Spindle is making an inconsistent noise.

My 2014 Sharp SVL2416SE-M is starting to make some extra noise from the spindle. Possibly bearing noise it started yesterday and seems to be getting worse. Can the bearings on the spindle be easily changed or is this something that must be done off site or by a pro? I have always done my own work but I am not a CNC machine tech. I am hoping it is not too spendy but it is what it is and I need this machine.

Besides noise, are there other symptoms?

Heat?
Bad finishes?
New chatter trouble?

Most smallish mills are a cartridge spindle design, but don't know about the Sharp. I've rebuilt a couple cartridge spindles, but prefer to send to a spindle shop. By the time you clean up an area and line up the required press and make various sleeves or mandrels, you usually have a bunch more time into it than you expected.

Fortunately there is an excellent spindle repair shop not too far away. C&M Precision Spindle is off highway 99 between Tigard and Sherwood. I have used them for over 20 years and they have done a couple tough ones that other shops failed at.

What does that usually cost? It is still cutting good but I have been getting a noise it is hard to explain it comes and goes it is hard to pin down everything is working good. I ran it at 1000 RPM with an edge finder and it sounded bad but then got better. I had made parts with it in the morning and shut it off came back about 4 hours later and when I ran it with the edge finder it sounded like it had a bearing noise but soon smoothed out I let it warm up for a bit at 2000 RPM before running a test part it all worked fine. I noticed yesterday the noise came and went but now it is more often. I may try and do a video.

Gundog is your spindle an air/oil type? If so is the reservoir out of oil? How hot does it feel after it’s been running?

Vanc that’s good to know, that’s 5 minutes from my shop

if your spindle is getting hot or the finish sucks your bearings are more than likely shot(but not always)
spindles run between 3k and 12k depending on what type and for what machine. Cartridge spindles are cheapest for the most part. the inline direct drive ones are more expensive. if your mechanically incline yes you can rebuild them but you need to knwo what to look for also. while some think you just pop bearings in and be done, its important you know what caused the problem to begin with.
Like a crash, oil issues etc etc. bearings will run about a grand give or take for a basic spindle. keep in mind that you can destroy a grand in just a few seconds if you dont know what your doing or what to look for.
your machine shouldnt have any bearing issues as its relatively new . which leads me to believe it was cause by a crash or not having oil if its oil bearings.
as you said it just started up.
that being said if the spindle isnt getting hot. look for a belt issue pulleys loose, motor bearing going out. if its direct drive then look at the coupler, they do break down after a while.its a small rubber piece like an water impellor on a outboard if it gets sloppy or loose they will sound odd.
other things to look at is something inside the head cover.
does it change sound when you move the z up or down? that can be cause by electrical noise in the machine, current draw too much ie another problem not a spindle.
make sure your cover bolts are tight those harmonics will sound like a spindle going bad as well.
Thru spindle coolant? washers/ seals could be bad.
unless you crashed it or beat the crap out of it or if its an oil bearing it could be a host of other things.
also if your finish is worse it could be belts or pullys not ness bearings. if the spindle gets hot more than likely your bearings are going.

DethloffMfg said:

Gundog is your spindle an air/oil type? If so is the reservoir out of oil? How hot does it feel after it’s been running?

Vanc that’s good to know, that’s 5 minutes from my shop

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It is oil cooled with a chiller the oil level is slightly low but above the low mark on the indicator window I would think it is OK since it is cold right now.

I warmed it up at 2000 RPM this morning no noise I sped it up to 4000 RPM and still no noise. I don't have anything to cut yet I am still designing a fixture to cut soon so I will see how it goes. I will pull of the sheet metal around the spindle to take a look at things this weekend.

I have not crashed the machine since I have owned it I have not even a broken bit. I do run it at 10000 RPM often when I am using it. I have only had it about 4 months.

He meant lubrication, oil/air or grease? Spindles are like cats, they have 9 lives. Don't panic over a noise. If it is the beginning of the end it could take years before you have to fix it, or it could be a lot faster. I have one that started making a noise after a crash 3 years ago, the noise hasn't changed and it still works fine.

DavidScott said:

....Don't panic over a noise. ...

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Exactly!

Look for the other symptoms like heat, endplay, runout, etc. When those start to occur then you need to look at a rebuild.

Again, I don't know Sharp machines but most machines are fine at max RPM for long periods. Particularly when equipped with an oil chiller.

Belt noise?

gundog said:

I warmed it up at 2000 RPM this morning no noise I sped it up to 4000 RPM and still no noise. I don't have anything to cut yet I am still designing a fixture to cut soon so I will see how it goes. I will pull of the sheet metal around the spindle to take a look at things this weekend.

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Had the machine been off for an extended period of time before you turned it on and it started making noise ? Maybe oil had drained down, and now that you have run it, they are well lubricated.
I know Sharp was pretty admin about running the warmup cycles, when I told them the machine will not be used every day.

Just like anything with bearings, I am a believer the cold starts do more damage than running them fast when they are nice and warm.

I have been warming it up before use each time but I have only had it 4 months I don't know if they ran a warm up procedure or not before I got it I am the second owner.

One thing to understand is noise will travel. Make sure it is the spindle and not something inline with it. I had a fan on top of my Fanuc spindle that was filthy and had a bearing that was bone dry. The fan would make random noise and often at higher RPM. After removing the fan assembly, cleaning it and repacking the bearing it has gone away.

If you have multigroove belt sheaves between motor and spindle they will sound just like a bad bearing if they are misaligned. Happened on our bed mill and everyone was talking teardown before I found a missing bolt on the twper lock sheave.

I have a sharp 2412 mini mill. I had the same problem with my mill.I would have bet my life the spindle was going out. Change the spindle belts.Even if they look like new like mine change them. The noise from my spindle got up to 90 decibels at 6000rpm. Changed them and it now runs at 70 decibels at 8000rpm.

Also some of the mills had misaligned pulleys the belt would ride to hard on the
pulley flange. The motor pulley had to be moved up or down.
Take the cover off turn the spindle touch the belt with a screw driver so the belt rides up the pulley off the flange ,see if this makes things quieter .

I took off the sheet metal today to have a look nothing is obviously wrong. The belt and pulleys are very hard to see they sit inside a huge casting I am not even sure after looking at it how I would adjust any alignment. I took a couple pictures with the sheet metal removed.