Thread: 7x12 Mini Lathe Conversion

Hi Marty,
Thanks for making the effort to post - the pressure is on now you have posted.
I will follow this with interest to see how it comes along.
Are you going all out and making a console?

Pressure is good Rod this way I can come in here for abuse motivation to get it finished

Hadn't thought about a console to be honest, but once I get familiar with Mach 3 that may be the way to go. I have thought a lot about setting up a couple of MPGs though.

To fit the kit all that needed is to drill and tap a few holes.

I started with the X Axis on the saddle.

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Some interesting clamping methods were adopted Transfer punches came in handy here.

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Although the kit arrives assembled you will disassemble and assemble it many times during the fitting process.

Once that was all aligned and fitted I moved onto the Z axis. I checked a few times for any binding or misalignment along the axis. I initially fit the Z using two bolts and then drilled the two remaining afterwards.

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I used a 1/4" transfer punch clamped to the coupling to help drive the Z axis ballscrew which made it a lot easier.

The lathe stripped of the leadscrew and associated gears. It's interesting as the lathe gets more complicated electronically it seems to get simpler mechanically.


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The two axes fitted.

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Next up will be the Stepper motors.

Hi Marty,
Coming along nicely there. Neat way of mounting the screws on the far side of the lathe. I assume you don't need to refit the apron to the lathe.

Hi Rod,

there is no need to replace the apron with this kit. Got some of the electronics started but will have to wait till next week for an update

I've got a little bit of the electronics done although it's school holidays so not as much as I would have liked.

I used some 4pin connectors, which I shortened slightly on the stepper motor wires. I think they should be able to handle the current.

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I used shielded 4 core cable from Jaycar and went to Homann Designs GC-02 breakout boards for the G540.

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The stepper motors feature covers made by DY Engineering. Both my 155oz and 269oz motors have a current draw of 2.8 amps so both potentiometers were set to 2.8Kohms.

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Note: On the data sheet and screen printing for the GC-02 boards, the stepper motor pairs are referred to as A/ and A instead of A+ and A- and the same for the other pair. I'm not sure why that is.
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My wiring legend (Feel free to point out any mistakes!)

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Next up will be the actual controller. I'm considering using an old laptop I have here. I know traditionally you're not supposed to use a laptop but I've read mixed reports if you are using a smoothstepper. Anyone have any thoughts/experiences?

Hi Marty,

Wiring looks correct. The A and /A, B and /B are used to differentiate the two coils labelled A and B. For each coil the A and /A, B and /B differentiate the two wires within each coil.

There are no right wrong way to do it. Some do use +A and -A, but the + and - in this case are also used just to differentiate the two wires in the coil. A coil is does not have polarity, and in electronics the + and - symbols are used to indicate polarity which does not apply here so I don't use it just to differentiate the two ends of a coil.

Thinking about it, it may have been better to label them A and a, B and b.

The main point in wiring up the steppers to to wire all motors the same so that they are interchangeable.

Cheers,

Peter

Thanks Peter for providing some clarification. How is your mill build going?

Hi Marty,

It's going a bit slow at the moment. There just doesn't seem enough time at the moment. I'm tring to get the Z-Axis done at the moment.

Cheers,

Peter

I hear you Peter I still have the X3 to go after this

Anyway this is what I got started on today.

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The tray cost a small fortune to get made, but I'm grateful they even did the job.

More updates in a week.