[yantra3d]

What sort of runout are you guys getting with your x3 mills? Has anyone tested to see how accurate the spindle is "out of the box"?

I recently started running my mill and after some minor cutting I visually noticed excessive runout so I tested it with a dti on the ID and was shocked to see it was out by .01!

After loosening the top bearing block assembly and tapping it around a little I was able to get it down to .002 but this still seems like too much to me. I am seriously considering pulling the spindle from the mill but before I do I would like to know what sort of accuracy to expect so I don't waste time trying to fix something that may not even be broken.

I'm also suprised at how much deflection there is in the spindle, head, and column. Just a slight push on any of these three will have a major effect on the indicator (~.008). I guess I expected more rigidity from this little mill. :|

[yantra3d]

Well I guess I'm off to pull the spindle... .002 is just too inaccurate to live with and I can only assume that the runout should be less. It would be great to know a target figure that I could strive for but I guess I'll have to go it alone.

I also wanted to mention that there is a lot of play between the spindle and the quill housing that can be detected by pushing back and forth on the top (spline) and bottom of the spindle. And yes, the quill is fully locked.

Does anyone else have this slop in the spindle? Is this to be expected on the x3?

[ihavenofish]

i dont have an x3, but i have a kx1 cnc made by sieg. my spindle runout on the taper is a bit under .001"

i dont know if .002" is bad for a stock x3, but from what ive seen in peoples conversions, its usually the roller bearings that cause much of the innacuracy. my mill for some reason has angular contact bearings instead.

[yantra3d]

Hey thanks for the response... I appreciate that!

I pulled the spindle, mounted it to my table and setup indicators on both the inner taper and outer housing so that I could adjust the preload on the top bearings. I noticed that the ground washer between the c-nut and the bearing was no where near flat so I carefully lapped it on my surface plate and then lightly lapped the c-nuts before attempting to adjust the preload.

I was able to get the runout down to within .0005 with a finger tightening of the nuts. I then mounted the spindle back in the head and tested the runout and it was down to within .0003". The play or slop I was experiencing has also disappeared so it looks like we're back in business.

He whole endeavor took less than 2 hours to complete. Needless to say I am now satisfied.

[ihavenofish]

Hey thanks for the response... I appreciate that!

I pulled the spindle, mounted it to my table and setup indicators on both the inner taper and outer housing so that I could adjust the preload on the top bearings. I noticed that the ground washer between the c-nut and the bearing was no where near flat so I carefully lapped it on my surface plate and then lightly lapped the c-nuts before attempting to adjust the preload.

I was able to get the runout down to within .0005 with a finger tightening of the nuts. I then mounted the spindle back in the head and tested the runout and it was down to within .0003". The play or slop I was experiencing has also disappeared so it looks like we're back in business.

He whole endeavor took less than 2 hours to complete. Needless to say I am now satisfied.

wow. thats not bad at all.

[yantra3d]

I say .0003" but it's more of a guess since my dti only divides by .0005 and it's bouncing back and forth between one division. It's probably safer to say that it's less than .0004" but greater than .0003".

Regardless I'm happy to have that problem corrected... now I can move ahead with my build. These delays are killer but I keep repeating the buddha's words like a mantra on this project, "Ambition is like love, impatient both of delays and rivals". (If only it helped!)