< Driving Wheel Assembly 3 >
The first and third driving axles are thinned
in their middle parts, especially because
the first axle must be clear the inner main
rod.
The driving wheels are glued on the axle
with Loctite. Immediately the keys are hammered
into the key groove. I used brass block between
the key and hammer to prevent damage.
At that moment I detected the mistake that
I announced last month. The inside crank
of the second axle is 180 degree opposite
from the correct angle...give me a break!
At last I realized the key groove angle is
incorrect. The key should be opposite to
the outer crank pin! I cannot disassemble
the cranked axle because the shafts and the
castings were permanently fixed with pins.
Unwillingly I decided to prepare a complete
new set.
First of all, I have to remove the glued
wheels from the axle. Pulling the wheel with
'Gear puller', the whole job is heated up
with gas torch. Stop the heating when the
axle starts withdrawing, and then pull out
the wheel with gear puller. The photo shows
removed parts. The axle is colored by oxidation.
The shafts and crank castings were machined
and assembled in the same manner as before.
But this time I didn't thin the axle ends.
Spacing of the castings was done with a spacer.
So as to reproduce the phase difference between
left and right key grooves, again I set the
quartering jig up and traced phase difference
of the failed job to new one.
The right hand job is the new one. Note the
difference of key groove angle.
Paint of the wheel was damaged by the heating.
So I removed the paint by thinner and wire
brush, cleaned the wheel with acetone, sprayed
polyurethane paint.
I bought a new paint aerosol for the recovery.
To save the rest of paint aerosol, I painted
the bogie truck. Frame set and other parts
are painted separately and assembled again.
I made a mistake again! When I polish a boss,
I forgot to protect the counter weight with
cloth tape. As a result, paint of the counter
weight was damaged. Once again I bought a
paint aerosol and painted the boss again.
The rest of paint is utilized for the pony
truck and the leaf springs.
The polyurethane spray aerosol has to be
used up within 24 hours after mixture. I
can avoid a waste of paint, managing the
remainder by a digital scale. But it means,
in case of such mistakes, I must prepare
new bottle every time and engage myself in
unexpected paint works.
The wheels were glued onto the axle again.
And then I examined the quartering result.
The axleboxes are piled and glued on a surface
table. The wheel assembly with dummy crankpins
is mounted on it and the backside crankpin
is fixed with a packing of suitable height.
Thus the front crankpin's height is measured
by height gauge. I measured 6 times for each
wheel set (3 times for each side) in rotation.
The average is calculated and compared with
other wheel sets.
Difference between the first and third sets
is 0.08mm, which is permissible. But the
second one is deviated 0.3mm from others.
I guess the recovery process and the difference
of axle diameter caused such large error.
I will prepare an eccentric crankpin for
the second set.