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JoeLee
08-19-2009, 09:09 AM
Was wondering if anyone has had any experience taking one of these apart. It's tricky to get the spindle out and back in. Anyone know what type of material was used for the seals. The manual calls it Playa-Seal. I think that name was coined by Fafnir but they say no. The seals look like a Mason jar seal about .025 thick. I would like to know what the material is. Also what is the best type of grease to repack the bearings with?? Please don't say Kluber, I don't want to mortgage the farm to buy a tube. Originally the old sodium soap based grease was used and lasted for years but it's no longer made.

TNX..... Joe

lazlo
08-19-2009, 10:58 AM
I'd love to hear an answer on this. I have the same motorized workhead, with crunchy bearings.

It looks like the spindle is meant to be pressed out with a hydraulic press?

I have the parts diagram for it somewhere, but it wasn't obvious how to disassemble it...

JoeLee
08-19-2009, 02:18 PM
When you press the spindle out the inner seal retainers come with it. You have to be careful pressing through the balls, not to put too much force against them or you may dimple the race. They are precision spindle bearings. Make note of the asteric or burnish marks on both inner and outer races because the bearings have to be installed in that same way.

lazlo
08-19-2009, 02:57 PM
When you press the spindle out the inner seal retainers come with it. You have to be careful pressing through the balls, not to put too much force against them or you may dimple the race. They are precision spindle bearings. Make note of the asteric or burnish marks on both inner and outer races because the bearings have to be installed in that same way.

Thanks Joe! I actually found a replacement set of bearings on Ebay, but I doubt I can replace them and maintain the original concentricity, since the spindle was ground in the original bearings. I'm hoping that just washing the bearings out and repacking will fix the crunchyness.

Mobilith SHC is an excellent bearing grease that's relatively inexpensive (at least, compared to Kluber). MSC carries it in various grades. I'm not sure if a motorized workhead would want NGLI 1 or 2 grease -- you might try calling KO Lee (or whoever owns them these days)...

pcarpenter
08-19-2009, 03:41 PM
I have some of the mobilith SHC and it's not too bad, but is closer to an NLGI2 if I recall correctly. I think it's main application is motor bearings etc, and it seemed to suffer from the same oil separation on sitting that plain old Mobil1 chassis grease seemed to exhibit.

If you want a really high-grade synthetic NLGI1.5 bearing grease without paying Kluber prices, Mobilgrease 28 is one that is MIL spec rated for helicopter rotor bearings, aircraft jack screws etc. I repacked the spindle bearings in my bridgeport with the stuff and both because it's a 1.5 and because it's synthetic, I don't have problems with thickening even when I let the shop go cold in the winter. The stuff seems to resemble the stuff that was originally used by Fafnir, too...at least in appearance. It's very dark red and semi-transparent.

The reason I mention this is that it can be had pretty reasonably. I think I paid $13something for a tube from an aircraft supply place that does mailorder. They inadvertantly sent me a case instead of a tube and they wanted to know if they could sell me the rest of the case at the case price. I should have said yes and sold it to guys here doing spindle bearings as it would probably be cheaper than a tube at a time.

Here is the product:

http://www.mobil.com/Canada-English/Lubes/PDS/IOCAENGRSMOMobilgrease_28.asp

Here is where I got it. Looks like it's now $17 a tube but that's a lifetime supply given the sort of esoteric stuff that merits its use:

http://www.eliteetc.com/mob28sin125o.html

JoeLee
08-19-2009, 07:20 PM
Lazlo,

If the bearings are rough, pitted etc. you'll end up with the same feel even after cleaning and repacking them. I don't know if the spindles are ground in place or not. The inner bearing race is marked with a dot to indicate high point of ecentricity, also the end of the spindle is marked with an (X) make note of these when you take the bearings out. The outer races are also marked with a dot, both outer races should be installed at the same location relative to the housing. Example both outer race dots line up at the 1 o-clock position on each side.
The spindle TIR is .0002 which mine is. I would give it a shot and put the new bearings in since you have them.
Several years ago I spoke to Pius Hier at KO and he said that Lubriplate EMB grease was a good choice for spindle bearings. About $8 per tube.
Hope thei help.

Joe...........................

lazlo
08-19-2009, 08:59 PM
I have some of the mobilith SHC and it's not too bad, but is closer to an NLGI2 if I recall correctly. I think it's main application is motor bearings etc, and it seemed to suffer from the same oil separation on sitting that plain old Mobil1 chassis grease seemed to exhibit.

Yep, I use it for non precision bearings, and agree with all of the above.


If you want a really high-grade synthetic NLGI1.5 bearing grease without paying Kluber prices, Mobilgrease 28 is one that is MIL spec rated for helicopter rotor bearings, aircraft jack screws etc.

