Noise from spindle on Leadwell V-40

[SRT Mike]

I was running a job on Friday and towards the end, there was a strange buzzing sound, different than the normal cutting sound. I shut the machine off and figured I'd look at it today. I ran the spindle at 500rpm - sounded OK. all the way to 4000rpm (what I machine at), sounded OK.

But, I ran another part and a few minutes into a 30 minute machinining cycle, the noise was back... I noticed that when I turn the spindle one direction by hand, every 4th rotation of the spindle nose or so there is a "grinding" feel. It feels just like a bearing.

But it's not every turn... only every few turns. So maybe it's a bearing in the motor and not the spindle? Or maybe a bearing on a pulley?

I am not sure if it's best to try to fix this myself or call in the pro's. I've rebuild a hydraulic actuator on my lathe, and installed axis bearings on this mill, so I am not inexperienced mechanically, but when I hear people talking about shimming to tenths and being super duper careful with spindles, I wonder if it's better to call in a pro?


I also don't understand why the noise in the spindle only comes every few rotations - unless the grinding feel isnt' actually from the spindle bearings. And I don't understand why it only grinds when I rotate in one direction and not the other?

Any ideas or tests I can do to try to narrow down the problem?

Anyone got experience with a Leadwell V-40 spindle? The machine is a 1995 model.

[avtechmachine]

Hello Mike,
It sound like noise from spindle belt?
Ahn Vuong

[SRT Mike]

Thanks for the reply... actually I just finished running a job and it was right back to sounding crappy again... but now when I rotate the spindle it grinds the whole way around and it sounds like it's coming from pretty close to the spindle nose... so I am guessing the lower bearings.

I've heard of people rebuilding spindles... but if I remove the spindle, aren't the bearings exposed anyway? I mean, it seems to me that if I am already taking that out, isn't it just a case of replacing bearings? Is it a job do-able by a person in a few days? Or is this something I should call the pro's in for?

Any ideas what this may cost me? I am hoping it's not going to cost more than $1-2k... fingers crossed!

[avtechmachine]

If the spindle bearing lube by oil you should able to change it your self but if it is grease bearing then you should call the pro's.
Max. 4000Rpm I guess it is oil lube.
I am not sure how much it cost but count on above $2,300
Ahn Vuong

[SRT Mike]

Originally Posted by avtechmachine If the spindle bearing lube by oil you should able to change it your self but if it is grease bearing then you should call the pro's. Max. 4000Rpm I guess it is oil lube. I am not sure how much it cost but count on above $2,300 Ahn Vuong

It has a max spindle speed of 6k rpm. I run at 4k just because I run the machine about 6+ hours a day constant (lots of profiling work - but all in plastic, so pretty light duty), so I figure keeping it to 4k most of the time would prolong spindle life.

Your price estimate of "above $2300" is that just to replace bearings? That seems high unless the bearings are very expensive. I've heard that a whole new spindle on a Fadal is around $3k... and bearings for the X and Y axes on this machine were $400. The machine shop next door told me they have had spindle bearings done and it's roughly a days work.

Or perhaps it's just very expensive bearings?