# Replacement For Logan Headstock Double Row Bearing



## James_Douglas

After weeks of research and a dozen conversations with bearing manufacturers I came up to a brick wall on finding a "correct" bearing for the Logan Lathes.  There are several bearings that will in fact fit dimension wise, however the key design parameter is the fact that the original bearings had a preload in them.

The manufacturers all make a single row bearing with a preload, but no double row bearings.

I called Logan lathe and talked with Scott Logan before ordering his bearing.  Since Logan Actuator sells the bearings, at a much higher costs than the other dimensionally same bearings, I wanted to know which of the 3 or 4 preloads that are generally available by the manufacturers he was using.  I was interested in going up on step if possible.  Since the bearing is a special order non-refundable item I wanted to know if there was any choice.

Scott would not discuss in detail the bearing.  All he would say was that the bearing met the original specifications.

Below is an email I sent to Logan Actuator yesterday in the morning.  I am waiting on an answer.

--------------------------------------Original Message---------------------------------------------------

From: James Douglas

Sent: Monday, April 13, 2015 10:35

To: 'Logan Actuator Co.'

Subject: Question on Logan 820 bearing

ATTN: Scott Logan,

Hello Scott,

I don't want to beat a dead horse. However, I was suspired when I opened the box with the bearings inside. They are SKF. Prior to talking with you on the telephone and prior to ordering the bearing from you, I had talked with SKF and a lot of other bearing manufacturers. They all told me the same thing. They did not make any double row bearings with a built in preload.

I assumed that you were having the bearings made by a specialty house with a preload just as the original 5000 series New Departure bearings that Logan used in the 820 lathe (see attached).

I emailed and talked with SKF engineering this morning. I read them off the part number on the box and the part number off the bearing. Their response was:

****************************************************

SKF 3208 A-2Z is by design a bearing that has internal clearance. This bearing has axial internal clearance equal to 0.0004/0.0011 in. which is considered in the "normal clearance" range. Other identifiers in the part number to specify internal clearance are:

C2: axial internal clearance smaller than normal

C3: axial internal clearance greater than normal

C4: axial internal clearance greater than C3

Again, this bearing cannot be preloaded as manufactured.

*****************************************************

There is no marking on the box or the bearing to indicate that it is anything other than a what SKF calls a "normal clearance range". Also, they stressed that clearance range and preload are not the same things and I was told not to confuse the two. They also made it clear that this bearing "cannot be preloaded as manufactured".

Since the preload is what makes the lathe shaft not walk forward or back and there is no provision to set any preload on the shaft (by design) then the bearing needs to have a preload.

Can you shed any light on this for me please? If the bearing was drop shipped, is it possible that I did not get the correct bearing?

Thank you for your time.

James.
------------------------------------------------------------------------------------------------------------------

If anyone can shed any light on the bearing issues I would be grateful.

It appears that what I got from Logan was a "tighter" bearing than the other generally available bearings of the same size, but still without a preload of any kind.  If you see the attachment, which is a page from a New Departure catalog 19th edition 1948, all 5000 series bearings had a preload.  The Logan 45508 bearing is a 5000 series ND bearing. The 4 in the number just denotes a snap ring.

I am starting to get somewhat upset with the fact that I did my homework, talked (or tried) with Scott Logan about the bearing and its issues, spent the money for his part numbers and then got a bearing that the manufacturer tells me has no preload which by definition does not equate the original specifications.

When I get a response I will let people know.  And again, if anyone has any insights, I am all ears.

James


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## mjhenks

Not alot of detail to add but i can say that i ended up at the same place.

At work i deal all sorts of custom bearings made special for our machines.  Mostly linear but also thin section.  I have dealt with all of the big players and local distributors.  In the end, i was satisfied that whatever Scott was selling, while made by the big players was made special for the Logan to match the old spec.

My Logan 400 origianally had New Departure Bearings.  I happen to have a catalog from back in the day and if i recall was able to cross the bearing i remove with the specification but of course New Departure is long gone as no-one makes the same thing anymore.  I even tracked down NOS New Departure bearings.  I was able to find the rear bearing but not the front.

In the end i realized it was a dead end unless i wanted to go out on my own.  i ponnied up for what Scott sells and have been very happy.  (I was also VERY careful when installing them...)

I am pretty sure i have more info in my Logan 400 headstock rebuild thread.

Matthew H


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## James_Douglas

Thanks for the input Matthew.  I also am at a dead end and will have for the time being to use the bearing that Scott sent.

