On Wed, 15 Jul 2015 15:40:15 -0500, Tim Wescott
wrote:

On Wed, 15 Jul 2015 07:50:48 -0500, David R. Birch wrote:

On 7/14/2015 7:49 PM, Tim Wescott wrote:
I made a replacement shaft for an electric model airplane motor. My
wife bent the old one as part of the learning process (she's learning
control line. You cannot fly ten dumb thumbs high with a control line
plane -- you're always one or two mistakes away from disaster).

So, during the better part of an hour's worth of work, I cut a 3mm rod
to length, made a 20-mil wide groove cutter, cut a groove, pressed out
the old shaft, and pressed in the new one.

Making the cutter on my bench grinder took most of the time.

The best part is -- I saved $8.50! $7.40 for the motor, and $1.10 for
a replacement shaft! For just an hour's work!

If I were doing this, it takes only a bit more time to make 2 or 3 for
the next accidents.

Most of the time was spent making the tool, and that's done.

We bent another one today, so I have my evening's entertainment laid out.

(She's learning control line, where basically you don't crash at all or
you land on the propeller. Infernal combustion engines tend to have much
stouter crankshafts than 'lectric, which is why those little Cox plastic
planes ever survived long enough for a second attempt).

My solution to teaching people to fly control-line planes was to teach
tem on 1/2-A planes in tall grass. It saved props and motors. g

--
Ed Huntress