Converting a Warco Mill to CNC

[Robin Hewitt]

I did the Warco Major. I think your plan to convert it using the existing screws is exactly the right way to go, that is what I did, but you will need a screw to drive the quill if your motor doesn't have the legs to lift the bed.
Once you have a working cnc mill you can decide if you want to make it better.
A man has to ask himself, how much backlash is too much?

[thorphar]

Just on the first stages of design. This is the first version for the x-axis cnc mounting. I am looking at using 48 tooth 9mm HTD5 and 16 tooth 9mm HTD5 pulleys. Next drawings will be for the y-axis. Im saving the z-axis till last as I think it will take me a very long time.

I forgot to add the slots on the stepper mounting to allow for belt tensioning.

[i2i]

have you thought about driving the base of the z axis screw rather than the right angled motion shaft. More direct than either method you described.

[thorphar]

have you thought about driving the base of the z axis screw rather than the right angled motion shaft. More direct than either method you described.

Good thought.

I did have a thought about direct driving the x and y with a stepper. However, after looking at other conversions it seems that everyone has done belt systems rather than direct drive, and only direct drive on smaller machines. All that I could think of for being an advantage would be that you would increase the available torque. Im not sure how much torque is required however im sure that a single Nema 23 3Nm stepper would be suitable for operating the axis'.


If anyone has any some thoughts on this, again any suggestions would be sooo helpful.

[i2i]

Not exactly what i meant. What i was suggesting is to drive the actual Z screw in the knee with a stepper "through a belt reduction if you require", but not through the angle drive present on the front of the knee.

[thorphar]

Not exactly what i meant. What i was suggesting is to drive the actual Z screw in the knee with a stepper "through a belt reduction if you require", but not through the angle drive present on the front of the knee.

I was interested in what axis' would require a belt system in order to reduce cost. I did some tests on the handwheels using a newton gauge and a lever. Here are the results I got.

Axis	NM
X	1.68
Y	1.41
Z-Via Knee	8.0

I also wobbled the handles and measured how much slack there was in the screw.

Axis	Slack
X	0.85mm
Y	0.06mm
Z - Via Knee	0.08mm

Im gonna do some more testing but it seems i could get away with out the belt system on the x and y and just direct drive with a 3Nm Nema 23 and use a belt system on the Z.

[thorphar]

In light of this recent discovery. I have re done my basket.

I use to use AM882 however, after looking around online someone mentioned the DQ860MA Driver being ok instead of the AM882. Im just worried about the lack of sensor less stall detection not being on the DQ860MA. Thoughts ?

Apart from the drivers im pretty sure on the rest, however if anyone see a major mistake, please let me know.

For the Z-Axis driven through the knee

2m2280N High voltage driver
Nema 34 - Sy85STH156-6204B 12.1Nm
suitible coupler to go between the Nema 34 and the z-axis rod.

For the x and y axis

Nema 23 3Nm
DQ860MA
Custom Power Supply
Coupler to go between Nema 23 and Axis drive.


I use to use flexible couplers, however in this kind of situation i believe a solid coupler would be appropriate. I don't know of any good suppliers for solid couplers however Im pretty sure I can make them.

[Robin Hewitt]

There are 2 kinds of toothed pulleys, timing belt and power transmission. I use XL pulleys because I have been caught out by backlash the one time I strayed. I am not saying HTD5 is wrong, but have you checked?