Author Topic: rounding off pitted 2" bearings  (Read 293 times)

Offline paulc1

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rounding off pitted 2" bearings
« on: October 15, 2018, 03:41:51 AM »
So I happened across two 2" diameter ball bearings that came from an old closed down Gold mine and thought initially that I would try and make some blades out of them however after much deliberation I decided that I would buff them up and make them like new and make a presentation case for them, so I tried a flap disc and all manor of elbow grease and even considered trying to make some sort of vibrating abrasive trommel with a bucket or something but I dont know if there is an easier way to do it. so any thoughts would be appreciated.

here they are and as you can see I have tried to buff one up but not very successfully.

Offline awemawson

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Re: rounding off pitted 2" bearings
« Reply #1 on: October 15, 2018, 03:54:05 AM »
Are you sure that they were originally actually bearings, and not maybe perhaps from a 'ball mill' used to reduce the ore to a smaller size for further processing ?


https://en.wikipedia.org/wiki/Ball_mill
Andrew Mawson
East Sussex

Offline paulc1

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Re: rounding off pitted 2" bearings
« Reply #2 on: October 15, 2018, 04:12:55 AM »
Yes that is probably what they are Mr Awemawson not bearings, although i am not sure what grade metal it is.
if it is round and metal to me its always a bolly :D
« Last Edit: October 15, 2018, 04:58:41 AM by paulc1 »

Offline PekkaNF

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Re: rounding off pitted 2" bearings
« Reply #3 on: October 15, 2018, 05:52:05 AM »
I have used vinegar for rust removal.

Normal groseery store pickling vinegar (10% Acetic acid) will do very well, needs hour or two in 60C or overnight on 20C or three days in 5C temperatures (It's autumn here and I dunk them outside, or I get hungry).

When you pick them up from the windegar they liike like nothing has happened...but they feel really dirty and slimey, nylon brush will sort that out. You may want to wear whatever kichen/exam gloves. You need to wash neutralize the acid right after, normal soap and wrma water will do.

If you like them grey steel matte coloring, a half an hour into warm phosphorous accid (Tea kettle limescale remover) will do that, and wash/neuralize with mild soap, I use hot water, dry right after and oil. pretty nice.

If you need shine.....then you need to know material.

For historic show piece I prefer rusty. Maybe you have more of them and treat them differenty and then put all your balls into display :lol:

Would give someone somthening to wonder. And you could explain that they all same just treated differently. Old rust, new rust, vinegar pickled, phosphated, lisnished, tumbler finished....



Pekka

Offline paulc1

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Re: rounding off pitted 2" bearings
« Reply #4 on: October 15, 2018, 06:52:25 AM »
Pekka, thank you for replying and giving such great info, I have some stuff to think about now, I will watch the video when I get home from work and on a network, I did wonder about leaving them pitted and rusty..I like shiney
Thanks again Pekka  :thumbup:

Offline hanermo

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Re: rounding off pitted 2" bearings
« Reply #5 on: October 15, 2018, 10:27:54 AM »
A flap wheel will polish them fast .. you need high sfpm.
Glue them to a fixture, rotating via something.
A lathe (covered), battery drill, etc.

Against the flap wheel rotation.
200 rpm is plenty.
An angle grinder and 40 grit flap wheel will polish it and round it, fast.
1-2 minutes.
Maybe 3-4 rotations.
It gets really hot.

Submerge bottom in water .. so the glue does not let go.
Have a safety cage.
8 rods of any steel enclosing it is fine.

Offline paulc1

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Re: rounding off pitted 2" bearings
« Reply #6 on: October 15, 2018, 12:01:54 PM »
Thanks for the idea hanermo, I did try a flap disc but you made me think that I could tack it to a bit of barstock and put it in a drill or lathe..thanks.

paul

Offline awemawson

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Re: rounding off pitted 2" bearings
« Reply #7 on: October 15, 2018, 12:39:16 PM »
What you need is a Ball Turner ! Fix ball in end of tube, skim using ball turner, remove rotate and refix ball and start over again until all is skimmed.

Here is one that I made earlier:

https://madmodder.net/index.php/topic,9699.msg107845.html#msg107845

But there again you could make a new ball and display your original as cannon shot from the Civil War  :lol:
Andrew Mawson
East Sussex

Offline paulc1

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Re: rounding off pitted 2" bearings
« Reply #8 on: October 15, 2018, 04:28:09 PM »
What you need is a Ball Turner ! Fix ball in end of tube, skim using ball turner, remove rotate and refix ball and start over again until all is skimmed.

Here is one that I made earlier:

https://madmodder.net/index.php/topic,9699.msg107845.html#msg107845

But there again you could make a new ball and display your original as cannon shot from the Civil War  :lol:
Crikey, I really like that, I saw a similar thing done with a starrett holecutter on a wood lathe to turn a ball..amazing!