I found a Makita die grinder at the dump. It had a bad bearing, but I
had one in my collection (I just love when it works that way!).

The question is about some grooves in the case & matching ones in the
spindle:
http://home.comcast.net/~bobengelhar...derGrooves.jpg

At disassembly they had gunk in them, I assume some kind of very old
grease. I also assume that the purpose is to keep dust out - these are
not bearing surfaces.

Does that sound right & ,if so, what grease should I use in re-assembly?

Thanks,
Bob

Bob Engelhardt wrote:
I found a Makita die grinder at the dump. It had a bad bearing, but I
had one in my collection (I just love when it works that way!).

The question is about some grooves in the case & matching ones in the
spindle:
http://home.comcast.net/~bobengelhar...derGrooves.jpg

At disassembly they had gunk in them, I assume some kind of very old
grease. I also assume that the purpose is to keep dust out - these
are not bearing surfaces.

Does that sound right & ,if so, what grease should I use in
re-assembly?
Thanks,
Bob
Those look a lot like grooves (in the case) for a labyrinth seal - I say
that because of the shape . Can you google the model number and get the
'sploded drawings / parts list ? I'm thinking some kind of rubber seal that
protrudes into the grooves in the spindle , that gunk might have been the
remnants of the seal mixed with the remnants of grease .
--
Snag
sometimes ya gotta
shovel manure
to pay the bills

Terry Coombs wrote:
Those look a lot like grooves (in the case) for a labyrinth seal - I say
that because of the shape .

They are weird, aren't they? Actually dovetails!

Can you google the model number and get the
'sploded drawings / parts list ? I'm thinking some kind of rubber seal that
protrudes into the grooves in the spindle , ...

Yeah, I did that (great minds ...) - no parts shown there.

Thanks,
Bob

On Wed, 03 Dec 2008 20:08:17 -0500, Bob Engelhardt
wrote:



Yeah, I did that (great minds ...) - no parts shown there.

Didja try here?
http://www.toolpartsdirect.com/makita/makita-12.html

--
Ned Simmons

Ned Simmons wrote:
On Wed, 03 Dec 2008 20:08:17 -0500, Bob Engelhardt
wrote:


Yeah, I did that (great minds ...) - no parts shown there.

Didja try here?
http://www.toolpartsdirect.com/makita/makita-12.html


Oops, by "no parts shown there", I meant the parts diagram that I found
did not show a gasket/seal part for the spindle. Actually, it was
toolpartsdirect where I found the diagram.

Bob

The shape of the grooves sure seems peculiar. Maybe washers of some soft
material that had a slight lip around the circumference were intended to
sort-of pop into those grooves.
It looks as though only the ends of the grooves have the dovetail shape
(nearest the case-half parting line).

I'd probably situate a thin metal washer (resistant to grinding sparks) at
the outer location, followed by a felt washer in the space behind it, maybe
followed by another hard washer in one of the other grooves to loosely
constrain the wool felt.
Small clearances should eliminate any friction or heat being generated
during use.

Another felt washer adjacent to the bearing may catch any moving dust,
preventing it from getting into the bearing assembly (even shielded ball
bearings aren't dust-proof, and dust buildup will absorb the lube out of
them). A drop or two of oil on the felt near the bearing may prevent the dry
felt from wicking the lubricant out of the bearing.

It would be hard not to like the concept of free tools.

WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Bob Engelhardt" wrote in message
...
I found a Makita die grinder at the dump. It had a bad bearing, but I had
one in my collection (I just love when it works that way!).

The question is about some grooves in the case & matching ones in the
spindle:
http://home.comcast.net/~bobengelhar...derGrooves.jpg

At disassembly they had gunk in them, I assume some kind of very old
grease. I also assume that the purpose is to keep dust out - these are
not bearing surfaces.

Does that sound right & ,if so, what grease should I use in re-assembly?

Thanks,
Bob

On Wed, 3 Dec 2008 17:49:01 -0600, the infamous "Terry Coombs"
scrawled the following:

Bob Engelhardt wrote:
I found a Makita die grinder at the dump. It had a bad bearing, but I
had one in my collection (I just love when it works that way!).

The question is about some grooves in the case & matching ones in the
spindle:
http://home.comcast.net/~bobengelhar...derGrooves.jpg

At disassembly they had gunk in them, I assume some kind of very old
grease. I also assume that the purpose is to keep dust out - these
are not bearing surfaces.

Does that sound right & ,if so, what grease should I use in
re-assembly?
Thanks,
Bob
Those look a lot like grooves (in the case) for a labyrinth seal - I say
that because of the shape . Can you google the model number and get the
'sploded drawings / parts list ? I'm thinking some kind of rubber seal that
protrudes into the grooves in the spindle , that gunk might have been the
remnants of the seal mixed with the remnants of grease .

I'm with you, Terry. The dovies are at the mating surfaces and it
makes me wonder if that's just built-up gunk, or perhaps compression
of the seals at that point, with grease making up that apparent
dovetail look.

--
Smell is a potent wizard that transports you across
thousands of miles and all the years you have lived.
-- Helen Keller

There's more to the story. I already had a Makita die grinder exactly
like the one that I found. I didn't want to take it apart 'cause it can
be a pain to get back together & 'cause I expected that it would just
have the same grease in the grooves. Which wouldn't help me know what
kind of grease it was.

But your responses got me to wondering whether there was something other
than grease there. So, I took the first one apart and found ...
nothing! There was not even grease - the grooves were very nice & clean.

I've had this grinder apart before & it's theoretically possible that I
had removed whatever was in there, but I doubt it. And the parts
diagram doesn't show anything.

So, the question's not answered, but I don't care - I'm going to put
them back together and use them.

Thanks for the replies,
Bob