# Countershaft very HOT.



## ThunderDog (May 23, 2017)

Let me put as much info as I can to solve what should be a simple problem.

Atlas MFB
Cutting mild steel
Using 1/2" end mill (because I don't have the original arbor...yet.)
Each pass I raise the knee (Y axis, correct?) to a depth of cut set for .010" - .015" and my Z axis(parallel direction to the spindle) is always set to .125" cut.
Tried all of the various back gear speeds (160? rpm(can't recall the setting at the moment) and 440 rpm)
Tried table feed set at .006" and .003"
I've adjusted the countershaft screws for the pulleys to the point just beyond where the belt will slip as I don't want to burn up the belt.  The problem then is that I can't take but the tiniest of cuts without the belt actually slipping.  So, I tried tightening the belt so I can actually take a cut.  But then the countershaft bearing heats up real hot, like 150º hot measured with a infrared laser thermometer. 
I checked the alignment of the countershaft pulley in relationship with the spindle pulley using a straight piece of square stock and it checked out fine.  Of course, the heat is being transferred through the pulley to the spindle which measured much cooler but still hot for my liking.  90º on the spindle pulley.
Everything is oiled with Mobil Velocite #6 spindle oil.

My thoughts, just buy a new belt after work to eliminate that variable.  I'm probably overthinking all of this, right?
This all got me thinking, what's the average depth of cut that one can expect from this machine using an end mill.  I know that question has alot of variables like material being cut, type of cutter, etc.  Just trying to learn this new to me machine.

Pic of what I'm talking about for clarity.  The front pulley/bearing are the hot spot.


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## Us Navy machinist (May 23, 2017)

I know you said that you checked the alignment with a bar, but is it possible that it is seizing within its journals? When is the last time you cleaned out the oil port holes?


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## Rustrp (May 23, 2017)

What I'm seeing looks like grease on the end of the shaft, not oil? How often do you add oil or need to add oil?


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## Dave Paine (May 23, 2017)

I think you answered your own question.  I would try a fixed length belt.   I have link belts on a couple of woodworking machines, a jointer and drum sander.  Both work well.   If the belt is slipping I would try a different belt.  I liked the cogged V belts even with normal pulleys since they flex easier on the smaller diameter pulleys.

I am not surprised the tight belt is causing heat.  A lot of friction with a tight belt on the solid bearing shaft.  If these were roller or ball bearing, they could likely take the pressure without heating up.


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## ThunderDog (May 23, 2017)

I completely disassembled and cleaned this machine and have only ever used oil.  The oil ports were cleaned and cleared. Didn't they originally have some type of filter material in the oil ports to keep dirt out? Mine never had anything inside of them.  

Rustrp, I thought the same thing when I started using the machine. 
I was thinking, "Wow that's spewing dirty oil already? Here, let me wipe that off with my finger(machine was off, of course).  WOAH, that's hot!!"  And then the investigation began...

I'll change the belt and post my findings later this evening.


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## woodchucker (May 23, 2017)

ThunderDog said:


> I completely disassembled and cleaned this machine and have only ever used oil.  The oil ports were cleaned and cleared. Didn't they originally have some type of filter material in the oil ports to keep dirt out? Mine never had anything inside of them.
> 
> Rustrp, I thought the same thing when I started using the machine.
> I was thinking, "Wow that's spewing dirty oil already? Here, let me wipe that off with my finger(machine was off, of course).  WOAH, that's hot!!"  And then the investigation began...
> ...


Not filter material, but felt. The felt holds the oil so it gets a steady stream of oil. It wicks it down. That might be your problem, you might be slinging it out w/o a felt.  You are relying on only whats there at the moment, there's no constant delivery system.


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## ThunderDog (May 23, 2017)

10-4.  I'll definitely add that.


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## woodchucker (May 23, 2017)

ThunderDog said:


> 10-4.  I'll definitely add that.


Generally there are 2 ways that felts are installed. One there is a key way cut in the bearing. The felt fits in there and wicks the whole bearing length. The other is that the feed tube will have a felt installed that will hold the oil and contact the journal. That's for smaller journals. Larger use the keyway. At least from the couple of machines that I have rebuilt .
Others may have more info.  See if you can get a diagram of your assembly and see how and if felts were used. If you don't have oillite bearings, chances are they need felt.


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## Silverbullet (May 23, 2017)

By looking at your pulleys there either worn badly or the belt needs to be wider 5/8" instead of 1/2". The red belt is riding way to low in the pulley . The flat of the belt should be level or a tiny bit above the pulley. Just my observation of the set up.


