[zRob]

Hi guys,

Is the gShield still an option? or the TinyG? I have a manual Taig mill with the small std motor its about 12 years old now. Looking to convert it to a 3 axis CNC just as a learning project I have no plans other than maybe trying to mill a PCB or machine some small aluminum or brass parts just for fun.

Thanks for any advice.

[awerby]

I'd suggest getting the motor mounts and couplers from Taig; they're reasonably priced and make the conversion a lot easier, if you're using NEMA 23 steppers with 1/4" shafts.

[zRob]

Hi, Thanks for the reply. Yes I did order the coupler kit from Taig did not arrive yet. I was curious about shaft diameter though, is 1/4" my only option with these couplers?

[awerby]

I suppose you could bore them out if your motor shafts were larger than that. Or use bushings if they're too small. What kind of motors are you planning to use? If they're NEMA 17, that's too small.

[zRob]

Yes NEMA 23 and possibly just experimenting with Arduino and some free or open source G-code editors, but this is all new for me so not sure how far I will get. I am also re-considering my driver motor controller, and now looking at the $20 rage per driver like 3.5A-4.2A range stuff you would see on Amazon like a DM542T, TB6560, or something similar because the driver boards I mentioned in my first post may not be suited for NEMA 23's I am thinking.

[awerby]

The TB6560 drivers have a terrible reputation, as you can find out by searching this forum. The TinyG and Arduino systems are marginal for 23-frame motors. The open-source G-code interpreter/controller software that gets the most respect is LinuxCNC.

[zRob]

Good to know thanks for those comments. One question about closed loop steppers, do you know how difficult that setup would be to a stepper without that? I guess my thought is I am doing non critical parts and I have no need for time constraints so I plan on running it slow. So is it worth it in my situation?

[awerby]

Closed-loop steppers are a sort of hybrid between steppers and servos. They don't really behave like servos, which, if they fall behind their commanded position will exert extra effort to catch up. Instead, they will keep track of any discrepancy between the postion they've been commanded to reach and where they've actually reached, and if it's too far out, they'll stop with an error. This can be a good thing, since it can save your part when the steppers lose steps, but that shouldn't happen in a well-tuned open-loop stepper system. They're certainly not required, and they're considerably more expensive and complex than a regular open-loop stepper system.

[zRob]

OK good to know, I'll be getting three open loop steppers. I been wanting to set this up for years now and I think its going to happen within the next few months. I'll keep you posted, and I think motors will be next then controllers, or as each paycheck comes in I'll be getting stuff.