Advice for cleaning spindle bearings

TomBoctou · Nov 29, 2017

I took the bearings out of an Ames horizontal mill (1AM spindle) with the intent of replacing them - they're crunchy with decades of dried grease. I don't know that they're not pitted, but the visible parts look good.

They're common cheap bearings - New Departure 5209 double row and 6209 single row. Or they would be common and cheap except that they're high preload high precision (5209-X5).

They're still tight, but I can't get them smooth. The 6209 has a non-removeable shield to keep me from getting a brush or high pressure stream in, and the double row has a similar problem due to being double row.

I was going to try soaking them in lacquer thinner for a week in the hope that that would loosen the schmutz. If that fails then I was going to try hooking them up to some slow motor - something like a cheap hand-held mixer (like used for cakes) - and rotate them slowly for another week in kerosene or hydraulic fluid.

Anyone got any better ideas? I'd happily replace them, but I'm pretty sure they'll be well north of $100 each, so it's worth trying to save the old ones.

This is the overarm version of the Ames mill - it's the same bench-top size as the other Ames millers, but it has much beefier bearings than the non-overarm 1AM spindle version.

Larry Dickman · Nov 29, 2017

I would try sandblasting them.

TomBoctou · Nov 29, 2017

Larry Dickman said:
I would try sandblasting them.

Hmm, I hadn't thought of that. Should I heat them up cherry red first to burn the grease off?

B-Mathews · Nov 29, 2017

tom_boctou said:
Hmm, I hadn't thought of that. Should I heat them up cherry red first to burn the grease off?

Yes! Is that that a given? Sorry LOL

dkmc · Nov 29, 2017

Keep right on truckin with your original idea of replacing them.
The only way you're getting in to get the goo out is by taking off the shield.

rons · Nov 29, 2017

tom_boctou said:
I was going to try soaking them in lacquer thinner for a week in the hope that that would loosen the schmutz.

It should not take days but minutes. You will know when the lacquer thinner changes color from clear to dark. Soak them, lightly spin, soak and repeat.

You can force new grease inside the shields with the palms of your hands. There are also methods to ram new grease onto one side and the excess comes out the other side. Bearing grease press tool.

JST · Nov 29, 2017

New Departure, in their bearing handbook, actually suggested a water base floor cleaner to soak them in for cleaning, "Oakite", which I understand (but do not know for sure) was a lye-containing heavy duty floor cleaner. That would presumably clean out the grease, especially if the solution was heated.

No idea what that translates to now, oakite products seems to be part of Chemetall, itself part of BASF

Chemetall North America

AlexO · Nov 29, 2017

tom_boctou said:
I took the bearings out of an Ames horizontal mill (1AM spindle) with the intent of replacing them - they're crunchy with decades of dried grease. I don't know that they're not pitted, but the visible parts look good.

They're common cheap bearings - New Departure 5209 double row and 6209 single row. Or they would be common and cheap except that they're high preload high precision (5209-X5).

They're still tight, but I can't get them smooth. The 6209 has a non-removeable shield to keep me from getting a brush or high pressure stream in, and the double row has a similar problem due to being double row.

I was going to try soaking them in lacquer thinner for a week in the hope that that would loosen the schmutz. If that fails then I was going to try hooking them up to some slow motor - something like a cheap hand-held mixer (like used for cakes) - and rotate them slowly for another week in kerosene or hydraulic fluid.

Anyone got any better ideas? I'd happily replace them, but I'm pretty sure they'll be well north of $100 each, so it's worth trying to save the old ones.

This is the overarm version of the Ames mill - it's the same bench-top size as the other Ames millers, but it has much beefier bearings than the non-overarm 1AM spindle version.

There is always the option of leaving them as they are. A half good cleaning job will just dislodge rubbish and later cause accelerated wear. I'd just add some wheel bearing grease and use them until I can buy new ones. A lot of the "grit" you feel is from the ball retainers - not hard enough to cause damage and it'll be eventually pushed out of the way.

TDegenhart · Nov 29, 2017

I did some in an ultrasonic cleaner using solvent. Run for a while, gently clean out the goo, put them back in for another while, repeat until the bearing come out clean. Amazing how much gunk that can collect in a bearing. When done, I checked the bearing under a microscope and could not find any damage.

Tom

Richard King · Nov 29, 2017

I just Googled those bearings and found some bearings on Ebay. Looks like new surplus on there is about $100.00 for both. Have you checked new bearing prices from a Local Industrial supply? I figure if I have a bearing up I just replace. it. Fafnir 52�9 WD, 52�9WD, Double Row Ball Bearing, | eBay

These are the guys I buy my bearings from. They sell new for wholesale prices.
Register

billzweig · Nov 29, 2017

TDegenhart said:
I did some in an ultrasonic cleaner using solvent. Run for a while, gently clean out the goo, put them back in for another while, repeat until the bearing come out clean. Amazing how much gunk that can collect in a bearing. When done, I checked the bearing under a microscope and could not find any damage.

Tom

I do the same. Sometimes an oven cleaner like "Easy Off" can be used to remove the polymerized gunk after solvent cleaning.

