Friday, March 9, 2018

Free Washers!

I know I've been talking a lot of trash on my first bench grinder (for what a piece of trash it was, honestly, no roller bearings!).  However, history has shown that this blog has been very productive in utilizing every part of that broken grinder for the greater good.  For example, using bits of the housing for bicycle fender and basket brackets, melting the aluminum housing, and prior to that, using it as a sketch pad.  And to top it all off, I'm even still using the original grinding wheel on my new bench grinder, so I'd say that was $3 well spent, right?
After all this time, I'd never gotten around to the rotor.  I recently learned in my casting class that the aluminum part of motor rotors are actually diecasted directly onto the shaft and steel laminations forming a permanent bond (which would explain why they're so difficult to remove!) I wanted to remove the rotor, so I decided I'd try to turn it all the way down on the lathe.
Picture from the bench grinder fan post
What I didn't realize was that the steel laminations were actually round disks which extended radially outward like fan blades, with the aluminum (the non ferromagnetic material) cast in between to fill the remaining space.  I had been under the impression that they were just strips of steel embedded on the outside of the aluminum.  The good news for me: after turning through a good 1/4" of the aluminum/steel mix, I arrived at the bottom of the assembly, which looked like a bunch of serrated washers stacked together.  They separated with ease once there was no more aluminum holding them together.

I figured I could get an even greater $3 worth by turning down the pointy parts and using them as washers!  Already perfectly sized for 3/8" too!  I clamped the stack on the shaft against the chuck with some 3/8"-24 jam nuts, and then turned the outside smooth.
The result: free washers!  Now of course, I didn't go through and de burr the edges as smooth as I'd like, but still almost as good as store-bought quality.
Score 2 for Scrap Alchemy: free washers and free 3/8" rod

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