Re: [CAD_CAM_EDM_DRO] Angular Contact Bearings and Ballscrews question

JanRwl@... wrote:

> Next, I had to build two small application-specific (special-application)
> woodworking lathes with a SINGLE spindle-speed (3600 RPM), and was told to
> use "Dual Race angular contact ball-bearngs, NOT tapered roller bearings".
> Did. Kinda expensive, but Grainger's had those right in the catalog! I was
> also told to use a "normal" single-race ABEC-5 bearing at the "left end" of
> the spindle, but mounted "normally". This spindle was kinda short (11"? I
> forget, now!), and there was no arrangement to "float" that latter bearing,
> but all is OK. I have run the machine for hours with no problems. OH! I
> was also told to use a "muffin fan" to blow forced air through the headstock
> (the motor is 4L-V-belt connected, below) to cool the bearings! They DO warm
> up a bit! After thousands of hours, the "permanently lubricated, sealed"
> bearings are still just fine, but I kinda wish, somehow, there was some way
> to re-lube those, now and then!

You can relube sealed bearings. For grease, braze or solder a hypodermic
needle to a grease fitting. You snap it into the grease gun chuck and then
work the needle under the seal where it rubs on the inner race. If you do
this carefully, you can relube the bearings without harming the seals.

If you have a grease gun modified for oil, you can use it to inject oil into
the bearings.

3600 RPM is quite fast for tapered roller bearings. So, ball bearings are
a good choice at that speed.

> The only machine I can recall that had tapered roller-bearings (aside from
> "car parts") was an OLD Atlas lathe. Some folks "love" those, but they were
> kinda obsolete! I have NO clue if "tapered" is right for any new lathes,
> etc. Just no idea. But for high-RPM use, the dual-row angular-contact is
> right! Yep! Scho' nuff!

Many lathes still are made with tapered roller bearings. It does seem that
the highest quality use either ball bearings or journal types.

Jon