The Bucking Magnet Motor

[broli]

This is what should define this forum, great progress. It's rare to see the evolution of an idea beyond words on this forum but this thread is a good example of it.

As for the build, is there a reason you went for aluminum and not say plexiglass or so.

[z.monkey]

As for the build, is there a reason you went for aluminum and not say plexiglass or so.

Lexan (Plexiglass) cracks easy when you drill it.  A Lexan panel would have to be laser milled, and you can't make threads with a laser.  Wood is too soft, can't make the dimensional tolerances.  I need light weight and rigid which aluminum does well.  Also this is not general aluminum, its an alloy designed for use in aircraft.  This alloy (AMS4027) exceptionally light and rigid.  It has traces of Magnesium, Silicon, Copper, and Chromium in it.  So, in the end having rigid pieces and maintaining dimensional tolerances is my motivation for using this particular alloy.  It wouldn't make a very good motor if it was all floppy, and prone to cracking.  Iron (Steel) is another exceptionally rigid material, but it is ferrous, and I didn't want to throw another magnetic variable in there...

Another note on Vertical Milling.  The cross slide table that I am using is pretty floppy.  It doesn't do side cutting very well, lots of buffeting due to slop in the cross slides.  So, I had to resort to using Vertical Miliing, which is similar to drilling, except we're using a mill instead of a drill, and we have the precision positioning capability of the cross slide table.  I am positioning the table, then milling a hole.  Then I move the table about 80 mils, and cut the next hole which overlaps the first hole, cutting the webs that would normally separate two side by side holes.  You can't do that with a drill bit, held by hand.  Basically I have realized that I need a way better table.  Looking at a Palmgren table now...

http://www.palmgren.com/compound-milling-table-18-in-mtc18/

With an actual Milling Table I can do way mo-betta side cutting, which is a lot faster.  It all is dependent on the stability of the mount.  If your mount is floppy then you are going to get a lot of buffeting which makes butt ugly cuts.  With a rock solid mount all the energy of the mill is exerted on the cut, which makes nice clean, fine cuts.  It makes the process a lot cleaner, and faster, albeit you have to spend mo bux on the tool...

Buying high quality tools is always worth it in the end.  All the frustration that I have suffered with the current cross slide table could have been avoided if I had bought a better table in the beginning.  Granted this table is about 4 times as expensive.  That more than makes up for having to redesign the current table, and all the angst associated with it...

[z.monkey]

Just finished the rough cut on the stator disk.  Now I need to clean it up, drill the center hole out to 3/8" for the shaft arbor, and drill some weight relief holes...

[z.monkey]

OK, good progress this week.  The UABMM has been fabricated.  I got the stator cleaned up and all the holes punched.  When I was finally done the stator was very warm, and felt soothing on my tired hands.  I was able to make all the cuts amazingly close to the markings on this one.  Maximum finished tolerance on the cants is conservatively close at around +/- 10 mils.  I'll spend a couple of days measuring, and verifying, but I am sure this is the most precise piece of metal (stator disk) I have ever fabricated.  Then I fitted everything together, and it is totally sweet...

Looks like I need to get some magnets on order...

Woot!~>  \m/___(0.o)___\m/

[broli]

Congrats, I bet all the crap you endured was worth it. Irregardless of working or not, you have gained a huge amount of experience and knowledge that no armchair could ever give  .