[Bwana Don]

We smacked our BT40 Kitamura pretty hard. I threw a toolholder up in the spindle and it checked .002 tir runout. I ordered a 40 taper testbar in order to accurately measure the runout. It will be here in a couple of days.

I didn't feel anything in the spindle like a burr etc.. I don't hear any unusual noises either.

My question is; How do you check for a bent spindle? Am I on the right track here? Any advice is greatly appreciated.

Thanks

Don

[keebler303]

If the runout gets worse the farther you get from the spindle, it is bent. I would check the toolholder in another machine to make sure it is good, then check the runout near the spindle nose and then again at the end of the bar.

Matt

[fizzissist]

[underthetire]

Mark the high spot with a Sharpie or something, if the high spot is in the same place every time, you can have the taper re-ground in place. If it changes position, you lost a bearing.

[Bwana Don]

Well the Briney test bar came in. The certification says it's accurate to .00015 at almost 10".

The machine checks .001 at 1" from gage line and .0024 at 10" from gage line. The high spot repeats every time also. I don't feel any funny business in the bearings when I turn the spindle by hand either.

I'm going to call my machine repair guy and let him know what's going on. I'll call Spindle Regrinding Services and get a quote too.

Thanks for the help guys,

Don

[keebler303]

You might get by with a taper regrind but if you smacked it that hard I'd say there could be some undetectable damage to the bearings. The damage could show itself at any time. Would be a shame to regrind the spindle only to have the bearings fail a week later.

Matt

[Big Daddy]

We smacked our BT40 Kitamura pretty hard. I threw a toolholder up in the spindle and it checked .002 tir runout. I ordered a 40 taper testbar in order to accurately measure the runout. It will be here in a couple of days.

I didn't feel anything in the spindle like a burr etc.. I don't hear any unusual noises either.

My question is; How do you check for a bent spindle? Am I on the right track here? Any advice is greatly appreciated.

Thanks

Don

I'm sure you have already had lots of great answers for this but anytime you experience anything like this in the future, go get a mag base with a .0001 indicator on it and place it on the table/vise etc. with the stylus up into the spindle bore. (Move your table in to position then bring your head down until the spindle bore makes contact with your indicates stylus.) Then turn your spindle by hand and check the readings. If you see something greater then .0002 YES you in fact bend the spindle. Typically in a Kitamura you'll see something far less more like .00002 and that's a maybe. Rarely do you see anything beyond .0002 in CNC's these days they're all built pretty nice.