Cnc mill a possibility?

I noticed that along with the seig X1, next to it on the floor is a clarke CMD10, I am pretty sure they are very similar machines (or in fact the same machine in different branding.)

not sure if i should have added this to the cnc router discussion

Anyway… has anyone looked into the possibility of adding stepper motors and turning one of these into a cnc mill?

i was looking at getting a proxxon mf70 myself to do this to.

just a thought

Both mills are on loan. The Sieg belongs to jonathonjo (Discourse username). The Clarke is Joe’s. There is an intention I think to convert Joe’s mill to CNC.

Short answer is yes !

I will get back on this when I have enough time but it it quite high on my project list.

As an interim, digital readout would be a nice modification. You can do it with digital calipers. Especially useful for doing things in mm rather than thous.

Digital calipers are exactly what @frasco was suggesting

I had a look at this, it actually looks trickier to install than the cnc mod and there are quite a few drawbacks to using the caliper type ones. Would be really, really useful though. The readouts are also immune to the mill’s backlash, unlike a basic cnc mod.

After talking to @joeatkin2, I’ve changed my mind. Don’t think the response time of digital calipers is good enougth for cnc.

But fitting digital calipers for manual use is a different matter!

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they also tend to switch themselves off and reset the zero apparently

Usually the problem is exactly the opposite.

Many don’t switch off even with the ON/OFF button.

The battery drain thing?

Indeed!

I always remove the battery between uses

Can’t we just put on some rotary encoders with a digital display, super simple electronics project?

The reason with going for linear encoders is you take into account the significant backlash on the lead screws

So basically there is no point in doing a CNC project on low quality mills like these?

They all have some degree of backlash. I don’t know how much of a problem it is for cnc yet as:

a) there is an anti backlash nut on each screw, but it makes turning the knobs much stiffer which is why I haven’t bothered dealing with it yet. May just mean we need slightly bigger motors or fine tune the mill’s adjustements to find a sweet spot. I certainly wouldn’t rule out trying the conversion though. Will be much better than the shapeoko.
b) not sure about this but possibly the backlash could be measured and taken into account with the right software ?

I see

I thought that was part of the beauty of using vernier calipers: we know exactly where everything is.

I’d have thought the backlash could be measured and taken into account in software as you suggest.

here is a seig x1 cnc in action, (with belt drive from the steppers rather than direct)

yes exactly, the calipers go onto the sides of the t-slot plates, which means the measurement is made with backlash included so you don’t have to worry about it, you know the measurement is correct

if you’re using rotary encoders you’re going to be putting them on the lead screw, so before any backlash occurs, and it won’t be taken into account in the measurement

Wow that is working really well. Those look like nema 23 motors I think ? The ratio on the belt gears doesn’t look huge so I’m not sure what the benefit is. I was thinking of using a direct coupling.

Why on earth is the spindle making that awful noise though ?