Dia. Mag. Alternator

[z.monkey]

I sliced a one inch section from the aluminum round stock.
Got nicely squared up, and marked up, and sank the shaft hole.
Typically you would want to do this on a lathe, because you
want a shaft to be dead nuts center.  Well, I ain't got a lathe,
so approximated as well as I could with the drill press.  The
runout is about 20 to 30 mils,  which is not great.  I haven't
measured it precisely yet, tho...

Cutting a 1.75 inch piece of bar stock with a hack saw was
super, extra fun too...

[z.monkey]

That first rotor (left) was too wobbly, so I made a couple more.
This time I went to a friends machine shop and used a
lathe to cut the center hole.  No more wobbles.  I also
changed the position and size of the peripheral holes.
They reduce the weight and add ventilation through
the rotor.  I am going to add a small fan on one side of
the rotor to pump air through the rotor for cooling.
Don't want my fancy Neo Mags overheating...

[z.monkey]

Spotting...

I have had a lot of trouble getting this concept...

X marks the spot.  Got to hit it perfect...

All the accuracy hangs on this event.  I've had
a crash course in spotting over this week.  Yeah,
uh, gotta have the right tools.  A spotting drill,
a short, stubby, sharp angled drill/mill can help
you hit those X's with zeal...

Also beware of cheap center punches.  Use a
hardened punch with an angle that matches
your Drill/mill.  Then the dimensional tolerances
can be happy...

[z.monkey]

Got the stack spotted.  The first picture has drills in the 1/4 inch holes to show
parallelism.  Then I bored out the center holes to 1/2 inch individually.  The
stack also pictured there has all four plates on it.  I'll only cut two at a time.
First I'll cut the wire form plates, and then the bearing plates.

This time I am using a 1/2 inch center post in the cutting process.  Same as before
where I'll make a special post I can jam into the table, and that becomes the
fourth axis in the process.

[z.monkey]

Yesterday I ordered some more clamping accessories for the Palmgren
table.  The corner bolts on DiaMag8 are 1/4 inch, and the smallest clamping
studs that I have are 3/8 inch.  Also the smallest hole in the T-Slot Nuts
is 3/8".  I can get T-Slot Nuts that have 1/4 inch nuts, but they are too narrow
for the Palmgren table.  So I bought some threaded inserts that are 3/8-16
outside threads and 1/4-20 inside threads to achieve the goal of having
1/4 inch clamping studs.  Should have those today, and then I can start
cutting the DiaMag8 plates.

In the meanwhile I prepared the Music Wire shafts for the Rotors.  Music
Wire is an extremely hard carbon steel used for shafts.  I had to use a
Tungsten Carbide Grit Saw to cut it.  I mounted the Rotors on the Shafts
with an Interference Fit.  The hole in the Rotor is 0.250 inches and the
Shaft is 0.251 inches.  I ground the Shaft slightly, like 0.0005 inches, and press
fit the Shaft on the Rotor.  That means I held the Rotor in top of the
vise, and tapped the Shaft into the desired position with the Blacksmith
Hammer.  Both Shafts fit well, thoroughly lodged in the Rotors, although
one was slightly easier to mount, slightly smaller shaft.  This way we
don't mess up the balance with a hole and a set screw.  Also no set
screw to come loose and get lost, and no hole play tolerances.  The
Shaft and the Rotor are basically a single piece now.

I was thinking about Temperature Mounting the Rotor and Bearings on
the shaft, but found out that I can't put the sealed bearings in a hot
oil bath (300 degree Fahrenheit Oil) without damaging the seals.  In a
Thermal Mounting Process you would cryogenically freeze the inner part
to negative 300 degrees Fahrenheit and heat the outer part to positive
300 degrees Fahrenheit, and then put them together.  As the differential
temperatures balance the inner part expands and the outer part shrinks,
leaving a tight interference fit between the parts.  I did something similar
but with mechanical force, and not temperature, but the result is the
same.  And, no I didn't mushroom the end of the shaft hitting it with the
Blacksmith Hammer.  The Music Wire Shaft is much harder than the
Blacksmith Hammer.  There are actually dents in the face of the Blacksmith
Hammer now.

So, after getting the Shafts mounted I needed to make some spacers to
act as standoffs for the Bearings.  They are 1/4 inch inside diameter
Aluminum Tubes, 3/8 inch outside diameter, cut to 0.750 inches long.
They fit between the Rotor and the Bearings to provide spacing for
the windings.  Then the Bearings are also interference fitted to the Shaft.
The very last thing to do to the Rotating Assembly is to mount the
Magnet Arc Segments, which I'll do with some Industrial Epoxy.

Also there was the Center Stud I needed to fabricate.  This is a non-standard
method which I am using to get around buying more tools at the moment.
I cut a 3 inch long piece of 1/2-13 threaded rod, a little longer than what
is needed.  Then I ground down about a 1/2 inch of threads on one end in
order for the Center Stud to be able to pass thorough the end of the
T-Slot Nut.  Then it can be jammed into the table to act as the Forth Axis.