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## Rustrp (May 23, 2017)

I think we can put a lot of emphasis on the belts but if the belts were at issue it would be the pulley that's hot, not the end of the shaft, although you did say front pulley/shaft. If it were the belt, that's a lot of heat transfer to get the shaft hot to the touch and if so the belt should be close to smoking. Based on your comments it does seem to be a lubrication issue. I'll ask something that you've probably already checked, but with the belts off, does the shaft turn freely?


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## David S (May 23, 2017)

Silverbullet said:


> By looking at your pulleys there either worn badly or the belt needs to be wider 5/8" instead of 1/2". The red belt is riding way to low in the pulley . The flat of the belt should be level or a tiny bit above the pulley. Just my observation of the set up.



Good observation.  I wonder if the belt is riding on the bottom of belt rather than the sides?  And hence the need for way too much belt tension.

David


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## Silverbullet (May 23, 2017)

Rustrp said:


> I think we can put a lot of emphasis on the belts but if the belts were at issue it would be the pulley that's hot, not the end of the shaft, although you did say front pulley/shaft. If it were the belt, that's a lot of heat transfer to get the shaft hot to the touch and if so the belt should be close to smoking. Based on your comments it does seem to be a lubrication issue. I'll ask something that you've probably already checked, but with the belts off, does the shaft turn freely?


I think you'll find with the belt slippage he's tightening the lever causing savere pressure on bronze bearings , there's the reason the shaft gets hotter then the pulley does . It's part of the cause and affect . With as wet as the shaft is it's oiled or greased.


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## VSAncona (May 23, 2017)

I agree with Silverbullet. A 1/2" belt is too narrow. The original was closer to 5/8" wide. Clausing recommended a Gates 3280 to me for my mill.


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## Rustrp (May 23, 2017)

Silverbullet said:


> I think you'll find with the belt slippage he's tightening the lever causing savere pressure on bronze bearings , there's the reason the shaft gets hotter then the pulley does . It's part of the cause and affect . With as wet as the shaft is it's oiled or greased.


 
If the shaft was wet, as in wet...wet...wet, we would see a drop or drip, it's what #6 does. This is an adjustable link type belt and the difference of 1/8" in width doesn't change the dimensions on the side "Vee" enough that would cause the slippage or heat buildup. In regards to the position the belt is sitting in the pulley groove, we could imagine where a belt may land in a pulley if this were variable speed, so being another 1/8" higher in the pulley will only change the speed minimally without adding or taking away tractive force or effort. As a rule, a belt and pulley are sized based on the HP of the motor to insure they hold up to the physical demands of startup torque etc. and it isn't emparative for a v-belt to be sized precisely for the machine to work. With that said, I would be just as happy for TD if he says he put a 5/8" belt on and all is cool.


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## VSAncona (May 23, 2017)

The narrow belt is an issue if it's bottoming out in the pulley because it prevents the sidewalls from gripping the pulley the way it should, which would lead to the belt slipping. If you look at the photo TD posted, you can see that the inside of the links are black from rubbing on the bottom of the pulley groove. I'm not saying that's the only possible cause, but it's where I would start.


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## Rustrp (May 23, 2017)

VSAncona said:


> The narrow belt is an issue if it's bottoming out in the pulley because it prevents the sidewalls from gripping the pulley the way it should, which would lead to the belt slipping. If you look at the photo TD posted, you can see that the inside of the links are black from rubbing on the bottom of the pulley groove. I'm not saying that's the only possible cause, but it's where I would start.


If that were the case, I agree.


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## ThunderDog (May 23, 2017)

Bought a link belt for now.  It's just shy of 5/8" in width.

Before we get to that I have to ask another dumb question.  Do the oilite bearings have a hole to allow oil direct contact with the shaft on this thing?  The oilites are impregnated with oil, right? Is that all they required, oil contact on the outside? Doesn't seem right to me.  See photos below, no hole in the bearing. Paper towel for clarity. BTW, do you like the cooked and heavily scored shaft?


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## Rustrp (May 23, 2017)

ThunderDog said:


> Bought a link belt for now.  It's just shy of 5/8" in width.
> 
> Before we get to that I have to ask another dumb question.  Do the oilite bearings have a hole to allow oil direct contact with the shaft on this thing?  The oilites are impregnated with oil, right? Is that all they required, oil contact on the outside? Doesn't seem right to me.  See photos below, no hole in the bearing. Paper towel for clarity. BTW, do you like the cooked and heavily scored shaft?
> View attachment 234162
> ...



