ML7 : To convert, or not...

[Doddy]

I actually made a 64 slot disc with slot opto sensors. https://photos.app.goo.gl/66KmdtD7TzUziNih7 you have to be able to move the sensors around to get the correct sync

edit: if I was to do it again I might have used a rotary encoder (it would have to be low count with a PP) But its been working for at least 3 - 4 years

https://photos.app.goo.gl/JH1GWVQbhxe6Z6Yo7 This is it simulating an arc that I needed to put on a roller for my belt sander

Clive, if you don't mind I'll cross-reply here to avoid stealing too much(!) of th thin-client thread. This is likely to become something of a conversion thread.

Cheers for the photos - very interesting and useful. I do, and don't like your approach on the saddle - it's a nice design but for my purpose I think it protrudes somewhat into the user space (I've a 13' by 7' shed so have to tip-toe between benches and lathe). But I agree with the two MPGs (I've got one knocking about somewhere) - think that's a necessary solution to keeping a semi-manual mode on the lathe.

The spindle encoder?, I know mach3 needed 1ppr, heard that linuxcnc can use more, effectively. Your experience is that 64ppr is a good number?, it's as good a number as any I support. The quadrature encoding is usually easy enough - easier if you can get a twin-sensor coupler with a pitch smaller than the hole gap space, if you're not worried about symmetry on the A/B signals. That side of things doesn't worry me but good to see that you took the same approach as I'm thinking for the spindle mount.

This, just a placeholder for me to ask more daft questions as I move through the build.

[Clive S]

Not sure what you mean by this

easier if you can get a twin-sensor coupler with a pitch smaller than the hole gap space

re the 64 pp rev you you want it for threading then you won't be running the spindle fast. I think I have tested it at about 600 rpm. 64 was just the number I drew the disc in cad. you could also just use one sensor on the disc and another on a tooth some where as long as it is 1:1 with the spindle.

When I change the motor I might have a go at CSS (constant surface speed) with a VFD for the fun of it.

With the 3 sensors like mine it could do rigid tapping. Although I have never done it on the lathe.

Edit re the mpg's I used the same mpg's between the mill and the lathe with the same control box with 5 drives in it and one mesa card (using only one machine at a time)

[Doddy]

Not sure what you mean by this

Something like the TCUT1800X01,



This has 4 detectors at differing X/Y positions capable of quadrature encoding with index pulse.

Now that I've bought 10 of the little darlings I think I might need to upgrade my soldering iron. Or microscope. Or both.