CNC Mill Conversion with Pics and Video. (DONE!)

Hi All! I haven't been on BLF much lately. I've been busy with some other projects, including changing my mill over to CNC (and designing a flashlight). I have always planned to convert my mill, but was recently offered the bulk of the equipment needed at a price I couldn't refuse. So , I dropped everything else and started making parts for the changeover. I have quite a few hours into the conversion already but am not nearly done yet. I'm tired of being in the basement today, so I figured some of you might like some pics and maybe a video or two.

Here are a couple of pictures of the pulley drive conversion that I did (changing it over from el cheapo plastic gear drive).

The motor mount plate pivots on the left. The copper colored washer is a belleville(spring) washer.

There is a slot on the other side for belt tension adjustment.

Stepper motors: :)

Breakout board that interfaces the computer and the motor controllers. Wiring this pig will be a chore!

Motor Mounts that I made. Believe it or not, but making these along with the standoffs and the ballnut mounts saved me over $700.00.

Motors mounted. The piece on the right is a spacer that accepts two bearings.

Here is a short video showing the before and after the pulley drive conversion.

I have some more videos you can watch on my page if you are interested.

By the way, anyone know who's this is? Hint Hint.

Wow, what a difference.


That mill is a SEVERE INJURY HAZARD. Send it to me (after you have it converted) and I will dispose of it properly.

Lovely. I hope you plan to make flashlights on it.

I do :) In fact, after I get it up and running to my satisfaction I am going to add a 4th axis. That will allow me to do some really cool things.

You will have much fun with your CNC :party:

Do you intend to use ballscrews ?

James, I will be using ballscrews. They are the last major expenditure. I'm waiting a bit so the wife doesn't squawk too much :)

Just for reference here are links to what I have so far and what I'll be getting.

I have this. Not shown, but included in the deal were the lovejoy couplings and enough 4 conductor twisted pair to do several machines.

I made the equivalent of this, saving myself about $700.00. They are the mounts for the stepper motors and the ball screws.

I have to buy these ball screws to complete the build.

I may buy this to controller box to house all of the electronics instead of making my own out of a retired computer case since it won't save me all that much money and will save a lot of time. It comes with the switches and all of the necessary connectors, which add up when buying them separately.

Fritz you may know this, but the 4th axis allows me to rotate the part while it is being machined in the X-Y-Z space. I'll be able to engrave or machine any design I want on the curved surface of a light. Wacked out knurling, wording or even line art is possible in addition to practical operations.

Very very nice work!

lovely stuff! Did you keep the same speed range or bump up the top end with the pulleys you made? I've heard that as one of the main reasons for going belt drive, aside from the lower noise and not stripping out gears in a crash. The G0704 really is a good size for a small hobby mill, I'd love to have one.

What software are you going to use? Any idea on the rotary table?

Matt, it will run just over 4k RPM on the high speed pulleys as is...quite a bit faster. I will eventually upgrade the spindle bearings so I can go higher, but will also need a larger motor eventually. I will do the spindle bearings and the new motor (and controller) at the same time. I've looked at the motor thing quite a bit and may go with a 3 phase motor and VFD so that software can control spindle speed.

I will start out using Mach 3 for software, though I'm really interested in Linux CNC. We'll see how Mach 3 goes. I want to get everything up and running, including the 4th axis before I switch over, if ever.

I'll initially probably start out with this for the 4th axis. It's pretty small, but at $300.00 it is a good place to start.

I will eventually make my own that is more robust using a NEMA 34 stepper motor and a harmonic drive reduction gear. Rotary tables are ok for 4th axis, but their backlash (gear slop) is pretty large. That makes them tough to use for CNC. It is possible to adjust the backlash out, but it quickly comes back due to wear. They just aren't designed to be adjusted that tight for long.

Might as well give an update while I'm here.

I machined the Z and Y ballnut mounts. I had to do the Y mount twice. I read the wrong dimension when milling one part of it to thickness. I'm waiting to do the X ballnut mount until the ball screws get here. I ordered them yesterday. Hopefully, I don't have to buy much more for this. The wife is pissed.

I took some pictures along the way. I'll try to get them posted.

No, the machines I used long ago didn’t have such a thing, just simple lathes and mills. Why do I see a total of only four motors for four axes? Is there a tool drive motor not shown?

The $300 for the 4th axis is really not that bad.

On my flatbed I use Mach3. I am not sold on v.4 yet and v3 is very proven.

Not sure if this helps but on my gear reduction units, I use the 3/8" kevlar timing belts and they are tight as hell (for the last 4 years). Considering the gantry alone weighs approx 400lbs I can definitely say I have confidence in the belts. When my friend was building the belt drives he had called SDP and actually spoke to the engineers about the application and came up with that particular belt.

If you do not have their web address it is:

Fritz are you referring to the spindle motor? It's in the top pic.

bugsy, that price is pretty good for 4th axis but it is pretty small at 3 inchs. Mag heads will probably be the largest thing it will hold without a mandrel. It will be something to start with though and the price is right. I can't build one at that price so it will have to do for a while.

If memory serves....don't they make jaw adapters?

The Taig and Sherline rotary tables are 4”.

Also this one is supposed to be decent:

bugsy, they probably do. I would probably make jigs to hold larger work anyway though.

pyro, thanks for that link. I roughly figure it's OD capacity is roughly 1/2 of chuck size, thus my Maglite head statement above.