The SKF engineers did in fact look up the dimensionally identical MRC bearing they sell and it has more clearance than the SKF I got from Scott.  So, the one Scott sells is "better" than most of the other dimensionally identical bearings to the ND bearing.

That said, I plan on using my lathe, in addition to other things, to make some number 14NF screws for my 1940's Desoto's.  Chrysler corp used #14 and #16 screws in the body that things like the dash bolt into.  All in body welded or caged nuts.  Since the local and mail order houses don't have them anymore...

That is one reason when I am interested in the least movement on the spindle I can reasonably get.

I did talk with the folks at NSK Bearing.  They have a spindle bearing with a choice of four different pre-loads to choose from.  I found one that has the same ID as the New Departure (ND) bearing.  As a set of two it is within 0.5MM in length.  The problem is the OD is smaller.

An NSK engineer said that I could make a sleeve out of billet steel...that was on the exact low side of allowable ID...that I could press the two bearings into this new collar.  If the collar had the snap ring in it the sleeve would float (expand dur to heat) against the cast iron on the headstock like the original outer race.

I think what I am going to do is use the bearing supplied by Scott Logan for now and hit ebay looking for another spindle.  I will them make up a sleeve and get the NSK spindle bearings and then swap them out down the line.  Of course taking measurements both before and after to see what I get.

One thing the engineers told me.  That since this is a hobby lathe that I can use more preload to get a much tighter spindle. The life of the bearing would be 1/2, but using it at home and not in production it would still out live me.

James.


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## hvontres

James,
Are there any special markings on the bearing races? That might indicate a custom version of the stock SKF bearing.


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## James_Douglas

hvontres said:


> James,
> Are there any special markings on the bearing races? That might indicate a custom version of the stock SKF bearing.



Hi, there is nothing on the races but the usual numbers.  I asked the SKF engineer if one could special order a double row bearing with a preload.  Their response was that you could not in anything but very large quantities.  They do not do small order specials and have not for a long time.  Also, the type of bearing in question they said was manufactured in such a way that would preclude doing a preload.

Now it is possible that the two different SKF personnel I talked with are wrong. But, I doubt it.

I am interested in hearing back from Scott Logan on this.  So far, over 24 hours and nothing in reply. Not even a note to say they are looking into it.

When I asked him in our phone conversation some weeks back about if I could special order a larger preload he would not even talk about it.  He just said the bearing he sells is the same as the original specification.  I am starting to wonder if the reason he did not want to talk about it is because the bearing does not have any preload.

If the bearing does not have any preload then although it may function, it is not as I was told a bearing that met all the original bearing design specifications. The New Departure bearings all had preload and unless Logan or SKF can demonstrate to the contrary...the shipped bearing I have does not meet those original specifications. 

What irritates me is the lack of transparency on the whole thing.  If the shipped bearing is the best that can be done without re-engineering the headstock, then so be it.  But be upfront about it and publish the original specifications and the specifications of the replacement bearing and acknowledge the differences.  The someone can make an informed decision if they want to investigate re-engineering the bearing solution or not.

James.


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## wa5cab

I have no experience with lathes with ball type spindle bearings.  But I will point out that one way to introduce preload  on the bearings would be to place an inner race shim on one end of the spindle or the other, in the desired thickness.  This would be much cheaper than modifying the headstock.


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## James_Douglas

wa5cab said:


> I have no experience with lathes with ball type spindle bearings.  But I will point out that one way to introduce preload  on the bearings would be to place an inner race shim on one end of the spindle or the other, in the desired thickness.  This would be much cheaper than modifying the headstock.



Unfortunately, the design of the headstock makes using shims a moot point.  One person used a Belleview washer to ad a preload, however, the SKF guys told me to be careful using an external preload with this bearing due to its internal design. 

JD.

PS.  Still not reply to my inquiry to Scott Logan.


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## wa5cab

Besides the fact that Belleville washers aren't suitable for setting spindle endfloat on a lathe, if you can install one of them such that it reduces the end float with no thrust applied, then I don't understand why an inner race shim of the proper thickness wouldn't do the same thing plus not be sensitive to thrust in one direction.  But I don't have a headstock or headstock cross-section drawing to look at.


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## Jdeking1959

So has the dog caught it's tail yet? I have a friend who works at SKF and I will just take my bearings over to him and figure out a replacement.
When I find out the proper workable replacement I will sell all of you the information $1,000,000.00.  I'm thinking a cone roller bearing will
do the trick instead of a preload.


