Drilling a ball bearing.

[cheb]

IIRC some brass musical instrument tubes are trued after manufacture by forcing a series of ball bearing through them.

 

[Dapph2]

Using a simple hydraulic ram set up and a pipe clamp in the vise , can you push the ball in a cup rather than pull it on a rod ?
Then once it is well in the tube retract the ram . add a few more bearings and reassert the ram . Repeat as needed till the third ball breaks free then add a rod instead of bearings to clear the tube out . It is how brass smiths form perfect cylinderical tubes for the sliding tubes on brass musical instrument .
I seem to recall it's how shot gun barrels are trued up as well ........ pushed instead of being pulled through ??

 

[dave h 2]

If you still need to drill a ball you can centre it by chucking something pointy in the drill and trapping a steel rule lightly between the point and the ball. Play tappy tappy with a hammer on the vice till the rule stays level when you rotate the rule. Lock the vice down tight.
Chuck a stone and grind off the chrome.
Chuck carbide drill and pray.

 

[Cobbler]

IIRC some brass musical instrument tubes are trued after manufacture by forcing a series of ball bearing through them.

I I remember correctly, that was how to fit Ford 100e little end bearings, they were thin wall, & you pressed them in with a ball bearing in them, then pressed the ball out to true the bearing. Never done it, just what I was told when I rebuilt my Ford special years ago.

 

[Alan Reynolds]

Good luck is all I’ll say. If it’s a decent quality ball bearing its hardness is comparable to HSS. You’ll do well to “drill” through it with anything. You might do it with carbide, spark eroding could be your only reasonable option.
Either anneal or normalise first for your best chance, should be able to drill with HSS then. Does it need to be a ball bearing?

Thanks for the reply.
Yes it has to be a ball as it has to be pulled around à bend in the pipe.

 

[Seadog]

I I remember correctly, that was how to fit Ford 100e little end bearings, they were thin wall, & you pressed them in with a ball bearing in them, then pressed the ball out to true the bearing. Never done it, just what I was told when I rebuilt my Ford special years ago.

It's known as burnishing.

 

[8ob]

Thanks for the reply.
Yes it has to be a ball as it has to be pulled around à bend in the pipe.

Not sure what size you are after but these things are cheap to buy.Balls

Bob

 

[Agroshield]

Yes it has to be a ball as it has to be pulled around à bend in the pipe.

Would the string pulling the (single) ball not try to cut the corner and dig into the inside of the bend?

I would think it might need multiple balls to keep the rope centralised.

 

[tom2207]

must be strong string and a soft pipe ,,, the idea sounds good , but as to how practical it is I dont know.

 

[Dapph2]

Would the string pulling the (single) ball not try to cut the corner and dig into the inside of the bend?

I would think it might need multiple balls to keep the rope centralised.

That's why I suggested using pushed in the tube balls . they will simply run with any bends with ease and there is no chance of the balls breaking off the pulling bar , rod, wire or cord to become stuck half way along the tube . Annealing the tube or even getting it red hot if it is a thick walled tube would help too.
There are a few reasonable YouTube videos showing how the precision slide pipe work of trumpets , cornets & trombones are formed and a few wrt to making precision drawn steel shotgun barrels .

 

[6ply]

Not sure what size you are after but these things are cheap to buy.Balls

Bob

Good shout.

Just don't go searching for an adults toy with metal balls on a string.

 

[Cobbler]

Good shout.

Just don't go searching for an adults toy with metal balls on a string.

What, one of those newtons cradle things with 5 balls in a frame? Can’t see a problem with that