Got your pro version right there. 
/edit: Whoops, late to the party… 
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I saw this video the other day. There seems to be some choices between closed loop nema17s that Teaching Tech used and the servos that This Old Tony uses:
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Oh those look too easy!
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These closed loop steppers (with optical encoder) on omc-stepperonline.com advertise having 113.29oz/in (80Ncm) and they are listed for $22.36 each when buying a set of 5 or more, and delivering from stock in the USA. (Cheaper when delivering from overseas, apparently.)
By contrast, the open loop steppers that @vicious1 sells in the store for LowRider are listed as 84oz/in, but priced at only $11.50.
If those closed loop ones need pricey drivers that should also be considered.
Overall price difference sounds “not bad” for a “pro” version machine.
??
What would be the next point of failure when there’s that much torque in the steppers? The belt mounting blocks ?
Possibly. Also, I can see bits breaking.
I used to have the beefier nema 17 (92ozin) -open loop in my old lowrider 2, these motors will rip the belts or the belt blocks first thats for sure.
Good question. In my case, this is on the Z assembly only, with a leadscrew. So ripping up belts or belt blocks is not an issue there. The lead nut may come unmoored, or the coupler may slip. I did ram the collet (no bit installed) down into a piece of wood once since I installed it, by accident. It made quite a dent and I saw deflection of the Z assembly (slight bending of the pipes and the Z core plastic??) before the driver threw a “position error” alarm and shut off the stepper. I suspect one can go into the firmware of the driver and set an over-current protection that would prevent serious damage to the machine.
I have tested out the new closed-loop Z stepper & controller carving terrain and it works fantastically. Here is a video of it carving at 75mm/sec in X, Y and Z, and I even increased it to 100mm/sec near the end of this finishing pass with no problem. The whole finishing pass took under 2 hours, where it would have taken over 6 before.
The stepper motor does not get hot, I would guess less than 30C.
The whole MPCNC current draw (all three axes) is about 1.5A (40V) while it is doing these carvings, even during the roughing pass that is pushing it pretty hard.
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Wow, impressive!
Thanks, and welcome, Briana! Well summarized.
Downsides are the bigger price and size of both stepper and controller, compared to the stock V1 kit.
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