Upgrading stepper motor for 80mm Spindle

Hey everyone,

Ordered the 80mm mount as I have a 80mm spindle I’d like to try. Given the weight, considering upgrading the Z-axis stepper and was wondering if there is any guidance on what size stepper I should look at. Given the buildbotics should be able to handle most of the comparable Nema 23 steppers of larger size, if I am ready correctly, seems like one of these should work:


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This should be more than adequate. These are similar steppers to those used by AvidCNC on their machines. Their smaller spindle is lighter than the one you mentioned, but their Z axis mounting system is heavier than the 1F. I am not using the 1F controller, so am not familiar with the drives or PSU it uses, but as long as the motors have the voltage and amperage they need they should work. Keep in mind you will need to order a new shaft coupling as I believe the stock steppers use 1/4” shafts.

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I was wondering the same thing. Did you upgrade the motor? I feel like the heavier spindle is losing fine detail and that maybe it needs a larger z motor. Would the settings have to be changed in the onefinity software with the addition of the larger motor?
Thank you

Hi, have you see a loss in detail with the heavier spindle, or are you saying you think you will? I’m keen to find someone with experience in using an 80mm 2.2kw spindle.

I am not understanding how a stepper motor would effect detail? From my experience when the stepper motors cant go as fast as the code is asking it too it just doesn’t get to those speeds. It runs slow but no detail or accuracy is lost. For example if you have your machine set to 350ipm and there are a lot of small cuts and turns. The machine will never actually make it to 350ipm it just goes as fast as the stepper motors will take it because there is not enough room in the cut to accelerate to full speed. When you get to a turn the machine has to decelerate to turn and the then accelerate back to speed after the turn. If the cuts are small then full speed is never achieved. Bigger stepper motors should just mean that it will get to those speeds faster.


But if the z is struggling to life the much heavier spindle might it lose some detail in the z motion?

I don’t have a lot of experience as I just switched to the larger spindle. I have only run one job and I did lose detail. I have run it multiple times and at different speeds with the same results. When using the makita router and mount this did not happen. I might switch back to the makita and re run the program and see the results again. This is why I’m wondering if the z motor may be struggling just a small fraction and causing this result.


Here’s what I’ve done so far. I got the honking big 114mm 425oz.in/3Nm stepper and installed it on my z-axis with my existing 65mm spindle. Everything seem to work fine without any other changes to software or my set up. I thought it might be a little overkill but hard to tell until I get the heavier spindle installed.

I started thinking about the weight differential (Not only the spindle but whatever larger stepper I put on the Z axis) And thought that upgrading the other steppers might be a good idea as well considering that the Y-axis would now be carrying all the weight of the increased package. So I bought a bundle of 3 269oz.in/1.9Nm steppers.

The spindle mount came yesterday and today is my reconfiguring day.To start, I’ll be just upgrading the Z-axis spindle stepper to one of the 269 oz steppers and see how that does. Over time I’ll upgrade the X and Y steppers as I have time.

Here’s a photo of the three different stepper sizes and the 65 and 80mm spindles. On the left is the original stepper, then the 269 then the 425.

I’ll let you know what I find out.

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@Bumpski can you describe your detail loss more. I have my 80mm mount on the way and plan to start testing the larger spindle when it gets here.

Funny, you not only aligned the spindles and the steppers by their size, but the feet also


Hey Patrice,

now that the X-50 Rails are out, and the 80 mm Spindle Mount, which makes sense together, I wonder if the larger 1616 Ball Screw of the X-50 Rails, the thicker 50 mm rails themselves and their much larger linear bearings would be the good thing for a heavier Z Axis Gantry in order to bear heavy spindles? (And a larger stepper too then of course)

The Z Axis is the only one that constantly has to bear something against gravity. And the spindle weight is positioned off-axis

Making a sign with a patch that had very small words in the middle of it. With the makita I could read it easily and with the larger spindle I can not really make out the words. On the entire job this was the only issue I had. Overall it was much smoother and quieter but I would like to figure out what is causing this.

Did the 425 motor fit right into where the old one was or did you have to make some modifications to make it fit?

I have an 80mm 2.2KW spindle on my machine. Adding to this, I have upped my Z micro steps from 16 to 32 and the stock Z axis motor handles the larger spindle just fine. Here is the video I posted in the 1F Facebook page showing the machines behaviour with the larger spindle and finer Microstepping adjustments

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@alldaysammyj have you been able to make any cuts with the new setup and also curious if you are noticing any loss of detail or speed issues during the cut?
Second does the added microstepping add significant time to your projects?

That, my friend, was hilarious! :rofl:


unfortunately you posted a link to a closed-web, members-only resource. Can you upload it to a public webspace?


Hey Mike,

loosing detail on the work after a spindle upgrade like this is surely not the result one awaits or hopes for! I find this a little bit worrying. I am sure it’s not just me who would like you to investigate this.

There could be different error causes.

I’m with you questioning whether some components of the Z Axis Gantry and Mount could be overburden, including stepper motor. But before suspecting one of the Onefinity’s components I would make sure that everything is in order with your spindle and with your tool. Can you check true running, first at spindle axle, and then at tool shank, using a dial gauge like explained in this video?

Btw, do you have X-35, X-35 with “stiffy”, or X-50 Rails?


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I have the x35 with stiffy rail currently. I could try that possibly with the gauge however I don’t think there is wobble from side to side in the spindle. It looks to be up and down movements that are out of detail in the very fine details. I will keep working on it when I can, but I’m not technical in the troubleshooting field. I’m new to cnc and may just put the original spindle on that had no issues until some other upgrades are also available.

A stepper motor usually does not struggle for life. If it has to move against a force that is too high, it looses steps. The controller has the ability to recognize that.

Also Onefinity stated here that a heavy spindle using 80 mm mount would be no problem. The 80 mm mount has not been released without longer testing.

I would suspect that there is some backlash/clearance somewhere.

What spindle do you use?

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