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Removing needle roller bearings ?

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confused.eng03/05/2011 22:50:21
19 forum posts
2 photos
Ever wished you'd kept your mouth shut?.
This is one of those 'You know how to fix things don't you - can you just have a look at.....' jobs.
 
The problem: the needle roller bearings pressed into the ends of a tube have disintegrated and its anybodies guess where the needles have got to. The bearings are pressed into the ends of a tube up to a shoulder. Tube is 25mm OD, bearings are 20mm OD. Can't get bearing puller in, can't tap it out from other side. Can't heat tube as it will damage outer surface.
 
Only thing I can think of is a small die grinder to cut through the outer bearing housing and then hopefully the housing can be encouraged to come out.
If anybody has any better ideas on getting these damned fiddly things out.
Pat Bravery03/05/2011 23:03:33
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96 forum posts
24 photos
Can you drive a thin punch between the bearing runner and the tube to collapse the bearing?
dcosta03/05/2011 23:17:53
496 forum posts
207 photos

Hello Philip.

You do not say what is the outside diameter of the roller bearing.
If it is slightly higher (and usually they are...), then you can make a metal disk hard enough and cut two oposite archs to allow the disc to pass inside the bearing. Make a slot hole in the center of the disk through which must pass a threaded rod with a nut on the end. The oval hole is intended to allow the passage of the disk inside the bearing.
Outside of the tube use a metal piece with a round hole to make the threaded rod to pass through and use a nut to pull the outer ring of the bearing out.


I hope I was clear (?) and that this idea has helped. The language may be a barrier...


Best regards
Dias Costa


confused.eng03/05/2011 23:59:50
19 forum posts
2 photos
The tube is actually used as a roller with the outside surface needing to be a smooth unblemished finish. The overall diameter of the tube is 25mm (1" in old money - actual diameter not that critical but need to be parallel). There is a a needle roller bearing pressed into each end of this roller and the outer diameter of the bearing housing is 20mm.The bearings are on the inside of the tube.
Through the centre of the tube is a 10mm shaft that has the inner bearing surface pushed onto each end and held in place with 'C'/'E'/'Cir' clips or something like (them things that get lost every time they ping off the shaft when you remove them).
The tube/roller is about 300mm in length, it is basically thick walled tube turned parallel and machined to take the bearings at each end. The remaining wall thickness is about 2.5mm where the bearings are.
The awkward thing is, is that the internal shoulder in the end of the tube is as deep as the thickness of the outer part of the bearing housing so I can't get anything on the inside side to pull the bearing housing out.
The bearings used come apart easily into three parts, inner housing - 10mm internal diameter, the needle roller cage(missing on one end) and then the outer housing - 20mm outer diameter (stuck in end of tube).
 
Apparently the idea in using needle roller bearings was to allow the outer tube part drift slightly on the inner mounting shaft - problem has arisen because the outer surface of the roller gets cleaned with some solvent (like Amberclean ME20 - that stuff shifts anything from everything) that has stripped the grease from the bearing, then put back together and run dry at high speed.

The material the tube is made from is thick walled mild steel tube, so trying to collapse the bearing internally is most likely not possible unless is was cut somehow.
 
I'm thinking, making him some new ones might be the best bet.

confused.eng04/05/2011 00:08:55
19 forum posts
2 photos
 
Hopefully this drawing pinched from some info about the machine will help.
The hatched parts in the drawing are the two halves of the bearing housing and the needle rollers sit between them.
 
Nicholas Farr04/05/2011 00:16:16
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3988 forum posts
1799 photos
Hi Philip, how about trying two or three maybe, weld beads on the outer part of the bearing, and then letting them cool and shrink. I appreciate you don't have much room inside to get much of a weld in, but with care it should work as long as you don't have it too hot and burn through and welding it in forever. Or you may be able to spot tack a bolt head onto the inside and fix some kind of slide hammer to the bolt to tap it out. 
 
Another approach could be to get it in the lathe and boring it thin enough for it to collapse, providing it's not too hard of course.
 
Regards Nick.

 

Edited By Nicholas Farr on 04/05/2011 00:21:03

JohnF04/05/2011 00:38:00
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1243 forum posts
202 photos
Hi Phillip, hydraulics might work, have you ever removed the gearbox shaft support bush from a car fly wheel? Blind hole with a brass bush!!
How good is the finish and ID of the long tube? for this to work it needs to be pretty good or you could try an O ring in the end of the long bar below.
 
The idea is make a rod long enough to fit inside the long tube 300mm less the bearing length 16mm then you need a short length of bar turned to the ID of the bearing shell.
 
Insert the long rod and seat firmly on one end on something solid, put some grease in the cavity left at the oposite end, insert the "plug" into the bearing shell and strike with heavy hammer--the grease will/should flow under the shell and push it out.
 
