QUESTIONS AND ANSWERS
Fine-tuning Sergent couplers
Q.
I do a lot of detailing and weathering, and Sergent couplers
(1) are the best as far as prototypical detail in HO scale. They
make a big difference in photography. I have now built a small
switching layout and immediately noticed issues with coupling.
The Sergents seem very finicky. Many times the ball will not lift
so I cannot get the knuckle to release, many times the knuckles
don't close when coupling.
– Kevin
A.
A club member uses them and said he has to burnish the cou-
pler faces and back sides of the coupler faces. He also said care-
ful attention to removing the flash is very important. Graphite
lube is a must on all the moving parts.
– Pete
Sergent couplers YouTube video:
Questions, Answers & Tips - 1
1
1: Sergent HO scale
couplers function
like the prototype,
with a ball dropping
in place behind the
knuckle arm to lock
couplers closed.
Graphite lubrication
and careful removal
of casting flash
is vital to smooth
operation.
I have Sergent couplers on my whole fleet, but they are more
time-consuming to assemble and install than more traditional
couplers. Wherever possible, I buy the kit couplers, and I find
they tend to work better than the factory-assembled ones.
When I assemble the couplers, I inspect every casting and
remove even seemingly insignificant flash before assembling
anything. Just to be sure the ball pocket is clear on top, I usu-
ally stick the point of a hobby knife in there and spin it around a
couple of times. Sometimes there is flash in there that is difficult
to see. Next, I apply graphite to the working surfaces of the top
casting, the place the knuckle sits, the ball opening, and any sur-
face the knuckle will slide on or near.
With the top casting all graphited, I assemble the coupler. Once
assembled, I remove it from the jig and glue it together. I have
found the best way to glue them is to use as little as possible, so
little that it flows into the opening by capillary action. If there is
a drop or bead of glue when I am done, I have used too much.
MRH-Sep 2013