I think you just eliminated the belt as a problem. Yes, the oil needs a path to the shaft.

Edit; However dumb you may think the questions may be, you're getting smarter by the minute.


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## ThunderDog (May 23, 2017)

I made the cooked shaft all by my little self and learned about Oilite bearings today during play time.

I will go out on a limb and assume these were not the original bearings.  The previous owner must have had a blast hacking this machine. Between the welded overarm, adding an additional set screw to the spindle pulley (different topic/different thread), etc.  The list goes on.


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## Rustrp (May 23, 2017)

ThunderDog said:


> I made the cooked shaft all by my little self and learned about Oilite bearings today during play time.
> 
> I will go out on a limb and assume these were not the original bearings.  The previous owner must have had a blast hacking this machine. Between the welded overarm, adding an additional set screw to the spindle pulley (different topic/different thread), etc.  The list goes on.



Are the bearings/bushings oilite? Maybe just bronze bushings? Oilite bearings do dry out but I have used some (I forget what it is called) that have grooves machined in them along with holes located in the grooves. I have used both having spiral grooves and straight grooves in the bearings. Oilite is suppose to be self lubricating but.......?


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## markba633csi (May 24, 2017)

I don't think the link belts will transfer all the power the machine is capable of compared to a standard v belt.  I've heard the link type can wear the pulleys faster too. 
Mark S.


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## wa5cab (May 24, 2017)

Oilite bushings do not require an oil hole because the material itself is porous.  That being said, if the bushings were changed by the PO whom you mentioned, they may not be Oilite.

The original belt on the MFB and MFC was a 5L280.  I would install that as soon as you have time to pull the spindle and back gears to do so.  I expect that the 1/2" link belt was slipping.  However, if the pulley wasn't getting hotter than the bearing, that wasn't directly your major problem.  But if it was and you tightened the belt to make up for it, you were probably putting too much side load on the bushing, causing it to overheat.

On your other question, I wish that you had included a photo of the workpiece mounted in the mill.  Are you cutting on the back side with the end of the milling cutter or on the top with the side?  If the former, you should be cutting with about 85% of the 1/2" diameter, not 2% or 3% of it.  And technically your DOC is 1/8".  I have done a lot of whittling with the milling attachment on my 3996 (because my MFA isn't running yet), and I usually use 85 to 90% of the diameter of a 5/8" or 3/4" end mill, with a DOC of 0.010" to 0.020" in mild steel or 0.050" to 0.100" in aluminum.


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## ThunderDog (May 24, 2017)

wa5cab, the bearing was the hottest point of contact.  I still have the job clamped on the table, but for now while I'm at work here is a little diagram:



 Thank you for the info. regarding the DOC.  To clarify, you're saying that with end mills the amount of "side" contact of the cutter is DOC?  I was using the DOC term as the amount that the knee was raised to cut a depth of .010"- .015".

Lots to learn, regardless it's a TON OF FUN!!


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## f350ca (May 24, 2017)

I tried link belts on my table saw, it uses a short pair between the 3 hp motor and the arbour. I couldn't get them tight enough to not slip on all but the lightest cut. Replaced them with regular V belts and the saw was back to normal. On light loads they're probably ok but they wouldn't carry the load of the saw, but they did seem to run a little quieter.

Greg


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## Rustrp (May 24, 2017)

wa5cab said:


> Oilite bushings do not require an oil hole because the material itself is porous. That being said, if the bushings were changed by the PO whom you mentioned, they may not be Oilite.


So this begs the question; Why bother with inserting any device that allows the operator to add oil to the bearing......or insert lubrication instructions in the owners manual. The service requirements of the machine in question would dictate bearing design. It's possible the bearings were changed out and it's also possible that the oil had dried up. 

Oilite is designed to be self oiling but the oil does dry out. In essence they are designed to be a spounge, a hard metal composite pressed into a specific shape and size and usually only bored to size if absolutely necessary because doing so plugs the cells which move oil. Most devices that use oilite have some means of lubrication based on service, whereas oil would be added once a year, etc.

I'm being redundant here but I suppose in part it's due to the push toward the belt being the cause of the heat buildup.


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## Rustrp (May 24, 2017)

wa5cab said:


> Oilite bushings do not require an oil hole because the material itself is porous.



Robert,

My response wasn't intended to negate and there's nothing in the parts diagram that indicates a hole exists or needs to exist. My response was half--azzzzed so my apology to you. 



