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Posted by Bernard Arnest on March 16, 2006, 3:36 am
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Hi,
I was wondering if it's possible to make your own bearing channels?
I have two applications where mcmastercarr does not have what I need.
Are there end mills with semicircular tip profiles to mill channels for
balls of that diameter?
thanks!
-Bernard Arnest
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Posted by Wild Bill on March 16, 2006, 6:13 am
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There are endmills and arbor cutters that make radiused cuts, but I
believe you'll find that those machined surfaces would be poor for
bearing slides.
Depending upon your desired accuracy and load requirements, attempting
to make precision slides might be a lot more difficult than one might
expect.
The paths in slides that I've seen (although not that many), have been
machine ground to tight tolerances.
Additionally, the shape of the trough isn't just a single radius, but
one radius that closely matches the ball radius (with a tolerance for
lubrication), and a second radius in the lower portion of the trough,
that provides a clearance, so that the full ball radius isn't in
contact with the rail.
That doesn't sound very clear, but picture a ball positioned on the
edges of two parallel blades.. very low friction at the points of
contact.
If a slide had a full radius of the ball, the total contact surface
area would create unfavorable friction.
Two precision slides with a ball between them would show four contacts
around the circumference of the ball.
It could be possible to mill slides, but I would expect the motion to
be rough, similar to stamped steel drawer slides or similar products.
An alternative plan might be to utilize hardened, precision ground pins
between two hardened, ground flat slides, with provisions for
controlling the slide path.
WB
...............
Bernard Arnest wrote:
> Hi,
> I was wondering if it's possible to make your own bearing channels?
> I have two applications where mcmastercarr does not have what I need.
> Are there end mills with semicircular tip profiles to mill channels for
> balls of that diameter?
>
>
>
> thanks!
> -Bernard Arnest
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Posted by Ned Simmons on March 16, 2006, 10:11 am
Please log in for more thread options barnest@mit.edu says...
> Hi,
> I was wondering if it's possible to make your own bearing channels?
> I have two applications where mcmastercarr does not have what I need.
> Are there end mills with semicircular tip profiles to mill channels for
> balls of that diameter?
>
>
There's much more available for bearings than what's in the McMaster
catalog. The bearing catalogs in my bookshelf take up almost 3 feet of
shelf space. If you describe what you're trying to accomplish I'm sure
you'll get plenty of ideas.
If you just want the experience of making a bearing, sure, it's
possible. But for starters you need to specify what sort of loads,
speeds, and precision you're dealing with, and any restrictions on size
and geometry.
Ned Simmons
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Posted by JR North on March 17, 2006, 1:07 am
Please log in for more thread options Sure there are. I made a 4" dia low speed ball bearing for a project a
few years ago. Used 1/8" balls, and had an inside diameter of 3.25" Be
aware that clamping the races in a chuck will distort them, causing
uneven drag when finished. I doubt you can make a good, high speed, high
load ball bearing on a lathe.
JR
Dweller ion the cellar
Bernard Arnest wrote:
> Hi,
> I was wondering if it's possible to make your own bearing channels?
> I have two applications where mcmastercarr does not have what I need.
> Are there end mills with semicircular tip profiles to mill channels for
> balls of that diameter?
>
>
>
> thanks!
> -Bernard Arnest
>
--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
Dependence is Vulnerability:
--------------------------------------------------------------
"Open the Pod Bay Doors please, Hal"
"I'm sorry, Dave, I'm afraid I can't do that.."
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Posted by DoN. Nichols on March 17, 2006, 2:18 am
Please log in for more thread options > Sure there are. I made a 4" dia low speed ball bearing for a project a
> few years ago. Used 1/8" balls, and had an inside diameter of 3.25" Be
> aware that clamping the races in a chuck will distort them, causing
> uneven drag when finished.
If you've got two-piece jaws, make some "Pie" jaws to fit on the
chuck, and turn them in place to the intended OD of the race. Then, you
have support the whole way around. (Better with a 6-jaw chuck to start
with, of course.)
> I doubt you can make a good, high speed, high
> load ball bearing on a lathe.
Agreed -- but you can do better if you use a toolpost grinder
with a wheel dressed to the right profile to make that ball race, and
grind after turning to just a bit short of the final size. (Actually,
you should also harden the steel between the turning operation and the
grinding operation.
Of course, using a toolpost grinder on a good lathe is always
fraught with worry about damage from the abrasive thrown by the grinding
operation.
Good Luck,
DoN.
--
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
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> I was wondering if it's possible to make your own bearing channels?
> I have two applications where mcmastercarr does not have what I need.
> Are there end mills with semicircular tip profiles to mill channels for
> balls of that diameter?
>
>
>
> thanks!
> -Bernard Arnest