Indicating knurled surfaces

[whateg0]

I think you are too concerned with accuracy. Accuracy counts for more as speeds increase. Your grain mill won't or shouldn't be turning extremely fast. Instead of trying to get down to the tenth, accurate within a thousandth is probably more than enough. Chuck that knurled shaft in, get it close as you reasonable can, and turn the end down.

I don't think he can get it too accurate anyway, since knurls are often a bit inconsistent. But in this application, where the part has to rotate against another moving or non-moving part, any non-concentricity may cause the grain mill to not work well, or maybe not at all.

Dave

[whateg0]

... getting ... indicator replacement feet is not really an option. ...

Does your lathe not have a threading function? You can turn these little feet so easily. For light use, hardening isn't even really needed.

Dave

[atunguyd]

I think you are too concerned with accuracy. Accuracy counts for more as speeds increase. Your grain mill won't or shouldn't be turning extremely fast. Instead of trying to get down to the tenth, accurate within a thousandth is probably more than enough. Chuck that knurled shaft in, get it close as you reasonable can, and turn the end down.

You are very right, I am gearing down a 2800 rpm DC motor down to about 300rpm so pretty low speeds. That said my gears and bearing blocks are being 3D printed (too lazy to machine these) so I want to keep vibrations down as the plastic will fatigue fairly easily.

Where I am in this project is that I managed to chuck up the existing roller very close and turned the shaft down from 10mm to 8mm. This has removed all the shaft bend runout but left me with some that was a result of my inability to mount the roller perfectly concentric.
Things is not bad and only produces a small wobble on the gears. I will leave it this way and see if the plastic gears can handle the torque involved (milled 5kg last night without and problems). If they survive a few months I can then consider a more accurate solution that I can machine.

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