Round Shaft holding using Ball Bearings and a Box Wrench technique

[abextra]

I was doing a bearing change on my tool post grinder spindle and noticed 2) small drill spot on the shaft. Intuitively I knew what it was for but cant remember where I leaned about this technique and wanted to research it a little because it works so well. Has anyone ever seen this written up or know more about it orign?
Thx
Rob

 

[Scottl]

I believe it is a variant of a roller clutch.

 

[eKretz]

This looks more like dimples for set screws. I can't imagine they would intentionally put a high speed shaft out of balance for such a thing otherwise. You stand a very good chance of mushrooming the edges of those dimples doing things like that.

I use a strap wrench for such things.

 

[gbent]

Or get fancy and get Petol Suregrip friction tongs.

 

[Clive603]

Presumably rollers will work too. Possibly better given that contact is line rather than point which ought to give more grip.
Could turn rollers to best size too rather than using the nearest size ball out of the handy stuff box.

Clive

 

[MCritchley]

Or get fancy and get Petol Suregrip friction tongs.

Thanks for posting that, didn't know that was a product, neat product line. I typical just make something up out of a shaft collar if i need to grip a shaft.

 

[Scottl]

This looks more like dimples for set screws. I can't imagine they would intentionally put a high speed shaft out of balance for such a thing otherwise. You stand a very good chance of mushrooming the edges of those dimples doing things like that.

I use a strap wrench for such things.

I've many times used thick leather strips in a pipe vise to hold stuff securely without marring. Just finished cutting some plated 1" pipe used with setscrew fittings (Lowes) for a railing. Held nice and firm while using a 2" pipe cutter and no trace of marks. I used thick leather because of the teeth in the pipe vise.

 

[johnmontrose]

Possibly better given that contact is line rather than point which ought to give more grip.

If the diameter of the ball is bigger than the diameter of the dimple, that is also line contact albeit a circular line.

 

[L Vanice]

I prefer to use soft copper sheet to avoid marking a shaft or similar work.

Easiest way to get a small piece of copper is to saw a piece of water pipe, flatten it out and anneal it. Copper water pipe can be found at any hardware store, but actual sheet copper is not so common. I do not throw out old copper pipe; it can be used for other things.

Larry

 

[abextra]

There are no set screws on handened high speed spindles because of runout and imbalance issues and strap wrenches are not effective on small polished surfaces. I agree it is a locking clutch type system and it works so well and with infinite range and little damage. I was more afraid that the box end wench would give it up. Magnets helped to hold the balls during setup.

 

[just Dave]

In machine tool disassembly I have many times turned to a heavy smooth jaw vice. 4” is a good size to get in on lead screws transmission shafts spindles and such. Great grip…no marks.

 

[reggie_obe]

I prefer to use soft copper sheet to avoid marking a shaft or similar work.

Easiest way to get a small piece of copper is to saw a piece of water pipe, flatten it out and anneal it. Copper water pipe can be found at any hardware store, but actual sheet copper is not so common. I do not throw out old copper pipe; it can be used for other things.

Larry

Copper sheet: roof flashing, available even in Home Despot.

 

[cyanidekid]

Copper sheet: roof flashing, available even in Home Despot.

Flashing is pretty thin, copper sheet is Easy to get, McMaster, online metal places, etc

 

[eKretz]

There are no set screws on handened high speed spindles because of runout and imbalance issues and strap wrenches are not effective on small polished surfaces. I agree it is a locking clutch type system and it works so well and with infinite range and little damage. I was more afraid that the box end wench would give it up. Magnets helped to hold the balls during setup.

Not true at all. If they're added they are compensated for and the assembly is balanced together. My point was that I couldn't see that feature being added for the purpose you claim. And that shaft does not look very hardened at all to me in that vicinity, just looking at the visible wear pattern. It looks like it has quite a lot of galling and fretting. What actually mounts there while the unit is in operation? A pulley?

And I have no issues using a strap wrench on a small diameter hardened polished surface. Try one with a rubber or rubber coated nylon web strap...

Annealed copper also works very well, as Larry and a couple others pointed out. I keep old copper water pipes for the same purpose as he does.

A ball bearing one way "roller" clutch generally has a tapered groove to obtain lockup in one direction. Same with the cylindrical roller version. I don't see that here.

 

[dlaw]

Copper sheet: roof flashing, available even in Home Despot.

For polished shafts (gun barrels) I have used thin rosin coated lead sheet in a barrel vise.

 

[richard newman]

I've used a wood block bored to size and split. But then I'm a woodworker...

 

[rawen2]

abextra, You should post this in the tips thread:

Tips in general, little discussion , just the tips,

Tip one: a good smear of grease on the tap flutes will hold/retain most of the tapping chips Tip two: Zip-lock bags Sharpy marked make a decent small or any parts for OK safe storage. Tip three: Hold your scale on an angle, or straight edge and look past to something straight or horizontal to...

www.practicalmachinist.com

 

[ratbldr427]

I just bore some flat plate,thickness determined by the job, and split/saw one side and clamp that in a vise, biased on the split side, no damage and plenty of holding power. By the time I screw around looking for something, I can bore something that will work. Tubing will work and a little quicker but the scrap rectangle or square plate works best.

 

[john.k]

The Parmelee chain wrenches are the best permanent solution,and you know for sure they wont wreck anything ....made in the USA .

 

[abextra]

Not true at all. If they're added they are compensated for and the assembly is balanced together.

ANSWER: Balance issues at .400 from the center line is not possible.

My point was that I couldn't see that feature being added for the purpose you claim. And that shaft does not look very hardened at all to me in that vicinity, just looking at the visible wear pattern. It looks like it has quite a lot of galling and fretting.

ANSWER: A bearing inner race mounts on what you call Gauling & Fretting and its mostly retaining coumpound from where the race sat.

What actually mounts there while the unit is in operation? A pulley?

ANSWER: Nothing mount there its open space next to the bearing.

And I have no issues using a strap wrench on a small diameter hardened polished surface. Try one with a rubber or rubber coated nylon web strap...

Annealed copper also works very well, as Larry and a couple others pointed out. I keep old copper water pipes for the same purpose as he does.

A ball bearing one way "roller" clutch generally has a tapered groove to obtain lockup in one direction. Same with the cylindrical roller version. I don't see that here.

ANSWER: No one said it was a roller clutch? In fact its should be obvious it has full lock on the shaft.
Did you catch that I was afraid that the box end wrench would pop from the applied Torque!

A Collet or a Chuck is better than this bearing/wrench tool..but all of these blow away a strap wrench..