<snip>
:
: > Some form of alignment jig is essential if you are
: > fitting sliding hornblocks that require you to cut slots
: > in the chassis.
:
:
: Suspect you are over my knowledge/experience too.
: Havent reached the level of sliding hornblocks.
:
But it's as relevant to 1/8" 'top-hat' bearings and all types of
chassis (even the old style castings found with some kits) as it is to
sliding horns or the Flexichas system, what this way of aligning the
axles does is ensure that they ARE in alignment - by using the one
item that can't easily be adjusted, even a few thousandths of an inch
discrepancy can cause binding of the coupling rods or more slop that
the you know what up a shirt sleeve, but has to be correct - it's all
to easy to build a chassis that requires so much metal to be reamed
from the coupling rods that not only are they grossly sloppy on the
crank pins but their structural integrity is compromised. As I pointed
out before, the most critical stage in any build is making sure that
both sets of coupling rods have
*exactly* the same pin centres [1] and
that the main axle bearings match those centres, the rest of the
chassis can be quite some way out of true and the loco will still run
down the track looking like a mechanical master rather than a duck...
It's actually easier to adjust the fit of the chassis bearings before
they are fixed (soldered) to the chassis frames/block that try to
adjust the 'fit' of the coupling rods at the wheel quartering stage -
many 'wheel quarting problems' are nothing what so ever to do with the
wheels but the fact that the axle centres do not match the coupling
rod centres!
[1]
o=====o-------o
CORRECT
o=====o-------o
Compared to;
o=====O-------0
WRONG!
O=====o-------o
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