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Replacing ball-bearing in 3/4" drive ratchet

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Bill Phinn07/11/2018 00:22:11
88 forum posts
7 photos

I was going through some rarely disturbed old tools underneath my bench and one thing I decided it would be nice to give a little TLC to was a 3/4 inch drive ratchet that had seen hard usage at some point under a previous owner.

It still works more or less as it should, the only real defect being the ball-bearing in the square drive. As you can see, it has flattened off, and as a consequence no longer holds sockets in place. Can anyone suggest how I might best go about extracting the worn bearing and, more crucially, inserting a new one?

Many thanks for any help.

img_0742.jpg

Hopper07/11/2018 05:18:41
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2969 forum posts
50 photos

The ball bearing was probably inserted in the hole in the square shank with a spring behind it and then the hole was swaged shut by a small amount by a hollow-nosed punch that punched a circle around the OD of the hole. (Looks like that circle mark is faintly visible in your pic, hard to tell.

So for the ball to come out, the swaged lip on the hole needs to be removed. Maybe by pushiing the ball into the hole and then careful application of a small Dremel tool etc. New ball and spring would be inserted in the hole and the hole entrance swaged over with a hollow punch similar in construction to a wad punch. Or a circle of centre punch marks might do the job.

Are you sure its a ball bearing and not a positive location pin more cylindrical in shape? Have you tried soaking in releasing oil etc to see if it can be freed up to work as is?

Mike Poole07/11/2018 08:52:00
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1549 forum posts
41 photos

I think you may be onto something there Hopper, ratchets used as a production tool often have a cylindrical pin and the sockets have a hole for the pin to locate in that is drilled through so a rod can be pushed in to release it. The pin is probably not as durable as a ball bearing and has finished up as in the picture. A ball bearing conversion is probably going to be more convenient as a service tool rather than a production application.

Mike

Bill Phinn07/11/2018 20:47:43
88 forum posts
7 photos

Many thanks, Hopper and Mike, for your replies.

I think you're absolutely right about the ball-bearing actually being a cylindrical pin. I've added another couple of photos to try and better show what I'm dealing with. I forgot to mention that the pin isn't seized and the ratchet is quite useable as it is; it's just that heavy sockets (which 3/4 sockets generally are) tend to drop off the drive if you're not careful.

img_0747.jpg img_0744.jpg

Edited By Bill Phinn on 07/11/2018 20:48:51

Edited By Bill Phinn on 07/11/2018 20:54:59

Howard Lewis08/11/2018 18:47:45
1464 forum posts

Silly suggestion!

If the pin is soft enough to drill, could it be drilled out, although you will then have to take a few measurements to arrive at the correct length for its replacement.

Probably a tapping of that size would not be strong enough to pull the pin out so as to keep the original length measureable.

Howard.

Bill Phinn09/11/2018 22:54:25
88 forum posts
7 photos

Thanks for your reply, Howard.

I think I probably could drill the pin out with a bit of effort. The more difficult bit might be replacing it with a ball-bearing that functions as I want it to. I suspect choosing the size of the ball is critical: too big and I risk damaging the hole as I drive it in; too small and I may not be able to move enough material in from the lip to hold the ball in place, and once I've started to move material it may be difficult to go back. The good news is the ratchet as it is functions quite well with most of my 3/4 sockets (i.e. it still holds most of the sockets on the drive, albeit a little tenuously).

Incidentally, one of the two countersunk slotted screws you can see holding the cover plate in place is an impostor. One of the screws was missing when I got the ratchet out. I rifled through my boxes of misc. machine screws to try and find a replacement, which needed to be a 24tpi 3/16. The only 24tpi 3/16 screws I found had hex heads on them and were 1cm too short for the job.

The solution (I don't have a lathe): cut the hex head off the screw that is too short; cut the head and a bit more off a slotted screw of the same diameter but a different pitch, and bronze-braze this head and a bit more on to the decapitated replacement.

It works fine, though having a lathe would have been nice. I mean to fix my lack of one soon.

Michael Gilligan09/11/2018 23:14:29
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11911 forum posts
518 photos
Posted by Bill Phinn on 09/11/2018 22:54:25:

... I think I probably could drill the pin out with a bit of effort. The more difficult bit might be replacing it with a ball-bearing that functions as I want it to. ...

.

Have you considered bonding a small Neodymium Magnet into the hole instead ?

MichaelG.

.

https://en.m.wikipedia.org/wiki/Neodymium_magnet

Edited By Michael Gilligan on 09/11/2018 23:14:53

Bill Phinn09/11/2018 23:25:49
88 forum posts
7 photos

No I haven't, Michael, though perhaps I should have done since co-incidentally I inset 4 neodymium magnets yesterday into depressions I milled in the backs of those aluminium vice inserts you can see in one of my images in order to supplement the holding power of the rather weak magnets already there. Thanks for your suggestion.

Edited By Bill Phinn on 09/11/2018 23:27:02

Mike Poole09/11/2018 23:56:02
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1549 forum posts
41 photos

When i wanted to remove the ball from a T bar i drilled from the back so i could use a small pin punch to drive the ball out, this minimised the work on the hole as i wanted to refit the ball. Although it was quite hard a HSS drill was ok.

Mike

Edited By Mike Poole on 09/11/2018 23:57:49

Bill Phinn10/11/2018 23:12:50
88 forum posts
7 photos

Thanks for your suggestion, Mike.

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