Oil or Grease the Needle Bearing on the Drive Wheels

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10 Wheeler Rob
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Oil or Grease the Needle Bearing on the Drive Wheels

Post by 10 Wheeler Rob »

Hey Guys,

Do you guys recomed runing the nedddle bearings on oil or grease? Whats you experence been.

My blue prints show an oil hole in form end of axle to a goove in the axle under the neddle bearing race and the bearing inner race has a hole in. There are no seals in the design.

I have herd of some guys putting a 1/4-28 thread into the end of the axle and screwing in a zert for greasing and then removing zert and pluging the hole with a set screw. There is not clearance to leave the zert in when running.

I see where excess oil would tend to wash some dirt out. I seems to me that punping grease in would tend to push dirt out and make it harder for it to get in. But once dirt gets in gresae it seems to be stuck there for ever.

The engine could have a lot grease all over the inside of the wheels where the excess would come out of the bearing hosuing lsowhen pumping it in also.

So lets see how diverse this subject gets!

Rob
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LivingLegend
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Grease or Oil?

Post by LivingLegend »

10 Wheeler Rob:

I would go with any good quality lithium based bearing grease. If you don't install a dust/dirt seal in the journal box, the grease will act as the seal in the gap between the journal box axle bore and the axle. All you need is around .005 to .010 larger diameter clearance over the axle.... Don't need that large of a gap.

Here's a method I used on a project years ago. I made mini grease fittings (half the size of commercial "Zerk" fittings) that screwed into a hole in the inside (frame) face of the jourmal boxes to just past where the centerline of the bearing width would be. Another hole was drilled from the box bottom intersecting the horizontal hole and up into the housing bearing bore. Then the bottom hole was plugged with about a 3/16" No.5 or No.6 hex head socket set screw, in just enough to where it wouldn't interfere with the lubrication path. I was using drawn cup needle bearings WITH lubrication holes in the OUTER bearing race. The bearings were installed so that their outer race lube hole lined up with the hole in the housing bearing bore. The grease fittings had a small rubber cap on them so that dust wouldn't find it's way into the grease at the open end of the fitting's hole. Made a small grease fitting adaptor for a mini-grease gun. Every time you shot grease into the bearing it flushed out the dust/dirt contaminated grease in the gaps.

Another variation to the above idea is to install the grease fitting ONLY when lubing and then removing it and screwing in a plug to seal it until the next time you need to re-lube.

Regardless, with this method the grease/oil fitting is hidden and you won't have an OVERSIZE out of porportion hole/fitting/screw/plug in the visible face of the axle that sticks out like a sore thumb! Of course, if your bearings don't have a lubrication hole in their outer race you won't be able to use the above idea.

There are all kinds of solutions to your question.... get a few more ideas and decide which one you like best and might want to use!

LivingLegend
Bill Shields

Lube

Post by Bill Shields »

My drive wheels are always done with grease...mostly to keep the dirt out by displacing it outwards at the grease goes in.

Lube fittings are modified SHCS that screw into the center drilled end of the shaft..wipe off the shaft end, remove the screw, pump in a bit of grease and screw the plug back in...neat and clean.

And now, through the modern miracle of the internet, you get a lousy picture of my bad description.
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RET
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Location: Toronto, Canada

Post by RET »

You know, Bill, its amazing how many people come up with close versions of the same idea. What you are describing is exactly what I've done on the Dart chassis that I have. As you may know, Dart (0-4-2) is a Martin Evans design in 7 1/4" gauge & he calls for a drilled hole in the ends of each axle for oil lubrication. That hole meets a cross hole at the center of the axlebox bearing. His idea is to squirt oil in the end hole to lubricate the bearings.

Like you, I also feel that in our locomotives especially, dirt is the biggest thing to guard against & I like the automotive greasing system where the new grease pushes out the old grease & any dirt that is there. For that reason, I've done exactly the same thing you have; tapped the end holes #8-32, used a countersink to put a 60 deg. cone in the end of the axle, modified a standard cap screw so the head has a matching cone & screwed it in to plug the hole for normal operation. When in place, the altered cap screw is almost flush with the end of the shaft.

When I want to grease the bearing, I remove the plug and screw in another #8-32 screw that has been modified so that a standard grease fitting is screwed into the end, grease the bearing & then replace the plug. And here I thought that the idea was original with me! I guess its too good an idea not to have been thought of by many others.

I also put 1" bore needle bearings in the axleboxes. Those bearings are rated for more than 4,000 pounds static load when running on a hardened sleeve, so I guess they should work very well with a 100 pound load running on a plain shaft.

Richard Trounce
10 Wheeler Rob
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RE: Lube

Post by 10 Wheeler Rob »

Thanks fot the input guys.

It looks like grease is the right stuff to use.

You gave me an idea, if i do not like looking at a 1/4-28 hex or flat screw slot slot plug, I could make an adaper to go on the end of the 1/4-28 zert fitting to adapt it down to a #6, #8 or #10 screw size and plug a mcu smaller thresd size.

The idea of the screw slot plug would allow a flush fitting plug that would be hardly noticalble. I will start with the simple hex and go form how it looks in a peice of scrap stock. Now on could alws put tow little holde in it to be drivenin by a spaner wrench also.

But what ever the plug, I would not wnat tit comming out and getting inot the connecting rods, that would be ugly. Any ideas on locking, or am I being over causious. Is my areo space bacground shwoing up here, we never leave anthing not locked. One thought I had was to put in a locking threasd insert, the other was a drop low strength loctite on the thead of the plug.