Rustrp said:


> So this begs the question; Why bother with inserting any device that allows the operator to add oil to the bearing......or insert lubrication instructions in the owners manual.



My guess is the bearings were plugged full of gunk due to age and no oil could or would flow. It's possible the bearings were changed out with something other than oilite. This is a good educational opportunity for anyone restoring old machinery. Restoring an oilite bearing can be done but purchasing a new one is probably the best choice. The linked belt as a factor in this was probably #3 down the line in the troubleshooting flowchart.  -Russ


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## bss1 (May 24, 2017)

I have used link belts on a half dozen different machines. These include milling machines, lathes, and several bandsaws. 

With the proper width and profile of belt for the application, I have never felt like they were more prone to slippage than a regular v belt nor do they seem to require more pressure to work.  In my opinion, link belts seems to hook up so well that I wouldn't recommend them for applications where you need some slippage for safety purposes if something were to get in a bind. 

It should be noted that none of my machines are used on a professional or on going daily use, but I have not observed any unusual wear on the pulleys as a result of using link belts.  YMMV

The Fenner Drive link belts come in varying widths and profiles. Make sure you have the right one. If the belt is slipping or requires too much tension, it is likely the wrong size belt.  Is there any oil or grease getting on the pulleys? If so, that can add to the slippage issue as well. 

As the others have stated, the slippage problem may be attributable to the wrong size of belt. Get the right size and profile of belt whether it be a Link or regular v belt to eliminate that as a factor. 

The heat buildup is likely  due over tension of the belt and lack of lubrication. If you pulled the shaft as shown in your pic and there was not a film of oil on it, then it is going to run hot. Regardless, a bearing of this type is going to run somewhat hot due to all of the friction.  You mentioned the right bearing is running at 150 degrees. Did you shoot the temp on the left bearing?   Anyone know what the normal temp should be for a bearing like this?

Speed can also contribute to heat. Does it get as hot if you run with the belt in another pulley position?


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## ThunderDog (May 24, 2017)

Can't say it enough, this forum has good input from everyone and it is very beneficial for beginners like myself.

BSS1, from memory I know the bearing in the back was much cooler.  I just can't recall the exact temp.  With that information I did check to see if both tension screws/pins(M1-271, see pic above) were set with equal pressure.

Short of just doing a simple Google search, anybody have a good source that they have used to acquire some Oilite bearings?


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## bss1 (May 24, 2017)

Try McMaster Carr.


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## woodchucker (May 24, 2017)

I run link belts w/o a problem on many machines, WW and metal working. I agree the right size would be important for slippage.
I looked at your paper towel and shaft. My opinion is that there is not enough oil on either. An oillite bearing would not have a hole in it. There could be a hole to it, but not a hole in it. The hole to it would be to maintain the oil level in the oillite bearing.
Since you have a hole in the bearing, I would say it was replaced by a non-oilite bearing.  if so, you have 2 options. One is to try a felt wick to keep the oil flowing. You will have to oil daily (meaning 8 hours of use). Or replace the current bearing with an oillite bearing. You will still have to oil it, just very occasionally, like maybe once a month. you should have a cap on that oil hole, both wick and oilite will not prevent contamination .. light slurry or grinding dust will work it's way in and down. Order a gits cap from McMaster to keep it clean, or see the caps created by someone here using spent ammo shells (pretty cool). Any way you cap it is fine, as long as you can service it.
My thought is your bearing is a major part of the problem. But like all opinions, it's just an opinion.
I hope you realize that all of what is said by everyone is trying to help, and you are the guy at the helm. We don't get to see everything you do.. so we offer what we feel is the best info we have.
Oillite bearings are sold by McMaster Carr.


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## Rustrp (May 24, 2017)

ThunderDog said:


> Can't say it enough, this forum has good input from everyone and it is very beneficial for beginners like myself.
> 
> BSS1, from memory I know the bearing in the back was much cooler.  I just can't recall the exact temp.  With that information I did check to see if both tension screws/pins(M1-271, see pic above) were set with equal pressure.
> 
> Short of just doing a simple Google search, anybody have a good source that they have used to acquire some Oilite bearings?



As has already been stated, McMaster Carr is a good source or try any industrial bearing supply house in your area.

As you stated, there's a lot of good information here, and opinion based on our experiences. Oilite bearing come in many different shapes sizes and configurations. 

https://www.oilite.com/PDFs/castBronze_designData.pdf


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## markba633csi (May 24, 2017)

To clarify; an Oilite bearing has a distinctive look, once you've seen it you'll recognize it- they're made of tiny bronze particles which are sintered (pressed with heat) into a solid shape.  There's also a similar looking product used as a filter for various liquids and gasses.  
Mark S.


