Modification for couplers on P2K chassis gp7/9 old version!

[belair]

Can anyone tell me if they have modified the old version of the proto gp7/9 chassis to mount couplers to the sill portion. If so, will the sill hold up to pulling capacity?


Any ideas would be appreciated!


Thanks,
Brock Joubarne

[beentherecnthat]

What I have done with them (and some Athearn blue box) is to create a styrene pad behind the pilot and up to the level of the coupler opening. Make sure it doesn't extend back too far so the chassis still fits. You can use styrene strip and sheet material and build it up until it is flush with the coupler opening.
Take the chassis/frame and drill through the dimple in the coupler pad with a tap drill for a 2-56 screw (#50 drill). Put the frame in the shell and run the drill through the new hole in the coupler pad to mark a spot on the new styrene mount. Remove the frame and drill, then tap the styrene par for a 2-56 screw. Make sure not to drill right up through the walkway. Then open up the hole in the frame coupler pad for 2-56 clearance (#43 drill). Now you can put the frame in the shell, insert the coupler assembly through the pilot opening and attach everything with a brass 2-56 screw.

[belair]

So my understanding is that you did not remove the lower under hanging mount for the original configuration? By any chance do you have a picture or two?

Thanx for all the help! I have three chassis's that I would like to upgrade!


Regards,
Brock Joubarne

[m a y o r 79]

I have an older Proto SD7, back from when Life Like still made them (well, actually converted to an SD10 but anyway), and the frame bracket for the coupler mount broke off on one end. I just built up a block of styrene to replace it and re-mounted the coupler pocket to it. Ends up pretty solid, just make sure you get a good glue bond to the frame. Roughing up the metal seems to help everything stick better.

[belair]

Thanks for the input! I will try your method...


Regards,
Brock Joubarne

[spike]

I try to kill two birds. I make a styrene block, attached on the underside of the walkway, but have the layers nearest the coupler pocket go over the frame. This gives slightly more support, and helps keep the frame on. Just don't glue these layers, or the shell won't come off. The tapped threads keep these in place. Just watch for interference with truck swivel.

[belair]

I am going with your idea!


Brock

[m a y o r 79]

I've got a Proto SD7, original release, that has the old Athearn clone coupler mounts. you can fairly easily trim a Kadee No 5 coupler box and mount it to the top of the coupler mounting pad on the frame. Tap it for a 2-56 screw and you shouldn't have any problems if your worrying about a styrene pad holding up. This way the weight of the train is transferred directly to the frame thru the screw and you're not relying on glue joints.

Gluing up a styrene block should work fine though unless you're pulling 100+ car trains around your layout.