Greg Postma wrote:
Joe AutoDrill wrote:

Yowza... Not a big problem for me as we have a work around... But I
sure could use a better process... So...

Some of my multiple spindle heads have small needle bearings installed
to support the shafts laterally while they drill vertically... Some of
these are as small as .250" ID up to around .400" ID.

Most are installed in aluminum and steel blind holes with no way of
pushing them out from behind.

Anyone know of a tool or method of removing these without damaging the
housing (esp. aluminum) that they are mounted in?

In some cases, they are double stacked and are of either the same size
or two sizes - larger ID and OD unit on top of a smaller one in a
blind hole below, etc. When stacked, they have thrust bearings
between or a step in the housing if thrust is not an issue.

Any ideas, assistance, etc would be greatly appreciated.
...Especially if it is a tool or manual process rather than EDM, etc.

Regards,
Joe Agro, Jr.

Joe, I used to have a similar problem with brass bushings in pumps, the
bushings would be at the bottom of a blind hole. We used to put about
1/2" of oil(or grease) in the hole and use a piece of round stock that
fil ID of the bushing. After filling the hole and inserting the round
stock we would hit the round stock with a hammer, driving the oil to the
bottom of the hole, which would cause the bushing to lift a little. It
usually took 4 or 5 attempts and the bushing would lift enought that we
could use a modified gear puller to remove the bushing. I don't know if
this would work for you, but it might be worth a try.

That's a great technique I've used many times, but it doesn't work for
needle bearings, unless they have an inner race (rare) and are sealed.
The grease just comes right out (in your face) between the rollers.
One possibilible variation might be to turn a punch to the correct
diameter to fit the ID. Then relieve the diameter from the business end
to double the thickness of the target bearing. Fit a sleeve of some sort
of plastic or silicone that can conform to the needle bearings enough to
seal it.
For the larger bearings, you might even be able to use a tube with an
oversleeve to seal the OD to the needle bearing. Fit a plunger to the ID
and use that to pump the grease.
Beyond that, the only thing I know of is a slidehammer.

Don't know if it's useful to this discussion, but I have seen equipment
with dowels and sealed bearings in blind holes, that have a drilled port
to the backside of the recess. That port is threaded for a grease zerk
for extraction purposes.