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## wa5cab (May 24, 2017)

We know that with new original bearings and proper size V-belts, the Atlas mills ran OK.  AFAIK, you don't know for certain what the bushings in the countershaft hanger are.  So my suggestion would be to replace the bushings and the belts with OEM parts, and start from a point that we know worked.

On the Depth Of Cut (DOC) issue, I should have said at the beginning that DOC isn't perhaps as well defined for milling cutters as it is for normal lathe tooling.  On a lathe (most of the time), you have a nominally single point tool with not much width in the longitudinal direction.  So DOC is pretty well defined and how large the cutter or insert is doesn't much matter.  So there are only three variables, DOC, Feed, and SFM (related to work RPM and diameter).  With an end mill, face mill, or slabbing mill you have a fourth factor added, which is the width or circumference of the cutter actually engaged with the work. If you are using an end mill (which you are) or a face mill, then I think that most people would call the direction where you show movement of .010 to .015 the DOC.  Which if I understand your sketch would be set by moving the table and work toward the spindle.  And the 1/8" dimension would be table or knee lift.  On a lathe with milling attachment, the .010" to .015" would be carriage traverse and the 1/8" would be milling attachment lift or drop.  If the arrow indicates the direction that the work is moving into the cutter, it is backwards.  With a normal end mill turning in the normal direction, moving the work in the direction shown would be climb milling.  The only movement of the end mill is rotation.   At any rate, with a similar setup on my lathe, I would be using 3/8" or 7/16" instead of 1/8" if the end mill diameter is 1/2".  

Anyway, my guesses as to the cause of the hot bearing is either excessive belt tension in order to prevent belt slippage or no oil getting to the shaft because the bushing isn't porous (solid brass or pores plugged or some of both.


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## Silverbullet (May 24, 2017)

Have you inspected the pulleys , the sides should be flat on the angle on each side . If the pulleys are grooved has I suspect they should be changed also . The sides are where the traction is the v drives the machine. It's a pain to install but the original belt should last for years. I'm pretty sure all these things are causing the trouble. You might be able to do some work on it and install needle bearings with seals and then oiling them the machine will run forever. If mines bad when I get to it I'm going that route , needle bearings and felt or o ring seals on the ends. My atlas is waiting along with several other machines.


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## ThunderDog (Jun 5, 2017)

Thought I would give an update.

Installed the belt as recommended by forum member wa5cab in this thread. That made a DRAMATIC improvement.  Now, I'm beginning to think my other machines in the garage need their link belts swapped. Replaced the bushings with new Oilites from Macmaster.  Also replaced the 5/8 shaft with a piece I had left over from Speedymetals.  It's listed on their site as "stress proof".

For future readers: I had to drill a small hole in both bushings from Mcmaster for oil to make it to the shaft.  I initially ran it without the holes drilled while I setup the alignment. They obviously heated up, so a simple fix of drilling the holes and now both bearings run very cool.  83° vs my original 150° is a major improvement.  Plus, it's so much quieter than before.  I never had a reference as to how quiet the machine should have been.

Thanks to all.


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## woodchucker (Jun 5, 2017)

If they were oillite all you need to do was soak them in oil. No hole. The hole works against you. W/o the hole the oil will fill the bearing and be a source of oil. With a hole it will just travel to the shaft and possibly exit quickly.


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## Rustrp (Jun 5, 2017)

woochucker said:


> If they were oillite all you need to do was soak them in oil. No hole. The hole works against you. W/o the hole the oil will fill the bearing and be a source of oil. With a hole it will just travel to the shaft and possibly exit quickly.


I think as greedy as oilite is, not much oil will escape, especially if TD put new felt in the oil gits to slow the flow.


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## Tozguy (Jun 6, 2017)

TD glad you have solved the hot bearing problem. I had to repair a similar bearing that had run dry and hot. It burnt the felt and residual oil to black. It cleaned up well and I keep a sharper eye on it now. Only question left for me is what is the best oil to use.


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## ThunderDog (Jun 6, 2017)

woochucker,  I totally hear what you're saying.  Thank you for the clarification.

Here's what I did:  (Learn from my rookie mistakes!!)
Simply wiping oil on the exterior and interior of the oilite bearings is NOT the correct procedure.  If you're wondering what oil I'm using it's Mobil Velocite #10.  I use it because it's what I have and I've used it for my lathe spindle.

Here's a link from Mobil for the future readers.


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