The drive set used in "Betsy Ann" is from Hobby Lobby. This
set appears to be imported from England. It has 3 mm. shafts.
Cost $14.00.  Includes 1.5 -3 V. motor. Several gears, a
collar, two 3 mm shafts, and two pillow blocks. Nicely made
and versatile.



The gears seem rugged enough to do the job but the 3v. motor
is deficient.  This 1.5-3 V. motor won't cut it. I ran it a
few seconds on a 7 cell pack 8.4 V. It screeched, emitted a
hot odor, it still works, but it seemed obvious this is not
enough motor for our needs.

I replaced the 3 V motor with a 12v automotive servo motor.
This was made by H.K. Johnson for automotive servo
applications such as heater ducts. This is a Speed 400 sized
motor and any good Speed 400 motor should work. (A Speed 280
might work also and is of higher quality than the one
supplied).

Modify the plastic pillow block for the Speed 400 motor by
carefully cutting away plastic to the embossed line on left
side motor mount with a #11 Exacto blade.  Position the motor
outside pillow block assembly so the screw holes line up and
mark the location for a flat on one side of motor can to
clear the lay shaft.  Keep metal filings out of motor with
masking tape.  File a flat on the motor can to clear the lay
shaft.

After three trial runs the following configuration was found
to work very well. The first tests with the entire
mechanism assembled quickly showed the inadequcy of the
pressed-on gear to output shaft connection. It spun free!
A means of securing this gear to the output shaft had to be
found.

A small disc was made from circuit board material (copper
clad FRP) that was slightly smaller than the orange output
gear.  A hole was drilled in the center for the 1/8" steel
output shaft, a Dubro 1/8 inch wheel collar was soldered to
this disc while a shaft was inserted to provide centering.
After this was cool, the orange output gear was placed on the
shaft and run up to the FRP disc, two holes were marked on
the disc directly from the gear holes. These two holes were
carefully drilled and brass rod soldered through these holes
to match the holes in the gear. In order to get the gear to
run as true as posible a simple assembly jig was made. On a
drill press a 1/8 inch hole was drilled into a flat piece of
wood.  A piece of 1/8" steel rod is placed into this hole.
The makes a very perpendicular jig.  The orange driven gear
is placed onto the shaft and run down to the wood block.  The
custom made collar is epoxied to the orange gear with the
brass gear drivers inset into the gear holes. The set screw
should be tightened before the glue cures.  The collar may
not run true on the shaft, but the gear will!

The first trial run resulted in galling of the first
reduction gear so it was dissassemble and small steel washes
placed between the gears, this worked but exhibited tooth
jumping with associated clacking, cracking noises.  With the
gears set outside the pillow block assembly as supplied the
shaft ends are allowed to "float", resulting in noisy, tooth
jumping and galling on the outermost gears due to torque
build up on final gear.  This sounded terrible but no serious
damage to the gears resulted, amazing! Continued operation
would have undoubtly resulted in damage to the gears.



The final configuration can be described as follows; the
motor is moved outside the box (good grief, Charlie Brown!)
The gears are all moved into the pillow block box, this
stabilizes the ends of the gear shafts at each end of the
shaft carrying the gears, thus preventing tooth jumping by
stabilizing shaft spacing at each end.

The final setup gives good sound operation. smooth wheel
start up with no clacking, and low motor temperature. This
configuration was not directly obvious, but results in a
durable low cost transmission.

A longer shaft must be used for the output shaft to span the
width of the paddlewheel.  Standard 1/8" rod will work only
in the output shaft position. The 3 mm. shaft should be used
for the layshaft. However 1/8" rod can be used for the output
shaft if a green gear is drilled and the pillow block holes
are enlarged.

The output shaft should be long enough to span the wheel and
provide for the two crank arms and two end support bearings.

The ends of the output shaft will be carried in brass
tube bearings at their outermost ends, the working ends, to
stabilize them in high torque situations or higher speeds.

Place the two pillow blocks on the motor mount. Insert
the output shaft  through the side of the boat, into the
pillow left side place a drilled green gear(reduction gear)
onto shaft, Place green reduction gear on lay shaft, pass
output shaft through orange driven gear, then right side
pillow, and out opposite side of boat.

it might be feasible to drill the pillow block assembly for
replaceable brass bushings if desired, later on these could
be replaced with aluminum pillows with ball bearings for the
ultimate gear box.

It would be nice to have a source for American sized gears to
fit 1/8" rod, but the plastic ones can be drilled with an
1/8" drill without damaging the gear teeth .


Cost:
     Gear box and motor   $14.00
     Speed 400 12 v. motor  8.50
     Steel rod               .80
     Threaded rod            .80
     Brass tube              .80
                           24.90

Under 25 Bucks!