[Spridgets] Rearden metal

Dean Hedin dlh2001 at comcast.net
Sun Dec 16 16:01:35 MST 2012


Almost there...  

Just need to cut those troublesome slots and I'll be home free.

The extra length shaft is sacrificial. It's needed for fixturing
while I cut the slots.  You wouldn't believe the contraption that
is needed to cut those dang slots!

I sure hope I can cut those slots.  Otherwise all the efforts up to 
this point will be for naught.

You can see in the picture the old rotor slots start to wear in "v"
shape.  That's why I'm doing this.  The believe is that the harder
7075 will be more robust with regard to wear.

BTW, the link I posted the other night about all the how-to machining
stuff was no coincidence.  I've had to study up on techniques!

Look at the shine on that 7075.  Isn't it something?  That's right off
the lathe, no polishing or anything.

The original Judson rotor was cast aluminum onto an interlocking shaft. 
I've had to come up with a more modern approach to mounting the rotor
onto the shaft.  

I've cut a 3/4" long machine key on the back side and the two are
interlocked with 1/4" square key.
The shaft hole was reamed to a tight slip fit and I used Locktite 680 shaft
mounting compound.  The machinist at work assures me this will never come
off. 680 is a really strong version of thread locker, designed for things
that are never intended to be disassembled.

Even if it did I'm still covered because the way things are designed the
rotor is pushed against the key as a result of tightening the nut on the
front of the shaft.

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