Milling machine - video

**tonyfoale** · Jan 13, 2026, 02:52 PM

Originally Posted by SteelCraft

MT3 spindle was dirt cheap on aliexpress, literally 50 USD. Back then I didn't know if whole machine will even work as mill and plan B was fancy drill press - that's all.

That is a pretty good reason. Did you ever measure the runout on that spindle?
You have built something way beyond a fancy drill press.

**tonyfoale** · Jan 13, 2026, 03:10 PM

Originally Posted by tonyfoale

The spindle change is a good move. I always wondered why you didn't pick R8 or iso30 instead of MT3.
There is a contributor on this forum "ThreadExpress" who did a very interesting comparison of R8 and iso30. He may have included a MT3 but I do not remember exactly.

Here is a link to the ThreadExpress video comparison between R8, TTS and iso30.

**SteelCraft** · Jan 15, 2026, 12:15 PM

Originally Posted by tonyfoale

Did you ever measure the runout on that spindle?.

Yes, I did it in the end of very first episode of this series. Needle barely moved in range of less than 0.01 [mm] inside taper.

**tonyfoale** · Jan 15, 2026, 01:29 PM

Originally Posted by SteelCraft

Yes, I did it in the end of very first episode of this series. Needle barely moved in range of less than 0.01 [mm] inside taper.

That is pretty good for a $50 spindle.

**SteelCraft** · Jan 18, 2026, 10:02 AM

Improved machine head build video:

**mccwho** · Jan 19, 2026, 09:44 AM

Originally Posted by tonyfoale

IIRC you have linear ball slides on the Z axis, that is very low friction. I am guessing but I do not believe this is a good match to a normal lead screw. Maybe you need a ball screw. Like I said this is a guess, but the forces provided by the slide friction from normal dovetails will relieve load off the lead screw and nut on the way down.

I am currently building a CNC surface grinder which with a change of grinding head to a milling spindle will also be a 3 axes mill. I am using linear rails and ball screws on each axis. However as it is a work in progress it is too early to come to any conclusions about vibration. I have my fingers crossed.

Here is an idea. On my Bridgeport mill I have added 4 assist springs to the knee to relieve load off the stock screw and nut. Here is post that I made A knee helper
maybe something like that would work for you???????

Awesome work!