JST · Nov 29, 2017

billzweig said:
I do the same. Sometimes an oven cleaner like "Easy Off" can be used to remove the polymerized gunk after solvent cleaning.

Same as purple cleaner, or other lye-based cleaners.

Spruewell · Nov 29, 2017

Sounds like you will be spending nearly as much if not more time and money trying to salvage these bearings than they are worth. And after all that time, effort and money spent, you will still have used bearings that may or may not have a bunch of contaminates in them (yes, solvents can be contaminates too). If you intend to put this machine back together and run it for more than a couple weeks, I would highly recommend just biting the bullet and buying the new bearings. They don't seem all too over-priced, and having good reliable bearings is priceless in a machine tool

TomBoctou · Nov 30, 2017

Richard King said:
I just Googled those bearings and found some bearings on Ebay. Looks like new surplus on there is about $100.00 for both. Have you checked new bearing prices from a Local Industrial supply? I figure if I have a bearing up I just replace. it. Fafnir 52�9 WD, 52�9WD, Double Row Ball Bearing, | eBay

These are the guys I buy my bearings from. They sell new for wholesale prices.
Register

That's not the same bearing - that's ABEC 1 with C3 clearance (extra loose). I've already got one of those, new, and it's got a lot of slop in the inner race (it wiggles). The ones I'm trying to replace are high preload with no slop in the inner race - spindle bearings, not wheel bearings.

TomBoctou · Nov 30, 2017

Spruewell said:
Sounds like you will be spending nearly as much if not more time and money trying to salvage these bearings than they are worth.

Not if it's relatively easy to clean them, and I still haven't even figured out if they're still made or what they might cost. My experience with precision spindle bearings is that they're not cheap.

Spruewell said:
And after all that time, effort and money spent, you will still have used bearings that may or may not have a bunch of contaminates in them (yes, solvents can be contaminates too).

I've never bought a new lathe or mill, so the same could be said of any machine tool I've got. Throwing expensive stuff away without bothering to find out if it's any good doesn't make sense to me.

Richard King · Nov 30, 2017

tom_boctou said:
That's not the same bearing - that's ABEC 1 with C3 clearance (extra loose). I've already got one of those, new, and it's got a lot of slop in the inner race (it wiggles). The ones I'm trying to replace are high preload with no slop in the inner race - spindle bearings, not wheel bearings.

Then buy some new ones or keep looking for the ones you need on Ebay. Also call Baker Bearing. They buy surplus bearings and usually are 1/2 the price of new. They may ask you to buy them through a bearing house like BBI the place I referenced before. Baker Bearing: Ball Bearing Supplier Baker Bearing Company

I have also ad good luck buying new surplus bearings from this company too. Ball Bearing Distributor - Precision Ball Bearings | MMB Bearings

AlexO · Dec 1, 2017

tom_boctou said:
I've never bought a new lathe or mill, so the same could be said of any machine tool I've got. Throwing expensive stuff away without bothering to find out if it's any good doesn't make sense to me.

You could drill a 1mm hole in the 6209's shield and use that to pry it off. I do this often. Then, clean and regrease. I clean bearings in paint thinners and sometimes they need a day or two of soaking and lots of compressed air. In the end you won't get them as smooth as new but that doesn't mean they're not just fine. Also, depending on the age of your machine new bearings in a normal/C2 could well be as good or better as precision versions from 50 years ago. Most of the time they're all made together and just measured/selected.

JST · Dec 1, 2017

The ND double row such as he mentions are "negative clearance" , or "preloaded internally". Any clearance in the replacement will cause chatter unless you find a way to preload it externally.

The tail bearing may be less critical, but a C3 might be too sloppy even there. BTDT.

TomBoctou · Dec 1, 2017

JST said:
The ND double row such as he mentions are "negative clearance" , or "preloaded internally". Any clearance in the replacement will cause chatter unless you find a way to preload it externally.

The tail bearing may be less critical, but a C3 might be too sloppy even there. BTDT.

The tail bearing appears to be preloaded too. It seems like externally preloading a double row bearing would defeat the purpose of having a double row bearing.

The bearings aren't fully marked describing what they are. The front one has "X5" hand engraved, which means medium preload ABEC 5 (not extra preload as I previously said), but the tail one is labeled "3209" on the inner race and 77509 on the shield. It is certainly not a 3209, but it is a 77509 (6209 in standard parlance).

I'm thoroughly confused now.

JST · Dec 1, 2017

tom_boctou said:
The tail bearing appears to be preloaded too. It seems like externally preloading a double row bearing would defeat the purpose of having a double row bearing.

....

Yes it does. When I replaced one, the machine maker supplied me a C3 clearance, even though they knew it was for a spindle. That was of course a disaster, I found what they had supplied after installation when it chattered so badly it nearluy tore loose from the mountings. They basically blew me off, and wanted even MORE money (the one they shipped was not cheap) for one that they would NOT guarantee was any better.

I externally preloaded with a supplementary deep groove bearing and belleville washers. It was a case of "this thing has to work", and since they were not helping, I made it work. It still works. Yes, I am certain one set of bearings is flapping around in there, but that is just what happens.

Advice for cleaning spindle bearings

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