TIPS & TECHNIQUES

Kadee Couplers for the USA F3


    The USA knuckle coupler is not compatible with other brands of
couplers.  Because of this, I change my USA engines to Kadee couplers
and shorten the spacing at the same time.
    I got smart on this conversion, and e-mailed Kadee for their
instructions to make the conversion.   Kadees fisrt statement in their
instructions is  that "this is a challenging conversion".  Use #831
couplers for pedestal  mounting.  Remove the coupler mounting pedestal.
On the rear of the A and for the B take the assembled coupler and place
on the pivoting arm of the pedestal.  The pivot arm should fit evenly
into the slot of the 831's draft gear box.  Secure with original screw.
Make two L shaped pieces of sheet metal approx. 1/16" thick.
Dimensions: 1/4 " wide,1" high, and the L piece 5/16" long. Drill a hole
in the L portion.  These are screwed in place with the pedestal mounting
screws on each side of the coupler.  What this does is prevent the
coupler from pivoting too far when pushing cars, which would either
cause problems with the diaphragms and/or derail the following car.
    To mount the coupler to the pilot pedestal.  First remove the dummy
coupler and pedestal.  Fill the slot in the draft gear box with a strip
of .080 plastic shim stock to make a flat surface.  Make this shim about
.100" longer than the slot of the draft gear box and drill a tiny hole
in it for the wire centering spring.  Mark the shim through the rear
hole of the draft gear and drill a hole for a 6-32 screw.  Slip the
screw through the bottom of the pedestal and thread the shim over the
screw down the top of the pedestal.  Re-attach the pedestal to the floor
of the locomotive.  Slip the coupler  through the pilot slot and over
the screw. Secure the coupler with a 6-32 hex nut.  Leave this a little
loose so the wire centering spring will keep the coupler straight.
    With the pedestal mount on all units, the locomotive will negotiate
2 foot radius curves with the coupler in coupled or delayed position.
If you run a trailing A unit, the pilot will need a 2.5 foot radius
minimum.
   To body mount couplers, you need to build mount platforms 1 25/64"
long,  3/64"  wide and 35/64" tall.   (I can see Kadee coming out with a
machined block already drilled and with the proper screws in the future.)
Your mount needs to  be drilled for the original mounting holes in the body.
You will have to countersink the holes to use the original screws.  Secure the
mounting platforms to the body.  Shorten the draft gear box rear by
13/64" so it will clear the trucks. You do not need  to trim the pilot coupler.
  Place the coupler on the platform and mark the mounting hole
  location.  Drill the holes and mount the couplers.
    The body mount will allow the locomotives to negotiate a 4 foot
radius curve when coupled but not in the delayed position.  If you notch
out the sides of the draft gear  box it will negotiate a 2.5 radius curve.
Also be aware that the diaphragms will slide past each other but snap
back in place on  S curves or turnouts.  This will cause a great deal
of wear on the diaphragms.
   If you want this info, e-mail www.kadee.com and they will
"snail-mail" their information with diagrams.
They will do this for any conversion you are trying to do.
   To couple your F3 units at a more prototypical distance, you will
have to modify the mounts to pull the couplers closer to the body.  If
you do this, you will have to remove one rubber diaphragm between units,
since two diaphragms between units makes the coupling distance too great
to look prototypical.
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