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Old 03-04-2014, 09:45 AM   #29 (permalink)
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Posts: 5,400

Join Date: Nov 2009
Location: Massachusetts

Rons and HeliProz MT both have -18 in stock. I ordered a couple more and now have 6 of those.

The -17 is out everywhere. That one looks like you *might* be able to make one with home shop tools - if you have a good drill press and maybe a small arbor press.
  1. Take your crashed -17, undo the setscrews, and use an arbor press to push the aluminum collar out.
  2. Order the blank that fastflyer linked to ( A 1M 4-Y24024)
  3. Cut off the shank.
  4. Cross drill for the 2 set screws (have to rig up a jig to hold the gear)
  5. Drill out the bore to fit the aluminum collar
  6. Press the old collar into the new gear with your arbor press.
There is some trickiness... you need to be as accurate as possible boring out that center hole so you don't end up with vibes. Also I'm fairly sure that how they made them originally was to press in the collar, and then cross drill and tap. the result is that both the collar and the plastic of the gear is threaded. We cant do that since there will be no way to guarantee that the threads in the plastic will line up with the old collar so either you drill the cross hole oversize and rely on only the collar thread, or we have to find new collar blanks (better option?).

The same process above could be used to make the tail drive spur gear with a 2MYZ1002706 blank.

EDIT: For those of you still trying to stock up - it looks like HeliProz MT still has assembled tail drive transmissions (131-34) and tail cases (131-129) in stock. Pricey but you get the housing, all the gears, shafts and bearings.
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