< Leaf Spring Set And All >
[Milling Power Feeder]
I made a simple power feeder of the milling
machine with only one axis and constant speed,
utilizing AC 6W small motor with a speed
reduced to 10RPM by a gearhead. It was connected
to X-axle of the milling table with a coupling
sleeve.
The sleeve can slide along the motor axle,
but bound in circular direction by a groove
and a pin. When not in use, you withdraw
the sleeve towards the motor, then a crossing
bar drops between the sleeve and X-axle.
And you can rotate X-axle freely with a handle
at another end of the X-axle.
If you pull up the crossing bar, a coil spring
pushes the sleeve against X-axle. You turn
on the motor, then the sleeve and X-axle
are bound by two pairs of pins and notches,
and X-axle starts rotating.
I also prepared auto-stop function with a
small emergency bottom. A steel bar fixed
on the base pushes the bottom fixed on the
moving stage at desired position. Both the
steel bar and the bottom can be fixed at
any position and direction.
[Truing up of the main frame]
The main frames had a slight warp. It deviated
3mm from the true straight line at middle
of the frames. I designed the chassis assembly
strictly so as to clear 7.5 meter radius
track, so 3mm deviation cannot be ignored.
Therefore I tried to true up the frames.
Mount two steel blocks at both ends of 1
meter long steel bar. Bridge the frame between
the blocks. Then squeeze the frame and the
steel bar together at midpoint of them with
2.5 ton large clamper. I controlled both
squeezing level and deviation change by a
height gauge. Finally I got less than 1mm
deviation by squeezing more than 30mm.
Incidentally, I employ 1 meter steel ruler
as 'straight edge'. You can confirm straightness
of your ruler as follows. Confirm that the
width of the ruler is uniform in any position.
Scribe a long line with one edge of the rule.
Reverse the ruler and fit another edge to
the scribed line.
[Main frame cutting]
I modified design of the main frame. But
it had already laser-cut, so I have to do
additional work by myself. Separating surplus
metal by drilling in array, then I finished
them with files and mills.
Main frame rear end was cut to a half thickness
so as to attach the rear frame. It was a
hard work to cut 6mm depth in large area.
I employed rough-cut end mill and power-feed
for the work.
[Leaf spring set]
It is terrible work to prepare functional
leaf spring for each wheels. Because, for
my engine, it needs 148 of bent plates and
almost of the plates have octagonal profile.
Full scale locomotive has steel leaf spring.
But steel is too strong for scaled down locomotive.
So I employed phosphor bronze plates for
them.
I asked a machining factory to shear a large
phosphor bronze sheet to 12mm width strip,
and to bend them in a desired radius. The
photo shows package of the strips from the
factory.
The strip was cut by a hacksaw,then, so as
to finish in a shape, I made a milling jig
to hold 6 plates in a time. The rotary table
is not for cutting radius, but to rotate
the job at an angle of 45 degrees. After
milling, holes for binding and linkage were
drilled with the same setup.
Finished spring plates. I managed a lot of
plates in different length like that.
The leaf spring holders were made from laser-cut
steel strip. The picture shows a bending
jig with and without job, made from steel
scrap. Note the slit in front face of the
jig, in which once-bent strip is inserted.
Then whole job is clamped in a vise firmly,
and second bending is done. Although the
strip was pre-annealed by a propane torch,
hard hammering was needed to get a sharp
'U' shape.
Assembled leaf spring. From the top, leading
wheel's spring, driving wheel's spring and
trailing wheel's spring. It needs 10 sets
in all. Note the 4th plate from top has half
round notch at each end, so as to clear linkage
shafts.
In the last month, I joined 'Mini-SL Festa
in Fukuchiyama', one of the biggest live
steam meets in Japan. 90 locomotives were
running at 700 meters endless track.
Also in this month, I joined a meet in Akubi Lightweight Railway, a garden railway produced by a famous Japanese
mystery writer Hiroshi Mori. The loco I drive
is 'Shay' built by a Japanese model engineer
Yoshinori Kiuchi.