Good luck John
Richard Parsons04/05/2011 05:15:48
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645 forum posts
33 photos

Philip


As you cannot heat the outer case you might try cooling the inner bit (the Outer race bearing). If the ‘Domestic Director’ is not looking slip one into the deep freeze and see what happens. Wear good thick gloves!


Though it would all depend on what the roller is made of. If it is aluminium then that cat will not jump! (Coefficients of thermal expansion)


Good luck


Dick

John Coates04/05/2011 06:32:00
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558 forum posts
28 photos
Why not turn a 16mm long cylinder to fit in the inside diameter of the bearing then bore this with a taper and slit with three or four slits. Then turn a taper to match but slightly larger so when tightened into the cylinder it forces the cylinder to grip the ID of the bearing as the slits allow expansion.
 
Bore through to take a threaded rod (8 or 10mm). Weld a nut on the end of the rod as this will stop it all falling into the tube. Thread the cylinder and taper onto the rod and insert into the bearing. Next put a washer and nut onto the rod and tighten so it forces the cylinder to expand and grip the bearing. Grip the tube in a vice (protect outer surface of tube). Now make a U frame with a flat plate drilled in the centre with the diameter of the threaded rod. Support this against the face of the vice. Now put put a washer and nut on and tighten so that it pulls the bearing up.
 
Basically what I'm describing is a bearing puller !
 
john
Steve Garnett04/05/2011 10:22:16
837 forum posts
27 photos
Drop something really heavy on it, say 'whoops' and make a new one.
Pat04/05/2011 10:46:57
94 forum posts
1 photos
Hi Philip
 
I keep PH 'Crack It' on the shelf as the first line of attack on bearings and other parts that have got stuck. This is an aerosol of freezer and penetration lubricant all combined in one can. Spray on the inner part of the race way which is instantly frozen. The resulting thermal shock opens a gap between the inner and the outer letting the penetrating oil get between the surfaces. Crack-It is used extensively in motor repair shops for freeing recalcitrant parts.
 
Here is a link to one possible online supplier if you don't have a local garage tool supplier.
 
http://www.tools-supplies.co.uk/ph-crack-it-1694-p.asp
 
You may still need to use a puller made of oval washers as these thin outer shells are not easy to get a grip on.
 
Do heed the safety warnings to avoid frost bitten fingers etc!
 
Hope this helps - Regards - Pat

Edited By Pat on 04/05/2011 10:48:44

Les Jones 104/05/2011 10:54:41
2292 forum posts
159 photos
Hi Philip,
How about boring a rebate behind the bearing to a diameter of 15 - 18 mm and then using Dias Costa's suggestion.
Les.
PekkaNF04/05/2011 11:32:13
96 forum posts
12 photos
There is one trick I have used to get out stubborn bearing outer rings: Fix pipe or flange to bearing and tack weld. I admit that I have used this only few times when I have got nothing to loose, but it works surpricingly well.
 
Once there were no provision to pull out the outer race and and gearbox case was made out of aluminium...I tack welded few really small tacks - just to try it and the race come out just with a gentle pull when I tested the feel of the tacks.
 
I would gues that just few little zaps of mig might compress the thin needle roller bearing just enough to ease it out. Wet rag might keep the outside cool and prevent it from warping.
 
PekkaNF
confused.eng04/05/2011 11:38:16
19 forum posts
2 photos
Had to go earn some pennys to keep SWMBO in the life style she hasn't become accustomed to. (Playing with a mattress spring assembly machine today).

Will give your suggestions ago, but will probably be the weekend now.
My personal favourite is Steve Garrnets idea,
Maybe the simplest in the long run.
Martin W04/05/2011 12:27:45
940 forum posts
30 photos
Philip
 
Is there any chance that using solid carbide tool you could turn the bearing shell to a thickness that would allow you to break out the remaining bits; that said I don't know whether carbide will cut this material but I have use solid carbide drills to drill into some very hard metals successfully.
 
Cheers
 
Martin
chris stephens04/05/2011 12:52:55
1049 forum posts
1 photos
If you like to experiment, how about testing the shear strength of Loctite ? If you make a plug and stick it in with Loctite 638 (the really strong retainer) following the instructions to the letter, and then drift it out from the other side. Absolutely no guarantee that it will work but the it just might.
If one of the plugs you bond in has a hole in the middle you could bond both in at the same time (to save time waiting for the retainer to set) and use two different sized drifts to biff out the outer tracks.
chriStephens
Martin W04/05/2011 13:42:52
940 forum posts
30 photos
Philip
 
Looking at it from a different angle is there any merit in checking the bearing surface of the offending item to see if it has sustained any damage, if not would it then be possible to fit a set needles & cage from a similarly specified new bearing?
 
Cheers
 
Martin

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