HO shay coupler conversion

Hi, I recently converted a bachmann HO shay to Kadee #158 wisker couplers.The problem is the coupler pocket is too shallow and the centre protusion is to large for the hole in the coupler.I was able to file the coupler shank thinner and bore out the centre hole in the coupler just a hair and it works great,BUT because the coupler is metal and the shay is a split frame, you could have a short. the shay comes with plastic couplers. so I would like convert my shay so the couplers would be insulated from the frame. the only way I can see to do this, is to remove existing coupler box by filing it off and mounting Kadee plastic coupler box. I was wondering if you have any suggestions.
Thanks

A trip to the Kadee site indicates that you are not using the recommended wisker coupler. The recommended coupler is the #148. Otherwise the #5 or #58 couplers for this engine.

He’d have the same problem. The shanks on the #148 and #158 are identical - only difference is the head. There are plastic-shanked equivalent couplers in the Kadee line, though they aren’t “whisker” types. I’m not sure what the numbers are, but it shouldn’t be too hard to find out.

Have you considered using McHenry couplers? They’re plastic, so you won’t have to worry about them conducting electricity.

That;s probably what;s on there. You might find a insulating paint, and coat the coupler AND the inside of the box. It doesn;t matter if the inside of the coupler box ends up ACK MY EYES pink, it;s inside and no one would see it.