Here is where I got it. Looks like it's now $17 a tube but that's a lifetime supply given the sort of esoteric stuff that merits its use:

http://www.eliteetc.com/mob28sin125o.html

That's a good find -- thanks for that, I bookmarked it. For spindle bearings I have a tube of Kluber Isoflex that a kind soul here sent me. I should note that Kluber Isoflex NBU 15 is NGLI 2. Don't know if the thicker grease makes that much of a difference for low-speed machine tools like a Bridgeport or especially a motorized workhead...

oldtiffie
08-19-2009, 10:08 PM
Lazlo.

If that work-head were mine, and if I had replaced the bearings - very carefully as said previously - I'd use my Tool-post grinder and "take a (light) lick" from the bore to true the bore up.

I'd use a "test bar" - similar to my arbor for balancing my Surface Grinder wheels/hubs - to both "blue" the bore in and to see that it was not "skewed" at say 2" out from the taper:
http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Wheel_balance1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Wheel_balance2.jpg

I have some excellent arbors that double as test bars for the motorised work-head on my (Chinese - of course!!) universal grinder. I don't have pics of it but will post some later.

As good a test bar as I've seen has to be the MT or R8 and other tapered milling cutter arbors for the spindles in vertical milling machines. They make excellent arbors for grinding horizontal milling machine (type) cutters as well:

http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/Stub_arbor1.jpg

lazlo
08-21-2009, 06:03 PM
If that work-head were mine, and if I had replaced the bearings - very carefully as said previously - I'd use my Tool-post grinder and "take a (light) lick" from the bore to true the bore up.

Good point Mick. I'm going to try to press the head apart this weekend...

Joe asked me to post these pictures for him. Here's the B943 spindle and housing:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Workheadspindle1.jpg

http://i164.photobucket.com/albums/u15/rtgeorge_album/Workheadspindle2.jpg

http://i164.photobucket.com/albums/u15/rtgeorge_album/Workheadhousing.jpg

TGTool
08-21-2009, 06:26 PM
... Anyone know what type of material was used for the seals. The manual calls it Playa-Seal. I think that name was coined by Fafnir but they say no. The seals look like a Mason jar seal about .025 thick. I would like to know what the material is.

TNX..... Joe

It sounds like what I've known as a Nilos ring. That may be a brand name. Here's a link to an explanation http://mdmetric.com/prod/nilos/nilos3.htm .

I think they can be had through bearing suppliers.

Jan

JoeLee
08-21-2009, 07:41 PM
The Plya Seal is not a Nilos Ring. If you look at my pictures of the spindle you will see the the black rubber rings which are .025 in thickness and resemble a Mason jar seal. Maybe EPDM.?? I sent one to a gasket and seal company and they couldn't identify it.

JL.............................

lazlo
08-21-2009, 10:33 PM
If you look at my pictures of the spindle you will see the the black rubber rings which are .025 in thickness and resemble a Mason jar seal.

Joe, could you cut one out of Nitrile rubber sheet? I just checked, and the thinnest that McMaster carries is 1/32" (.03") -- is that close enough?

http://www.mcmaster.com/itm/find.ASP?tab=find&context=psrchDtlLink&fasttrack=False&searchstring=86715K211

Argh, I love McMaster's online catalog, but it's a PITA to link to. Item number: 86715K211.

If you think that will work, I can cut that 12"x12" sheet in half and send it to you...

macona
08-22-2009, 04:00 AM
Just get te Kluber NBU 15. Its only about $35 for a small tube that will last a lifetime. You only fill the bearings about 30%. Use clean solvent and do all this in a clean area.

Although the bearing are most likely shot now that you have taken the spindle apart. Found that out when I rebuilt my surface grinder spindle.

Wether you choose to use the existing bearings or get new ones you need to run the spindle in. Ideally its best with something like a VFD where you can gradually get the spindle up to speed over about an hour. You need to monitor the temp of the bearings. Though I am not sure how fast your workhead runs.

JoeLee
08-23-2009, 09:36 AM
I was told by an engineer at KO that "Lubriplate EMB" (electric motor bearing) grease would be just fine. I cleaned and lubed my surface grinder bearings with it about 10 years ago and they are still holding up well.
You can remove spindle bearings to clean and grease with out doing any harm to them as long as you don't use too much force pressing them out and never ever tap with hammer. Typically bearings of this type are a very light press fit, moderate hand preassure, too tight a press fit would only distort the race and the bearing would loose it's accuracy.
The way I have cleaned these bearing in the past is after a couple passes through the cleaning solvent to get the old grease out I vibrate them gently in alcohol. I have an old vribrator i used for cleaning my brass when I used to reload. I use a clean white container like a cool whip container and let the bearing sit in the alcohol for about 20 min. You would be amazed at the fine particals that sift out after you think the parts washer got them clean. The alcohol dries fast and leaves no residue.
As stated before all this should be done in a very clean area of the shop.

JL.................