can do 100 IPM straight rapids on the X and Y though.

4. And somewhat most annoying, if my speed comes down to 2 IPM or less, the steppers for X and Y will basically stop and go into stand by? Even if I'm running 8 IPM, sometimes a curve calls for a very slightly movement of one axis, and at that point the axis stops? I've setup my minimum speed in MasterCAM to be 3 IPM, but this hasn't solved the problem. Mach3 will still drive the motor below the MasterCAM recommendation. Mach3 doesn't seem to have a minimum speed setting, but is there anything I can do outside of gearing the steppers to solve this?

I'll get some pictures up soon, and again I'd like to thank the entire Sx3 community for all of your contributions. There's wonderful stuff happening on the internet!