< Bending Rolls >
Before starting the platework, I decided
to prepare a home made 'bending rolls' which
will be used to bend the cab roof. It is
a typical three rolls type. I designed it
as simple as possible. The effective length
is 375mm and the diameter of rolls is 30mm.
To prepare the pedestals, I gathered three
of narrow BMS bars into a piece by silver
soldering. A brass stud and nuts were used
to fix the bars together, during soldering
operation. After that, the stud was cut out
and filed flush.
Slit in the pedestal, in which the axlebox
will slide up and down, should be truly parallel.
It was trued up by 16mm dia. endmill.
Finished pedestals. The three holes were
drilled and reamed. The top bar is a stay
for push-bolt of the axlebox.
Assembled frames. The base plate has a pair
of narrow steel bars at its bottom, which
will be chucked in a vise, in practice. All
of components were assembled with 6mm dia.
steel bolts.
I obtained suitable gears from a gear supplier.
It was made of silver steel and hardened.
Note they have bushes for set screws.
The rolls are made from a length of 30mm
dia. silver steel. Great labor with a hacksaw
!
The rolls are too fat to go through the lathe
headstock, So I employed 'fixed steady' to
turn the rolls at right end of the lathe
bed. The roll length is limited by the lathe
bed length. Incidentally, turning with 'fixed
steady' can achieve more accurate result
than that with 'three-jaw'.
End of the bar was slightly flattened, so
as to secure the gear with a set screw.
Finished rolls. The thinner one is a driving
shaft of the gear set.
The axlebox was made from a gunmetal round
bar. It was cut, faced, drilled, reamed in
the lathe, then squared by milling. Instead
of flanging, I employ a snap ring to hold
the axlebox in the rolls. Note a short piece
of steel is glued onto the axlebox, which
will protect the gunmetal axlebox from the
steel push-bolt.
The rolls and gears were assembled, then
insert a steel bush into end of the driving
shaft, which hold the operating handle. Now
the machine was completed.
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