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snowman
06-19-2008, 01:55 PM
VERY VERY BASIC....

I need to spin a drill bit at 1000 RPM (for drilling-duh).

No side loads, nothing fancy at all.

What type of bearing would you use?

ahidley
06-19-2008, 02:25 PM
a ball bearing that takes axial loads for smallish bits and perhaps a tapered roller for larger bits.

http://www.skf.com/files/004858.pdf
Something with a race shape like the 7319 BE listed above

snowman
06-19-2008, 02:46 PM
so a tapered roller like a set of trailer bearings would work?

Norman Atkinson
06-19-2008, 05:19 PM
Currently( when my hand heals) I am finishing a mill drill/staking tool whatever called a Universal Pillar Tool by G H THomas.

He recommended nothing more than sintered bronze bearings on a 7/8th MS spindle

There has been a lot( Practical Machinist) on chucks for small drilling-
you may be interested in this.

Cheers

Norman

J Tiers
06-19-2008, 10:14 PM
On the other viewpoint, I have a small OLD drill press, it takes the very smallest size Jacobs chuck, and the one on it may be original... it still has the patent date, putting it in the early part of last century...

It has a (very non-standard type of) thrust bearing in it, but is otherwise a very basic small drill press taking #80 to 1/4" drills..... with plain bearings for non-thrust loads. They are steel on cast iron bearings.

wierdscience
06-19-2008, 11:14 PM
When I built this a few years back-

http://img.photobucket.com/albums/0903/wierdscience/MULTI.jpg


I used oilite bronze for the radial loads and a ball thrust bearing for the thrust load.It has worked well at 800rpm for years now.It just depends on how big a bit you plan to use.

Norman Atkinson
06-20-2008, 03:10 AM
My sintered bronze is actually Oilite. I was unsure of being able to obtain Oilite on your side.

Jerry is quite right about hardened bearings. Quite a lot of watchmakers and clockmakers had them. My Pultra( Smart and Brown) 10mm lathe had them.
It was oiled with a wick( and no rude remarks from the back, please)
They are in lathes.co.uk
The UPT is in Workshop Techniques by G H Thomas(Tee)

Cheers

Norm

Mark McGrath
06-20-2008, 03:16 AM
For small drills light loads I would use angular contact bearings.One at each end back to back.

davidh
06-20-2008, 07:08 AM
open the case of your electric hand drill. . . that will give you a pretty good idea of what you need.
davidh (the tooldoc )