Back when I was in HO scale, I was highly interested in the scale appearance and operation of Sergent Engineering couplers. Even after converting to N, I haven’t lost my desire for replacing oversized couplers. Fortunately, I found that a solution in N does exist, made by Micro Trains, no less. However, I immediately ran into a problem with them; they require broad curves, as there is very little side to side motion in the design, causing derailments on tighter turns.

I eventually came across a forum post by wcfn100 on therailwire.net, who was making scale draft gear that’s compatible with these couplers. The specific post was detailing how to modify the couplers to fit in his draft gear. I’m repeating the technique here to hopefully make this easier to find, by giving it a discreet web page, rather than it being buried in a forum thread.

Start off as usual by removing the pieces from the sprue.

On the non-knuckle half, make a cut in the ring right next to the shank, on the opposite side from the centering/closure finger.

Next, cut off the centering/closure finger on both halves.

The provided 00-90 mounting screws are the same size as the hole, so assemble the halves on one and hold the knuckle closed with reverse action tweezers.

Take a soldering iron with a fine tip, medium high heat, and touch right behind the cut we made, welding the two halves together. Don’t hold it for too long, just a brief touch should be sufficient.

The location of the weld. Be sure not to accidentally weld in front of the cut, up on the shank; this will make the coupler very difficult to operate.

Now simply remove the screw, and it’s ready to assemble.

All done! You now have true scale couplers that can freely swing in their pockets, allowing negotiation of much tighter turns than before. Now, this does mean that there is no automatic centering force, so you’ll have to manually align them when coupling. This is an acceptable sacrifice in my opinion, as real couplers have no such feature; and even in HO scale, Sergent Engineering couplers also lack any centering.

There’s still improvements I’d like to make; the force needed to couple can still be rather high, especially for the short shank variety. And despite what I just said, I’d also like to see if I can Frankenstein some centering springs for these. But for now I’m satisfied with these, and think it’s worth making these the standard on my layout.

In the future I’ll cover how I achieved some installations that required unique solutions.