Adventures in prototypical True-Scale coupler pockets.

[wcfn100]

My edu-guess is M.E. weathered rail on Central Valley tie strips.

Yes.

Jason

[bbussey]

I'm printing in FXD.  I'm not sure of the strength of the pocket.  I just ordered a bunch, when they get here and I get one installed, I can try and do some sort of test.

You should be fine due to the small size of the part.  I've FXD-printed MTL coupler pockets for the Fleischmann RC-2/RC-4 (future AEM-7) and the Kato GG1, as well as replicated the X58 pocket, and they've all held up extremely well.

[Dave Schneider]

Very nice work Jason. That looks really good.

Best wishes, Dave

[C855B]

New info on fitting to the ore car:





Knowing full-well that CA isn't going to bond to MTL's Delrin, I used it nonetheless to show where the mounting height would be if the stock pocket was adhered directly to the cutaway. Looks to be about 0.010" low. A conversion would have to be negative, relatively.

Let me fool around with this. My inclination is to do a thinner lid replacement for the stock short shank box, trimming the nubs on the box flush, and adding mounting "wings". The stock lid is 0.033" thick, so whatever we do will have to be 0.023" or so. FWIW, I'm not real concerned about coupler swing with these shorty cars that generally run as a unit train.

I will say the TSC looks great on these cars.

[wcfn100]

So after playing around with these, it looks like the plan is to come up with 3 standard pockets depending on the car.  What I need is some real world testing I can set up with the little bit of Unitrack I have left since I don't have a layout.  The alternative is to go invade Dave's basement. 

For my personal use, I just need cars to negotiate a 15" radius without an easement and a #7 crossover (but that should work if the first thing works).  I already know that cars over 50' have problems with 15" radius 'S' curves with no straight between and that my current pockets won't handle MTL heavyweights on a 15" radius at all especially those with the kingpin towards the center.

For me the biggest challenge will be to get 85'-89' flats around a 15" radius.  I don't know if that's reasonable, but it's the goal I'm setting.  I'm also very interested in what happens when backing long cuts of cars with pockets that give a lot of swing.

For anyone who's been interested in this project, what are your expectations or requirements?

Jason

[Sokramiketes]

I think where you're headed is a good start.  I've started throwing them on various steam era equipment, using the MTL box, just to get some operating experience going.  The process has reminded me how far away we are from a standardized solution.  The NYC steel boxcars from BLI are a nightmare, as they have cast metal boxes attached to the underframe.  Some of the equipment I've used the 1015 standard couplers on was easy to swap out, but it seems like the height isn't right.  I need to pick a standard coupler height.  And being a 1015 box, that coupler screw still ends up right over an axle on anything that has the bolsters in the right location.

We need a standard underframe that has bolster height and couple mounting pad heights fixed, and plastic underframe detail added. 

Oh, and I'm cutting off the strange upturn on the end of the air hose part, and smushing on a new glad hand with a pair of pliers.  They look better without the strange rise. 

[wcfn100]

@C855B, here the coupler pocket I'm going to send that fits the Atlas ore car.  Turns out the car I was using initially wasn't Atlas.





The challenge is that there's not place to screw to the body.  I think there's enough surface area to just use glue, but I also provided a couple holes that could be used to mount some .030" styrene posts into the shell and then maybe spot melted on the coupler.  If this works I'll turn it into a pack that includes a drawbar option.

I was going to try for another pocket before printing, but it's been slow work on the Athearn 89' cars as they need to be lowered quite a bit first. 

Jason

[C855B]

Ah, yes... the Roco ore car. Almost, but not quite.

Glad you could stay focused on this, Jason, as I'm in a million directions with the layout construction. Anyway, glue will likely be sufficient; my test using CA with the stock pocket alone (!!!) is holding very nicely for some reason.

[C855B]

After sleeping on this... I finally processed the thickness you're showing above the coupler pocket. Are you intending to fill the entire cutaway, like we discussed initially? Oops. We assumed incorrectly, by doing it that way the finished height will be way too low. That "slab" needs to be about 0.023" or so to vertically center the coupler. FWIW, I was designing the same backstop into my attempt, so we think alike there.

Anyway, take a look at the photo five posts up, and you'll see where it lands vs. the height gauge, using the stock pocket with no filler.

[wcfn100]

Anyway, take a look at the photo five posts up, and you'll see where it lands vs. the height gauge, using the stock pocket with no filler.

Looking at these 50X times their actual size causes all sorts of issues.  That piece you're looking at is .045" thick.  The MTL coupler box is .032" thick.  I've set my coupler box into the shim so it's flush in the inside top of the box which is a .012" thickness.  So my coupler sits .033" or .001" different than what you have.


It's all good. 


Jason

[wcfn100]

So on my way home from the Santa Express train in Cañon City, it popped in my head that my previous post, while convincing sounding, is way off as I missed a critical measurement.  However, without getting into the nitty-gritty, the coupler for the ore car should be within 2" (lower) than mounting the MTL box without a shim which makes more sense to me because I'd expect the MTL box to be too high.  Regardless, this will all come out in the wash as they get tested.


Jason 

[wcfn100]

So I sent off the new counter sunk boxes along with a few of the Atlas Ore car adaptors.  Hopefully without the sales going on, we're back to quicker turnaround.

Mike, I'll make sure the adapters work the way I envisioned and if you PM me a mailing address, I'll send a few to you to check out.  Since these don't screw to the body, I've been trying to figure out a way to eliminate the screw to save money while still being something that can be opened and serviced but with the brittleness of the FXD, I haven't come up with anything I'm happy with yet.


Jason

[wcfn100]

With hopefully a finished design in hand soon, it was time to document the procedure I'm using with the MTL True Scale Coupler.

First the coupler I'm using is the long shank version as the short shank won't give the look and feel of the prototype.



First, trim the coupler pieces off the sprue.



Next, I trim the gathering arm (looked that up, don't know if that's the best term) below the parting line.  This is more aesthetic but does create less friction.





Next I trim down the injection pin(?) as it sits between the two parts and could cause issues.



Then trim the fingers.



Next is the biggest step, cutting a gap in the mounting ring opposite the gathering arm.  This piece has no real forces on it and trimming it relieves some of the spring tension when trying to couple.



After that put the two parts together on a 00-90 screw and weld them together with a soldering iron right nest to the gap you just cut. 



Then to finish it off, the coupler pocket and lid.





Hopefully next time you see this will be the flat head screw version and brown couplers.


Jason

[Lemosteam]

I see what you did there!  Nice!  Some filing on the side opposite the gap in the ring could be used to tune the opening forces on the gathering arm and allow for smaller coupling forces.  I like that the two halves pivot together.

[Ken Ford]

Interesting modification you've made, Jason - I think I'll end up following suit, I'm trying to push boundaries and use MTS couplers for a small switching layout. I'm using #7 switches to prevent abrupt angles, but I'm finding the lack of swing and coupling effort using the stock couplers to be a challenge. They're great out of the package for running, though.