Where can I get pro stepper motors

I don’t have the budget to buy a Pro so I am designing my own upgrade to linear rails for my standard SO3 using HGR15 rails mounted to the stock Y rails and a 80 x 120mm extrusion for the X rail with side plates similar to the pro and I need to source 3 nema 24 steppers with the longer shafts and 15mm pulleys.

Does anyone know where I can buy them?

They look to have theirs custom made to get the connectors and wire lengths they want. Also, the Pro motors have different connectors. There are plenty of motors available with pig tails with the proper degree steps and amperage which I think are labled on the motors.

I would solder new connectors on if I had to. I guess I’ll email sales to see if they will sell me a set with pulleys and 15mm belts with the clips for a mark up. That way I get what I need and they still make money on a sale. I have way too much into my SO3 to sell it and buy a pro and this way I know the motors are a 100% match.

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They sent me a Pro and I still value my Original XXL to not sell it. Why get rid of such a good companion?


I wouldn’t sell it as I have to much money invested on upgrades like HDZ, 65mm HD mount, Bitzero, Bitsetter, SMW aluminum bed, that’s why I’m making custom X rail with mounting plates to add linear rails to my standard SO3

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Well by the time and money you spend to get an almost pro why not sell your current machine. I have sold a lot of shop equipment on Craigslist and got mostly what I asked. When you customize you are on your own with no support. With a stock pro the wheel has already been invented with no headaches. If you are good mechanically, electronics and tuning your controller then customizing would be good, but if you are not great at those things stick with an out of the box solution.

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How long?

Before the pro was announced I had already bought 600mm linear rails and the extrusion so I already had hundreds of dollars in parts plus all the other upgrades I purchased this past year so there was no turning back.

I’ll have to ask someone with a pro to measure theirs but they look to be about 6-8mm longer then the standard SO3 motor shafts.

can you tell me how many teeth the stepper pulleys have please? I found 15mm gt2 belt on ebay so my next task is to find the right gt2 pulleys. unless carbide3d comes out with a pro maintenance kit soon I will have to buy from a different vendor.

You might want to try Powge on AliExpress, they have an excellent range of GT2 belt and pulleys which seem to be of reasonable quality (and their belts seem to be used on the Pro as well).


Will do thanks!

I guess the pulley tooth count matches the stock SO3 just wider so I will mark and count the teeth on my machine and start looking.

(the tooth count should be 20, on the stock one)

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For those looking for belts and pulleys here are the links.


as for the pulleys I could only find 20t 3m versions that were 15mm wide and read they have 4 to 5 times the backlash so I am still hunting for suitable pulleys.

Thank you LiamN for pointing me in the right direction


Looks like I was wrong, the one set of pulleys I have here that didn’t come from Powge or Powge transmission parts store were the hard to find 20T GT2 15mm, they came from this vendor instead;

They seem perfectly decent quality, once you put a sensible length set-screw into them.

The 15mm GT2 20Tooth is unusual, I suspect because most applications looking for stronger engagement are going to use a larger pulley to get better belt grip on the pulley and reduce the belt stress from flexing. However, the Carbide3D design saving the costs and hassle of other cruft between the stepper and the belt kinda fixes the pulley radius if we want to keep our torque belt forces.

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Just curious here,
Can the controller be set for different size pulleys? = more or less steps per mm ?

Yes. You can go into the MDI screen and send different values to the grbl settings.


But if you do that the smallest step size in CM of 0.025mm may no longer cleanly step that multiple every time as it’s directly related to the angle of step on the motor, the pulley radius (tooth count) and the number of microsteps.

Also, if you increase the pulley size without gearing the stepper to the pulley the stepper holding and deflection torques will change. If this was combined with a larger stepper with more holding torque (bigger magnets) that might all wash out but possibly at the expense of top end speed and accelerations.

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For doing that see: