[ARC5] Bearings for DM-28 dynamotors

[Kenneth G. Gordon]

On 25 Nov 2014 at 16:30, Clare Owens wrote:

> I found an ebay seller (tybennet27) who has 36KT bearings NOS for $5.00
> each.  I ordered some and he merged the shipping so the bunch were just
> shipped for $3.00.
> 
> I'm a little surprised that the WW II bearings were metric - or maybe
> bearings "always" have been metric??

Well, as I remember it, the bearings aren't "metric" in that sense, BUT 
bearings have always been made in many, many sizes, some of them pretty 
weird. I have never had any trouble at all finding a replacement bearing 
by taking the old one to a machinist-friend of mine and having him 
measure it up properly. He told me once that no bearing is irreplacable.
 
> Now I'll learn how to remove them or rather how hard it is to remove them
> without too much collateral damage :-)  Reading about it is one thing,
> doing it another.  I really do (usually) enjoy trying new things...

Mike Hanz' site has a section devoted to the rebuilding of dynamotors, 
including replacement of the bearings. Mike wrote an article on this 
subject for Electric Radio Magazine a long time ago. He rebuilt a totally 
rusted-to-crap dynamotor into what looked to me like NEW condition.

Based on the "before" photo, it was nothing but a ball of rust.  I would 
have consigned the wreck to the junk metal pile. Obviously, I was 
completely wrong.

Ken W7EKB