Hey, i’ve been searching around here and haven’t been able to find anything. I just got an Athearn SD9, and I put self-centering Kadee’s on them, but they sag a little bit. I’m not sure exactly what I should do to shim them up; is styrene the only way to go? or would I be able to get away with cardstock or something? i don’t have a caliper, so should I just bring the engine to the LHS and test-fit the styrene they have there?
Kadee makes shims for just this purpose. Check with you LHS, if they have the couplers they are likely to have the shims as well. Get a coupler height guage as well, it’s worth the money.
Mark Gosdin
When you say “sag,” are you talking about the coupler being able to move vertically in the coupler box, or the coupler is actually too low as measured by the gauge? If it’s too low, you’ll need an offset head coupler, what Kadee calls an underset head, like the number 47
http://www.kadee.com/htmbord/page347.htm
If this raises it too much, then you’ll need to shim it back down, and Kadee has the shims made to fit between the box and coupler mount on the loco
http://www.kadee.com/htmbord/page145.htm
If the sag is caused by the coupler being able to move vertically in the box, then you need to do a small modification to the box. With a fine file, make a couple of passes over the end of the coupler pivot point on the lid to shorten it slightly. Trim off the back edge and side screw holes to allow the cover to slip a bit deeper into the box. You may also need to shave a bit off the top edge of the box part to mount it.
As many (including me) have said in coupler question threads, use the Kadee gauge for checking the coupler and trip pin height and adjust as needed. The Kadee conversion list on their website is a guideline and not gospel. The gauge should always be the final word for height.
the sag is caused by the coupler being able to move vertically, as you said. the weight of the coupler head causes it to sag down at a slight angle; otherwise its at the proper height