Rob
RET
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Location: Toronto, Canada

Post by RET »

Two things:
First, if you use an allen key to tighten up the socket hd. cap screw, you won't have to worry about it ever coming loose and second, if you take a close look at Bill's picture, you will see that the hex socket is about the only thing that stands out at all & even that isn't obvious. Try machining a standard #8-32 capscrew the way I mentioned, put it in a bit of scrap shaft & see what you think of the result. Yes, you can see it, but I think you will find its OK.

By the way, as I said, the #8-32 greasing adapter is made from a standard #8-32 socket hd. cap screw with a 1/16" hole drilled down the middle. While socket hd. capscrews are hard, they can still be machined with standard high speed steel tool bits.

Richard Trounce
10 Wheeler Rob
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RE: end screw

Post by 10 Wheeler Rob »

Hey,

I like the idea of the screw head seeting into the 60 degree center drill cone. The cone tends to self locking when you tighten it up, and it is nice to have centers left in the axles ends of the finisnhed assembies. Very useful for checking wheel run out, polishing the wheel rims and such.

Rob
Bill Shields

Coming out

Post by Bill Shields »

I have no idea if I came up with this idea on my own or not...I made the axles 25 years ago...but it doesn't seem to be a 'hurricane' of a brain storm on my part...just good "maintenance man's" way of doing something.

I have never had one of my modified screws / fittings or whatever ever come loose...what is the load that would MAKE them come out in the first place?

I start with flat head SHCS at the standard taper and work them down to the 60 deg for the center. After everything is painted black (when the loco is FINALLY done, it WILL be painted..in a few places).....

Sure, some of our British friends would argue that we need LH threads on the one side to prevent rotational inertia from causing the screw to loosen, but then these are the folks that also have Lucas Electric components in automobiles built in wet, damp environments....so pay as much attention to that agrument as you feel it deserves.

I use a 'push' type of hand-held grease gun with a rubber-tip on the end...commonly used by motorcyclists (of which I am one). This way I don't need to make any special fittings..just stick the schnozzle in the hole and push on the end of the injector..plug the hole with the SHCS and on to the next.

I use free-floating o-rings for grease seals on either side of the axle bearing. They don't actually 'rub' on anything that rotates..but they catch grease and dirt and keep things nice and clean...and they DON'T blow out if the bearing is over greased.

I have no objection to off-the-shelf grease seals..just that their OD tends to be a bit large for our axle boxes...

RET:

the allowable load on a bearing is also a function of the speed...at really low speeds, bearing load tends to be somewhat lower than the 'standard' quoted load. Not to worry, we are still well below what a good needle will handle...but if you are ever doing mechanical design and looking closely at bearing load...be aware of speed please.

Some needle bearing manufacturers also rate the loads on their bearings for low speed / reciprocating loads...and you would be shocked at how 'small' a load they can be rated for.
10 Wheeler Rob
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Location: East Hartford, CT

Thanks Bill

Post by 10 Wheeler Rob »

Bill,

Thanks for the advise, very helpful.

Both of my Grandfathers were old time farmers. Went form horse days to the modern equipment. The old equipment did not tend to have bearing seals, rubber boosts and such, and we were told to grease until it pushed the old out.

They had a lot of ewuipment like combines, and drills that were onluy used for a couple of weeks of the year. They also greased before they put the equipment in the shead for storage too. Flushed dirt and moisture out for storage. There equipment lasted a long time, where as the guys that just left everthing parked out doors and did not take the time to maintain it did not.

I was one of the youger grandsons so did not get a lot opertunity to learn a lot of there skills. I know one of them had done a lot blacksmithing in his younger years also.

Rob
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LivingLegend
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Grease or Oil? (CORRECTION)

Post by LivingLegend »

CORRECTION (to my first post on this thread.... )

""Another variation to the above idea is to install the grease fitting ONLY when lubing and then removing it and screwing in a plug to seal it until the next time you need to re-lube

Regardless, with this method the grease/oil fitting is hidden and you won't have an OVERSIZE out of porportion hole/fitting/screw/plug in the visible face of the axle that sticks out like a sore thumb! Of course, if your bearings don't have a lubrication hole in their outer race you won't be able to use the above idea.""


Ment to say "lubication hole in their INNER race" as this discription was for the method lubing bearings through the axle ends.

LivingLegend
Last edited by LivingLegend on Thu Jun 29, 2006 12:36 pm, edited 2 times in total.
Bill Shields

innie / outie

Post by Bill Shields »

I knew what you meant...

Guess that means that I am as screwy as the rest.....
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LivingLegend
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More Ideas to Share

Post by LivingLegend »

More Ideas to Share.....

Something else you can do if you use the "lube through the axle end" method:

As mentioned in other posts here, you can use a standard "Zerk" (or other) fitting in an adaptor with a 8-32 (or 10-32) thread on the end where it screws into the axle. If you use that method, try this little trick...

After tap drilling and before tapping the axle, counter drill (8-32 or 10-32 clearance depending upon the thread chosen) about 1/8" or so in from the base of the 60-degree center. THEN TAP. This will do a couple of things:

(1) The starting of the threads won't be seen at the base of the axle's 60-degree center "cone" and the end of the plug will be recessed into the axle and it (along with it's hex (or slot) head) will be less visible.

(2) If your adaptor has a long tube that extends past the axles end, the recess will support it to help keep the side strain from breaking it off at the thinner, weaker sections of it's small diameter threads.

To make an adaptor that won't break off, you can take a piece of hex brass that's width across it's flats is wider that the axle center's major diameter. Turn down the hex on one end and thread it to fit the axle threads to a length just long enough so the adaptor's shoulder tightens up to the axle face. Then drill and tap the opposite side to receive the grease fitting of choice. This type of adaptor would lessen the possibility of a long adaptor tube snapping off inside the axle.

Any other ideas out there to give 10 Wheeler Rob some more choices/options to accomplish what he wants to do???

LivingLegend
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