Drilling a ball bearing.

[Alan Reynolds]

Hi chaps.
Ive been asked to drill a hole in a 20mm ball bearing to insert a cable through. Hole needs to be about 3/16 in old money.
They want to pull it through a pipe to expand it slightly.what would be best to use, cobalt, carbide?

Thanks in advance for any help.

 

[addjunkie]

Id go carbide. Touch it with a grinder first, and try punching the flat spot, to get the drill to start in the right place.

 

[Rrobson]

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?

 

[Kram]

Some alternatives.. example, you ciuld turn a radiused/cone slug of silversteel and harden it in a fraction of the time, and be more suitable for the enlargement. A series of balls/cones may be easier than trying to get final size in one pull.

Another is rather than drilling the bearing, it may be simpler to tig or stick weld a rod or eye to it, which would allow the cable to be tied/spliced or directly pulled.

 

[Erie Fred]

What kind of pipe ?

 

[roofman]

Hi chaps.
Ive been asked to drill a hole in a 20mm ball bearing to insert a cable through. Hole needs to be about 3/16 in old money.
They want to pull it through a pipe to expand it slightly.what would be best to use, cobalt, carbide?

Thanks in advance for any help.

Cant help with that one except to say " now ya,ll watch this sh 1t "... might be a slim chance with a Chinese one

 

[oldbikedavey]

Spark erosion.

 

[Screwdriver]

If I had to do it I'd grind a flat and drill it on the lathe, with multiple carbide bits for when they break. Probably also want multiple balls for when the bit snaps off in one. If you're lucky the bearing will be case hardened so it might be an idea to grind that off on both sides of the part first.

What I do know for sure though, despite all the many excellent suggestions, is that the customer wants what the customer asks for. So if they want a hole, either you do that or they find someone else who will.

 

[bricol]

Ball bearing? Or bearing ball?

Bearing balls are going to be hard - 60-70Rc. And all the way through. Unless they give you a ceramic one...100Rc.

By the time you've bust a few quality 9 quid cobalt drill bits, I'd say let them go somewhere else...

 

[Gareth J]

Diamond core bit in a water bath on a pillar drill?

I've no idea if that would work, just a thought.

I'm imagining they want a bearing on a string as the pipe has bends. Can't see why you'd not do it more simply if straight.

 

[Other Daniel]

Not a suggestion, as such.
But, I'm intrigued as to why it would be neccesary to incrementally expand a tube
over any considerable length
Seems like an awful lot of trouble to go to, to achieve what exactly ?
What am I missing ??

 

[RichardM]

Do mandrel benders go as small as 20mm id?

 

[Bouledogue]

Anneal it first. Then mill a flat spot. Then drill with carbide bit(s).

 

[addjunkie]

Not a suggestion, as such.
But, I'm intrigued as to why it would be neccesary to incrementally expand a tube
over any considerable length
Seems like an awful lot of trouble to go to, to achieve what exactly ?
What am I missing ??

Are you suggesting to buy a bigger tube?

 

[badabec]

Ball bearing, BFH, drifts cut from smaller diameter pipe.

 

[pedrobedro]

Hi chaps.
Ive been asked to drill a hole in a 20mm ball bearing to insert a cable through. Hole needs to be about 3/16 in old money.
They want to pull it through a pipe to expand it slightly.what would be best to use, cobalt, carbide?

Thanks in advance for any help.

Tell them to buy a bigger pipe. This sounds like a hiding to nothing job. What are they going to pull it through with ?