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## expressline99

It's interesting how many iterations of this bearing topic on these lathes I've seen. I'm not sure I have ever seen any other easy answer aside from buying Scott's bearings.  Thankfully I haven't had to do mine yet. But if I had to I'd probably go with his.


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## RonRock

Well now I am in the same boat. I am midway through a referb of my 1937. I'll come right out and say that I know very little about bearings. I figured I'd get the numbers off the OEM's that I pull and find replacements that match. It seems that is not the best option. 

Is reusing the old ones a realistic option? How would I clean them for reuse?

Any advice on replacements?


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## Richard White (richardsrelics)

Well, cleaning them is easy.... I went to Walmart, bought a turkey baster, that is the syringe thingy you baste your turkey with, also bought one of those metal drain screens.  Seen here:  https://www.walmart.com/ip/4.4-Diam...iner-Basin-Filter-Mesh-Sink-Strainer/45594267.

I placed the bearing in the strainer over a container that will catch fluids, then used the baster to use Kerosene to pour onto the bearing that way as the Kerosene runs thru the bearing it will dissolve the old grease.  This process takes a while but you should notice a difference, now if you have a pump that can pump flammable fluids then instead of the baster you can use it to get a constant flo.  DO NOT reuse the used Kerosene and run it thru again....putting the grit and crud back in is kinda silly.

Also would not recommend using a parts washer for the same reason.... dirty fluids are not your friend here.

Hope this helps

Richard


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## RonRock

Thanks Richard. I'm sure that would be a good way to clean unsealed bearings, have done it many times. But these are sealed bearings.

I should ask what price is everyone getting from Logan? I don't see much in actual prices paid. Maybe this is actually a moot point, if they aren't going to be way out of range. I did see someone mention that he couldn't see spending $1000.00 for the Logan replacements! That got my attention, I can't spend that kind of money on this either. But if the price is within reason.


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## Nogoingback

I replaced the bearings in my Model 200 headstock with Logan sourced bearings recently.  The double row was $211.25.  The other one, which can be purchased
from a bearing supply, was $30.75.

The old double row was sealed on one side with a metal shield, and open on the other.  It
was a New Departure with the original Logan p/n on it.


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## expressline99

Well I ran into a set of NOS new departure bearings that appear to be correct for my Logan 200. The only difference I can see in the set is the missing slot for the snap ring. I should be able to turn one into it. I manage to pay $68.00 shipped so maybe they will fit. 

Paul


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## Holescreek

The beauty of Logan lathes is that aside from dedicated castings everything to repair them can be bought off the shelf.  Sounds like there is some "special sauce" (or just MAGIC!) in the higher priced but identically marked bearings.


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## expressline99

Holescreek said:


> The beauty of Logan lathes is that aside from dedicated castings everything to repair them can be bought off the shelf.  Sounds like there is some "special sauce" (or just MAGIC!) in the higher priced but identically marked bearings.



I'm certainly interested to see if these fit. If so it will be the first time I've seen the same bearing anywhere else. I will report back when I know for sure with bearing numbers. If they don't work then I will crawl away from this thread.  After reporting that they don't work...with numbers. 

Paul


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## expressline99

Well I got the bearings installed and they fit just fine. I found NOS new departure bearings.  One difference was that mine didn't have the groove for the snap ring. That wasn't too horrible. Except the casings on the bearings are quite hard. Don't expect to cut the groove with HSS I quickly burned up a tool tip trying. Which was OK because I had a carbide backup. That cut it just fine.

So for the double row. The new departure numbers on the box: 45507(MAX).ND  and  W0140457

For the single row: The New departure numbers on the box: 77506.ND  and  W0140461

It quieted my head stock down a bunch. I was really impressed.  And I only paid $68.00 including shipping. What a deal.

Paul


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## Holescreek

Any change in spindle runout?


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## expressline99

Holescreek said:


> Any change in spindle runout?



Unfortunately, I didn't test the spindle before pulling it. However, I did check right at the spindle behind the threads and it's maybe .0005? Might be less it's almost impossible to tell. Not a lot of movement between the 0 and the 1st thousandth on the dial. I was so excited to get a deal on the bearings I jumped at it. The ones I had apparently were more noisy than I had previously thought. Now 80% of the noise is from the gear rack when engaged. I'll have to check it again tomorrow just for kicks.

Paul


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## Richard White (richardsrelics)

Yeah mine has substantial gear rack noise when engaged, but hey this is good old fashioned antiquey machinery here, we don't care about noise pollution!


