8520 bearing replacement

[steamer]

Hi All,    As some of you know, I have a Clausing 8520 vertical mill.    It's a popular mill with the model engine crowd, as it's fairly stiff for its small size, and has lots of features of a Bridgeport without the floor space.   Mine came from a friend of mine, Ray Hasbrouck.    He bought it new in 1964, and owned it till he died.     I have the 1964 bill of sale hanging in my shop. 

In any case, the past 53 years have been busy ones!   Ray built a lot of engines with this mill, and I've certainly used it.

Recently, the countershaft bearings have started to squeal on start up.   Tonight more so...enough that I stopped the mill and started looking into what's going on

The countershaft bearings feel like their full of sand...obviously they're done.    so .....I'll be replacing bearings, probably all of them

I'll post the effort here for the sake of those who are going to need to go through theirs.

Here are the Clausing part numbers, I'll post commercial part numbers once I find cross references for them

[b.lindsey]

With the new bearings it should be good for another 50 years Dave.  Hope the replacement goes smoothly for you.

Bill

[steamer]

The spindle doesn't feel "Bad"...but it's got just as many miles as the countershaft....I have the bottom angular contact bearings already.   but I'm probably going to go through all of it..

It got a new motor when I bought it, and I repaired a bunch of things on it when It got installed.   

Dave

[steamer]

Spindle Bearings

[steamer]

Countershaft bearings...from

http://www.wentztech.com/metalworking/equipment/clausing-8520-mill/

[steamer]

Spindle Bearings

Went to my local bearing supplier this morning, and he had everything I needed
Driven Pulley  Bearings    (2) FAG   6005-2Zr-C3-L38

Top Spindle Bearing     (1) FAG 6304-2Zr-C3-L38

Upper Idler Pulley Bearing    (1) FAG 6201-2ZR-C3-L38

Lower Idler Pulley Bearing    (1) FAG 6202-2ZR-C3-L38

And the seal.   Listed as a CR  13548   Cross referenced to a Timken  472354

I need to pick up some snap ring pliers....then I can get at to it.

All in,  including the Fafner 7205WN-SU angular contact bearings, your spending about $200.00 in bearings.

Dave

[steamer]

The countershaft bearings took 15 minutes.   1 roll pin and they came apart.

BIG improvement!....

Dave

[Vixen]

Dave,

I just looked up those bearing part numbers because some of the numbers sounded familiar.

They are all metric bearings, Is it (was it) normal for American built machines of fifty years ago to be made with metric bearings? Also is it normal for your bearing suppliers to hold metric bearings in stock?

The motor bearings on my Austrian built Emco Mill have started to rumble after 30 years of hard work so I, like you, am in the process of replacing milling machine bearings.

Mike

[steamer]

Yes on all counts.    The standardization to metric happened a long time ago.   I'd be more concerned if they were all English!!!

Like I said the countershaft was all of 15-20 minutes, and is now much better.    The spindle feels good........and that is attractive...but I do have the bearings.

Hmmmmmm

Dave

[steamer]

I was actually more concerned about the spindle seal!   that is an English size.  He had a cross referenced Timken though.

I know it will come apart pretty easy too.......

Dave

[steamer]

Picked up a set of snap wring pliers and a bearing puller.  I also got some suitable grease.    Spindle top end is about 3250 rpm.   Runs pretty quiet at that speed right now.

I'll get it all together complete before I pull the trigger.   I need to clean the shop too before I tear open the spindle.   I may have some time off coming shortly....if I do I'll do it then

Dave

[Bobsmodels]

Hi

I did a rebuild of an 8520 about 12 years ago.  I followed mostly the writup in the Clausing site:

https://groups.yahoo.com/neo/groups/clausing_lathe_and_mill/files/Clausing%20Mills/Vertical%20mills/

One is called Fred’s 8520 restoration and the other  85xx hd rbld.   Both have lots of good information on rebuilding and disassembly.

One recommendation is to get a new seal for the bottom of the spindle, I got mine from Clausing.

As for the bearings I would advise doing some homework on the spindle bearings ie the 7205WN-SU.  Make sure you are getting what you want in terms of quality.  I originally got a set of bearings not really knowing anything about them and they were ABEC-1, sure was a good price.  I see them on ebay at 47.99 each.  I ended up putting in a set of ABEC-3.   I was told by an experienced spindle repair person that the ABEC-3 were considered very good skate quality.  He strongly recommended at a minimum ABEC-5 matched ie a pair tied together and matched.

I sold the 8520 a month after finishing it having stumbled on a modeler used only 8530 for sale.  The fellow that purchased the 8520 has made many models with it and has had no issues with the ABEC-3 bearings.

While you are at it replace all of them, table included.  You have the machine down so have at it.  If nothing else replace the top spindle bearing, and the bearings in the large pulley on top of the spindle.

The bearings in my 8530 are from 1979, 47 years old.  They are still running smooth so I am not going to touch them for now.

Have fun

Bob

[steamer]

The angular contact bearings I picked up are ABEC 3's  ABEC 3 is sufficient for this Mill.     I'll be changing all the head bearings.    I want to wait till I know I have enough time to do it right, and the shop is cleaned up a bit.

Dave

[jschoenly]

Good info!  I haven't had time to put my friend George Luhr's Clausing mill back in service, but plan to soon.  I'll be keeping this stuff for reference just in case.  George kept stuff in good shape, but he also had a lot of miles on his machines!