UGH! Spindle Bearings are Bad

D

David2011

H-M Supporter - Gold Member
H-M Supporter Gold Member
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May 19, 2022
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Last December I bought a dirty Index 645 mill that otherwise seemed to be in decent condition for the price. It has had some noise while running since I got the electrical box built, running a VFD. Right off the bat I ran just the motor with no belts. It's whisper quiet. The first pulley set off of the belt made some noise so I removed that assembly and gave it new bearings. It's only an intermediate pulley set that doesn't affect precision so I gave it standard grade Timken bearings. That made it somewhat quieter so I was happy enough for the time being.

There are 5 bearings in the quill and spindle and one or more of them clearly was an offender. I've been trying to nurse the machine along and continue to use it but in the last week or two the noise has gotten much worse. I pulled the drive sleeve and bearing assembly beneath the spindle pulley and gave the spindle a twist by hand. Yes, there was the rough rumble that was getting worse. I made a pin wrench to remove the threaded rings that set the preload and lock it in place but the lock ring didn't want to budge with the maximum pressure I was willing to exert. I would rather send it to Well-Index as is than mess up something and make for an even more expensive repair. The spindle drive bearings are not high precision so they were also replaced with standard Timken bearings.

In the process of cleaning up I removed about a half pound of nasty old grease that didn't even need to be there. Now I know why the spindle was leaking oil. It was all of that grease "sweating" out of the oil.

The quill and spindle assembly is out of the head and will be going to Wells-Index for an expensive visit. Bearings and installation runs just over $700. If there is runout in the spindle bore then regrinding it will run another $237.50. It's a painful amount of money for a hobby machine that generates no income but it's the only way to go. Letting Wells-Index do the repair should restore the machine to their new standard of 0.0002" runout. Glad I haven't sold my mill-drill yet so I'm not totally without a mill for the interim.
 
Nice that the manufacturer is still in business and offers this kind of support.

If I had the space and the money I’d get a brand new Wells Index.


John
 
If you haven't put new belts on, Sometimes the noise can be the belts. An easy way to check them I learned when I worked at Caterpillar is to spray the belts with a spray bottle that has a little bit of soap mixed into it while it running. My neighbor asked me to see if I could find the noise his engine was making on his motorhome, I listened to it and told him I believed it was the belts making the noise. He argued with me about it swearing he just replaced them not more than a year or 2 ago. I told him I would be back in a few minutes.

I went home and got my spray bottle and sprayed the belts while it was running and the noise went away. He went and got his record book and it had been 6 years since he had replaced them.

Before I tore the head open I would check the belts like I described. I know my BP clone's belts make noise and I need to change them. But I am not going to do it until I change the timing belt too.
 
jwmay said:
I think that’s a steal of a deal personally. It does suck to have to bear the cost, but it’s going to be awesome when it’s done, and last the rest of your life.
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Yes, the idea of having that part of the machine pretty much restored to factory new precision is a motivation and justification. I could just as easily have had the same problem if I had spent twice as much on a used machine. Good used machinery is hard to find around Houston.
 
Harry Knutz said:
If you haven't put new belts on, Sometimes the noise can be the belts. An easy way to check them I learned when I worked at Caterpillar is to spray the belts with a spray bottle that has a little bit of soap mixed into it while it running. My neighbor asked me to see if I could find the noise his engine was making on his motorhome, I listened to it and told him I believed it was the belts making the noise. He argued with me about it swearing he just replaced them not more than a year or 2 ago. I told him I would be back in a few minutes.

I went home and got my spray bottle and sprayed the belts while it was running and the noise went away. He went and got his record book and it had been 6 years since he had replaced them.

Before I tore the head open I would check the belts like I described. I know my BP clone's belts make noise and I need to change them. But I am not going to do it until I change the timing belt too.
Click to expand...
The first thing that I replaced on the mill was the belts. With the belt from the motor to the intermediate pulley in place and the one from the intermediate to the spindle pulley removed, it's whisper quiet. With the quill and spindle assembly on the bench, you could hear it across the room when I turn the spindle by hand at low speed.
 
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