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## E Ragnar

Like others I decided to replace the 70+ year old v-belt drive on the spindle of my *Logan 400 *Lathe. This would give me the opportunity to clean the various parts and inspect the bearings. I will not go into detail of how to disassemble the head stock because it is covered in other forums. What I discovered is the spindle bearings are metric and this gave me a mild surprise! The bearings were stiff and rough because the grease had turned to a hard wax consistency. I decided to replace the bearings using the metric dimensions and found there are many to choose from. The main bearing (ref 0674) has a 40mm bore, outer diameter of 68mm, and a thickness of 15mm. The main bearing also has a snap ring which is an option from several manufactures. The back bearing (ref 0675) has a bore of 35mm, outer diameter of 62mm and a thickness of 14mm. I used a local bearing supplier "Motion Industries" to purchase new bearings manufactured by SKF. Main bearing SKF 6008 2ZNRJEM, rear bearing SKF 6007 2ZJEM. Decode the SKF part number, 600x = 6000 series bearing, x is bore times 5 ( ie, 6008, 8x5 = 40mm bore, 2Z = 2 shields, NR = snapring, JEM is type of lubricant). The lathe runs very smooth and quiet with no wobble in the spindle as best as I can measure.


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## Oldvetteman

E Ragnar said:


> Like others I decided to replace the 70+ year old v-belt drive on the spindle of my *Logan 400 *Lathe. This would give me the opportunity to clean the various parts and inspect the bearings. I will not go into detail of how to disassemble the head stock because it is covered in other forums. What I discovered is the spindle bearings are metric and this gave me a mild surprise! The bearings were stiff and rough because the grease had turned to a hard wax consistency. I decided to replace the bearings using the metric dimensions and found there are many to choose from. The main bearing (ref 0674) has a 40mm bore, outer diameter of 68mm, and a thickness of 15mm. The main bearing also has a snap ring which is an option from several manufactures. The back bearing (ref 0675) has a bore of 35mm, outer diameter of 62mm and a thickness of 14mm. I used a local bearing supplier "Motion Industries" to purchase new bearings manufactured by SKF. Main bearing SKF 6008 2ZNRJEM, rear bearing SKF 6007 2ZJEM. Decode the SKF part number, 600x = 6000 series bearing, x is bore times 5 ( ie, 6008, 8x5 = 40mm bore, 2Z = 2 shields, NR = snapring, JEM is type of lubricant). The lathe runs very smooth and quiet with no wobble in the spindle as best as I can measure.


Just wondering how your SKF 6008 2ZNRJEM bearing is holding up to use.


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## E Ragnar

Oldvetteman said:


> Just wondering how your SKF 6008 2ZNRJEM bearing is holding up to use.


The bearing SKF 6008 2ZNRJEM is working fine with no issues. The country of manufacture is (if I remember correctly) Argentina. I might add, that the lathe is not used very often. The bearings out of the box had extremely smooth feel while turning the internal ring manually with no indications of roughness - smooth as silk. The lathe with the new bearings is noticeably quieter in operation.


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## Oldvetteman

E Ragnar said:


> The bearing SKF 6008 2ZNRJEM is working fine with no issues. The country of manufacture is (if I remember correctly) Argentina. I might add, that the lathe is not used very often. The bearings out of the box had extremely smooth feel while turning the internal ring manually with no indications of roughness - smooth as silk. The lathe with the new bearings is noticeably quieter in operation.


Thanks for your response.  I should have asked in my previous post, but have you ever measured the radial play in the bearing?


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## E Ragnar

I did use my indicator gauge on the spindle. My gauge has 0.001 inch divisions. The gauge shows some very small movement, much much less than 0.001 inch - that is the best I can measure and I would estimate several 1/10,000 of an inch. BTW, the SKF 6008 is an ABEC 3 bearing which then implies the balls in the bearing are ground within;  *ABEC 3*: 0.0050 mm (0.000197 inches)


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## Beckerkumm

SKF JEM bearings are generally C3 clearance which is seldom used in a spindle bearing unless running at the bearing's maximum speed limit or in a hot environment like electric motors.  Yours seem to be running with low runout but a CN or even C2 SKF Explorer ( ABEC 3 ) would be my choice.  The higher the precision the lower the clearance that you can tolerate which is the key to tight runout.  Dave


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## E Ragnar

It all comes down to cost and availability. The SKF 6008 2ZNRJEM was a comparable replacement to the original bearing that was no longer available for the Logan 400.


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## expressline99

Years later and mine are still running great!


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