Check your spindles

My Nomad developed a “clicking” noise over the past couple of weeks (before a 2+ week teardown…) It turned out to be in the spindle.

On the Nomad, the spindle chuck is pre-loaded into the bearings through a couple of Belleville springs. The only thing holding the preload is the two setscrews in the driven pulley from the spindle motor.

Setscrews really aren’t a reliable method of withstanding thrust loads–they are fine for transmitting the torque from the spindle motor but that is an order of magnitude lower force.

It turns out that my spindle pulley had backed off to the point there was clearance between it and the Belleville springs. The spindle had taken to spinning relative to the bearings, and the Belleville spring wore a groove in the aluminum pulley.

My spindle was damaged and loose in the bearings. It had spun and scored.

Fortunately, I had bought an almost identical ER11 spindle chuck when I was looking into building an auxiliary spindle for my Tormach. It turned out to be a perfect fit in the bearings.

I bought a Ruland balanced 8mm shaft collar which I put behind the driven pulley.

The clamp overhangs the end of the spindle a bit, but there is clearance under the Z axis block.

The moral of this is, check your spindle for endplay! Maybe even install the shaft collar as a preventative step…


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Hey @Randy, thanks for the post. As a beginner, I’m not really sure what to look for… Grab the spindle, see if I can push or pull it out of position? Are there some screws I should doublecheck the tightness of? Which ones?

@kjl, it’s not that the setscrews in the spindle pulley hub were loose. The Belleville springs had pushed them along the length of the shaft (overcoming the friction between the screws and shaft surface) until there was a clearance. Yes, just grab the spindle housing and try to push it up and down. If you do that with the machine powered up, the carriage will be locked in place so you can try quite a bit of force. But mine actually rattled.

In my own spindle design I was going to tap the shaft M8 and use a pair of thin M8 nuts (one as jam nut) to set the bearing preload through Bellevilles. But the shaft collar doesn’t need any modifications to the existing shaft.

If your shaft was loose, you would need to remove the spindle cartridge, loosen the pulley setscrews, and retighten the screws while pushing the pulley down against the springs. The need to remove the spindle cartridge is to be able to support the collet end while compressing the springs.

But mine might be a singular experience, given the general lack of “me too” responses. And I hope it is.


I had a similar issue with the larger pulley connected to the spindle motor. The setscrew let go just enough and made a spiral groove around the motor shaft until the pulley came off (actually jammed against the spindle mounting bracket. I caught it before major damage was done or belt damaged…
Personally I’ve always been untrusting of setscrews and want to see a flattened shaft or a dimple for the setscrew to sit in… perhaps they are “supposed” to only have a maximum holding force to act as a bit of a max-torque safety? Dunno if that is the design or not, but I’m suspicious anyways.
Of course, if I were born a few hundred years ago I’d probably be one of those guys who were suspicious of buttons being the devil’s work… but that’s just me.


Double. I think.

I noticed my spindle was getting hot. Too hot to touch. There is a +10° C difference between the bottom and the top of the spindle after about 30 minutes of cutting wood. The bottom was 59° C.

When my Nomad first arrived, the spindle would get “a little warm” no matter how much I used the machine. Obviously, something has changed.

Tonight there was some clicking noise. I believe the collar is farther from the top of the spindle.

Does all that seem familiar? Does it seem likely I have crossed paths with the same problem?

Other than adding the shaft collar and changing the spindle chuck, what did you do to get your machine back in business?