Boring To Seat A Ball Bearing

[prasad]

I have a task where I have to cut a few holes or bore to seat a ball bearings. The part is aluminum bar, nearly 36 inches long and therefore this work can not be done on my 9x19 Grizzly G4000 lathe. The other machine I have my mini-mill. I have tried test cuts using my milling cutters. I ran into two problems.
1. I don't have milling cutter of the right diameter to suit the bearing diameter.
2. The surface finish I got when I plunged the end mill into aluminum was not smooth like I would get if I had cut this bore on a lathe.
Would a new end mill of the same diameter as the ball bearing work?
How to get better surface finish?

I will buy new end mill cutter(s) if there is a solution to my problem. Seeking your advice,

Thank you
Prasad
Eastern PA

 

[Ulma Doctor]

you may wish to drill/mill slightly undersize and ream the hole to desired dimension.
both operations could be done with a hand held drill if the bores are not relatively large

 

[JimDawson]

you may wish to drill/mill slightly undersize and ream the hole to desired dimension.
both operations could be done with a hand held drill if the bores are not relatively large

:+1:

 

[Wreck™Wreck]

Is the ball a fluid seal?

 

[Tony Wells]

A common terminology issue that needs to be clarified. Is this a single ball, or a ball bearing assembly with an inner and outer race and individual balls with a cage?

 

[RJSakowski]

Dimensions and tolerance requirements would help. Also, the function of the ball as that will affect the process used. Are you machining the end of the bar? Round stock, flat?

I would not trust an end mill to cut a hole to nominal size. An undersized hole and boring bar to finish would be a better choice.

 

[Mark_f]

I would use a boring head in the mill to bore to size.

 

[prasad]

you may wish to drill/mill slightly undersize and ream the hole to desired dimension.
both operations could be done with a hand held drill if the bores are not relatively large

Thanks. I should have given this info in my original question - the bearing is type 6202. I am not sure if I can use a handheld drill to drill a 35 mm hole about 11 mm deep.

Prasad

 

[prasad]

Is the ball a fluid seal?

The ball bearing is a standard variety - type 6202ZZ

Thanks
Prasad

 

[Tony Wells]

I think you can safely forget using an end mill to plunge a proper size hole for a press fit in your application. A reamer that size will be rather expensive and pretty long. And as always, there are pre-ream conditions that must be met to achieve the results you need.

The proper thing, IMO, is what others have suggested. That is a boring head. Drilled holes are seldom placed accurately in terms of assemblies where ball bearing supported components are used in the first place, even if you could somehow hit the size. Center drill or spot drill, then drill under size, then bore to finish size and on location. That's the most common approach. There are some crude, but effective, tricks to using a fly cutter to bore a precise hole that you might want to look at if you do not have a boring head.

But first, I think I'd forget using an end mill for this.