This is not my idea, but one pinched from my days on flying machines, when the grease in ball races was changed every so many flying hours. A real horrible job, strip down control linkage, re-grease, reassemble linkage. Well over a days work on an old chopper.
Anyway, less of my reminiscing, back to describing how it works.
My ball race collection has grown to desperate proportions over the years. The problem is, grease or oil in bearings has a limited shelf life, and most of mine are past their sell by date, so they need to be given a new lease of life, not all at once, just when I come to use them on the engines I build.
This article is about a simple little tool to re-grease bearings. Fairly easily made, and can have extra holders made, to make it a bit more versatile.
I will be giving very few dimensions on this article, because it can be made to almost any size to re-grease whatever size is feasible. I will be giving you the sizes for the one I made, and maybe a few recommendations.
I have only ever used one for metal shields, I don't know if it will work with rubber ones. You will have to suck it and see.
This first sketch shows how it will work.
The grease enters thru the nipple, thru the centre of the race, into the chamber underneath and is then forced thru, past the metal shields, pushing the old grease out and leaving nice new grease inside.
At the bottom of the sketch there is a cross section of a ball race showing the bits I will be talking about in the article..
This is what I made mine out of. Almost anything you can get your hands on will do.
I used a bit of 10mm threaded rod for mine. The bearings I am going to be greasing with this tool will be either 5 or 6mm (or 1/4") internal bore. If you are going to be doing larger ones, increase the size of the rod accordingly. Don't worry about not having threaded rod, a long threaded screw will be just fine, as long as it will drill.
The grease nipple will be what is standard for your area of the world, I spent over two hours this morning trying to track these down. It seems that most bearings nowadays are sealed for life. These are a standard 6mm thread.
It doesn't have to be ali for the block, it can be almost anything, as long as you can get a nice smooth threading action thru it.
The brass at the back, again can be almost anything. I just used what was near to size in my recycle box.
That just about covers what is needed, so I'll get down to making it.
I squared up the block. IT DOES NEED TO BE SQUARE, the size isn't critical, within 25 thou is well close enough. In fact the width on mine, instead of 1/2" as shown, ended up at about 5/8".
Here it shows the main block marked up. I scribed lines on the side faces 1/2" from the edges. The lines on the top are 1/2" from the edge and midway position on the thickness.
This now shows a critical bit. The block, sitting on paras was drilled at the marked position, right thru with a 1/4" drill, this was followed down with the tapping drill size for my threaded rod to a depth of 3/4". While it was still mounted in the miller I tapped it out to size.
This is the result.
Next bit.
I hacked out close to the lines using my bandsaw, it saved me a lot of effort and time on the miller. You have to make sure it is square in the miller. The inside face of the block with the 1/4" hole in it has to be square with the threaded rod. This is why I said earlier, if you can get it all square, it can be dropped onto paras and everything automatically stays square.
I machined the middle out to the lines (again not critical).
As soon as you take it out of the vice, find the largest drill you have that will fit thru the threaded hole and give the 1/4" hole on the inside face a nice chamfer.
The opportunity was taken at this stage to clean out the threaded hole to a nice spinning fit, not too tight, as it will allow for very slight discrepancy in being square.
This is the block finished.
These next few pics show how I machined the threaded rod.
The end was faced off, and a 1/16" drill was put into the end for a distance of 1/2".
The end was then chamfered, I used a chamfering tool, if you don't have one, kick over your topslide to the required angle and use that to put the taper on. Mine is about 60 degrees, anything up to 90 degrees should do. If you go shallower than 60 degs you run the risk of it going too far thru the bearing centre hole. This chamfer is put on until the end face bit of the taper is about 10 thou from the centre hole.
To tidy the end up, I cut back the threads a little bit, it is not necessary, just me being fussy.
Once that was done, the rod was put the other way around in the chuck, faced off, then drilled down with the correct size tapping drill for the nipple until it just reached the 1/16" hole at the other end. The thread was then put in for the grease nipple.
Two parts done and fitted together. Now onto the bearing carrier.
These do require a bit of care, and a selection can be made to allow all different sizes of bearings to be re-greased.
Mounted up the piece into the chuck, and turned a spigot 3/8" long by 1/4" diameter, a nice sliding fit into the hole in the block. This was then parted off leaving 1/4" thick flange.
It was flipped over in the chuck and was faced off to a thickness of about 3/16". A 1/16" hole was then drilled to a depth of 3/8".
This bit can be a little tricky, I ground up one of my flywheel recessing tools and it did the job admirably.
This next bit requires you to look at the sketch if you don't understand what I am on about.
The recess is cut to a depth of 3/32", or thereabouts, no deeper though. The inner edge of the recess is the same diameter as the inner race diameter, the outer edge, the same diameter as the outer race inner diameter. Say that after you have had a few beers.
The final operation is rather critical. Remove 2 thou (0.002") from the face of the spigot at the centre of the recess. The reason for this is that when ball races are made, the inner race is usually slightly longer than the outer race, to prevent binding of assemblies. If you don't do this, grease will come out under the outside races
Away from the big playthings now. Onto the drill press (or miller). The part was held in the vice at about 45 degrees. A 1/16" hole is drilled from the bottom corner of the recess until it connects with the 1/16" hole previously drilled in the part. Try to keep it square, and try not to damage the top edges of the recess. A bit tricky but if eyeballed right it will be good enough.
Give everything a good cleanout, you don't want to be putting swarf into your bearings.
You can make different sizes of these bearing holders to allow you to do a lot of other sizes. This one will effectively grease both my 5 and 6mm bearings.
In fact if you made a little adapter to go between the bearing and threaded bit, my little offering could grease up to 2" diameter.
The finished tool.
And now with a bearing fitted, ready for a new lease of life.
Do not tighten down very hard, a good hand tight should be good enough. A bit of grease might come out of places it shouldn't, but if it comes out from the shields on top of the race, it has done it's job. Just wipe off excess when you have finished.
All I have to do now is buy a grease gun and grease. Doh!!!
This little post DEFINITELY took longer to compose than it took to make the damned thing.
Now go forth and grease your ballraces.
John
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