UGH! Spindle Bearings are Bad

D

David2011

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
May 19, 2022
Messages
672
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.
 
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.
 
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.
Click to expand...
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.
 
Update: It took me a while to get a crate built to ship the quill and spindle assembly, More accurately, it took me a while to get the table saw and the area around it cleaned up enough to use it. I'll add details about the crate build later.

The package was shipped via UPS using Pirate Ship and it was insured as recommended by Wells-Index for the replacement value of $5,000, the maximum for Pirate Ship. This was Pirate Ship insurance and not UPS because I had packages lost previously, apparently delivered to the wrong address and because the carrier showed that they had been delivered they would not pay. The weight was just under 27 pounds and with insurance the shipping from near Houston to Wells-Index in Michigan was about $77.00.

The package arrived as expected this past Monday and they immediately started working on it. Mark said the bearings were toast which was no surprise. This morning he called and wanted to know if I wanted the collet pin replaced. I had assumed that the spindle had been reground from B&S #9 to R8 because I didn't find a collet pin but it turns out that it had been sheared off. For the small sum of $13.00 I get a new collet pin. The spindle was being reground when he called. He said that it had .0015" runout which was what I had measured as well. He expected that it would be shipped back to me tomorrow (Wednesday).

I'm really excited to have this work completed and done right. The rest of the mill seems to be in pretty good condition after using it for a few months so this is as close to getting a new full sized mill as I expect to get. All of the other bearings in the head have already been replaced so it should run very quietly.
 
It’s Saturday evening and I just unpacked the spindle and quill from its shipping box. I shipped it on Thursday, 6/20 and today is 6/29. Great service! It looks and sounds so much better. The inside of the spindle looks like new after being re-ground to factory specs; .0002” or better TIR.

A few days ago I opened the power down feed gearbox. There was grease in it that was as hard that I thought it was broken cast iron initially. The remaining grease looks like primordial ooze. It took several hours to get it cleaned up and make the shaft that controls up/neutral/down move freely. I really want to pull that shaft and the associated gears out to clean the insides but if I can’t figure out how, it is still going to work again.
 
Here's the ooze that greeted me when I pulled the cover off of the down feed gearbox.

IMG_6587.JPG
 
The spindle and quill are back in the mill and everything but the downfeed linkage is installed. Honestly, I didn’t know a mill could be as quiet as this one is now. It’s almost silent while running. I’ll install the remaining linkage today and start tramming. Maybe even make some chips. Can’t wait to see what the surface finish is like.
 
You must log in or register to reply here.
Back
Top