I have a 30 degree 1F, 1/4 dia. engraving tool in my 100mm x-carve. What I am seeing is a runout at the tip of the tool at high speed due to what I think is vibration. The reason I think it is vibration is if i remove the spindle from the x-carve and run it at 14000 rpm the tip runs true, but once I mount it in the motor mount I can see it vibrate out a lot. I would guess .020" or so. I checked all the rollers, belts, and screws, they all seem tight. What could it be? I am running the 24V spindle.
By it’s very nature a single flute tool is not balanced. I think when you hold the motor in your hand that your hand is dampening that out of balance. With the motor in the machine and held ridgid the same unbalance causes to collet adapter in a small shaft to oscillate and give you the run out you are seeing. The fact that the motor has cheap bearings does not help.
It may be time to upgrade to a better spindle if you want to do a lot of engraving that need close to zero run out.
Ok what is your recommendation ?
I guess that would depend on what your budget will handle. There are several ways to go. A lot of folks are moving up to the Dewalt 611 trim router. Others are moving up to a water cooled or air cooled 3 phase spindle with VFD.
As I have said before on the forum. What Inventables calls a spindle is just a cheap DC motor with a ER11 collet adapter stuck on a small diameter shaft that has cheap bearings and is prone to failure.
I don’t know where you are in the world so I don’t know what all options may be available to you