I have been looking for a better On30 coupler, a clunkier HO coupler. In Bruce Metclalf's dissertation on model couplers he mentioned the Accumate Standard coupler series as the right size. I assumed it would be Kadee, Mchenry size, too small with that "pencil neck geek look" skinny shank and that funky knuckle spring. I saw the Accumates on an HO Atlas car at a hobby shop. It was the biggest, klunky-iest HO coupler I had ever seen. The perfect On30 coupler.
A comparison with the current batch of On30 couplers. The Accumate on the left in the top picture, a Kadee #5 in the center and an McHenry/Ez-mate on the right. It is bigger, has a heftier shank and no knuckle spring.
The Bachmann coupler pockets were really bad. They were too narrow and the post is too large. Kadee #5 coupler boxes work much better.
To remove the old box I made a metal plate to gauge the pocket removal. I used an old car weight about a 1/16 inch thick. A slot is cut into the metal to accommodate the pocket.
Styrene shims are glued on the bottom to make the pocket the right height when the coupler is a assembled on the car. The pad is .117 thick with the shims.
Place the guide pad around the coupler pocket. With a fine tooth hobby saw cut off the pocket flush with the plate.
File the pocket base flush with the guide and drill out the original hole to accommodate an #2 wood screw or tap for a #2-56 machine screw.
Mount the Accumate coupler to the car frame with a Kadee #5 coupler box and a #2 wood screw.
Accumate sells an uncoupling tool for a manual uncoupling. The Accumates work better than the other couplers at manual uncoupling. I don't use magnets and the magnetic "glad hand" will be removed from my example.
The Accumates also couple better than either the Kadee or Mchenry.
I think the standard Accumate is a better coupler for On30 than either the Kadee #5 or the McHenry/EZ-mate. It is closer to the right size for most narrow gauge railroads. The Kadee #803, their S scale/On3 coupler is too big. It also performs better in coupling and manual uncoupling.
The cars must be modified to use center shank couplers.