[Milsurplus] Dynamotor Lubrication

[Mike Hanz]

John's first method is what I use, Ken.  The bearings are not a 
particularly tight press fit on the shafts, and sometimes slide right 
off.  A bearing tool like the one I made for the command set dynos isn't 
essential - some careful work with a couple of knife blades or small 
jeweler's screwdrivers will get them off, but you need to be careful not 
to nick the commutator edge.  In my experiments with an ultrasonic tank, 
I found it almost impossible to get *all* the old grease and grit out of 
them without removing the bearings, though that will certainly help 
immensely.  I don't honestly know how you could do it with the bearing 
on the dyno - the few times I tried it with an ultrasonic cleaner there 
was still junk left in it on the side facing the commutator when I 
removed the bearing to check effectiveness.  If you have a way of power 
spraying the cleaning fluid through the bearing under pressure, then you 
might have a chance, but it'll be messy.:-)   But of course then you 
will have the problem of getting the new grease to both sides of the 
bearing...heh, heh...

73,
Mike

On 4/1/2011 3:57 PM, J. Forster wrote:
> What I do is either (1) remove the bearings or (2) hold the shaft vertical in a
> small dish of solvent in an ultrasonic. When the grease is largely out, I
> repeat with clean solvent, let it dry, and relube.
>
> You can probably do the same thing without taking the dyno apart, if you
> use a grease solvent that does not attack paint, like rubber cement
> thinner.
> =============
>> Finally getting around to collecting all my DM-32's,DY-8's etc. to check
>> the brushes and lube the bearings.
>>
>>
>> Opening the bearing cap at the end of the shafts reveals a kind of shield
>> over the actual balls themselves. I can pick out the old grease with a
>> toothpick, but can't get between the balls.
>>
>> Question: is this the limit of the access to the bearing? Seems like there
>> could be a lot of crud on the inner side of the bearing that I could be
>> missing.
>>
>> I am flushing the bearing carefully with mineral spirits while keeping the
>> dynamotor shaft horizonatal so as not to let the dilute crud fall into the
>> commutator.
>>
>> Is this the best that can be done? Or is there a secret to getting deeper?