Author Topic: Ideas for an Etched Pocket for the MTL True Scale Coupler  (Read 864 times)

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Ideas for an Etched Pocket for the MTL True Scale Coupler
« on: October 23, 2016, 12:48:30 AM »
The MTL True Scale coupler is a great new product for N scale.  Because it is a scale-sized coupler, the large plastic box that it comes with looks significantly over scale by contrast. So I wanted to see if it could be used with the etched metal coupler pocket from this thread a few years back.

While wider than a scale-sized pocket, the etched box turns out to be wide enough to fit the TSC. The TSC shank, however, is thicker than the box opening, and the hole location is too deep for the short shank TSC and leaves the long shank TSC sticking out.  None of these seem like insurmountable issues, so I came up with another drawing of the pocket that resolves these:

I am still concerned that the pocket might be too narrow for the TSC to actually function.  This is because the two plastic torsion springs molded onto the back of the coupler create a rather tight clearance around the pivot fulcrum.  However I would not want to make the pocket any wider as that would further limit truck swing.  The only other option I see to create additional clearance is to clip off the torsion springs and provide some other way to keep the coupler halves aligned while allowing them to pivot.  One way to implement that is a photo-etched spring, which is the all-red part on the left side of the drawing.   This works by folding up each side of the part perpendicular to the base, and then bending the leafs at a 45-degree angle.  Each leaf presses against either side of the shank and holds them together.  The spring would have to be made from phosphor bronze rather than brass, but it is simple enough to etch the entire pocket from that.  One obvious limitation is that it will not work with the short-shank TSC.  It will also probably take some tweaking with the dimensions to get a spring effect with the right amount of force.

Another possibility is that the leaf spring idea might be useful for adapting the TSC for cars that have integral pockets.




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Re: Ideas for an Etched Pocket for the MTL True Scale Coupler
« Reply #1 on: October 23, 2016, 02:02:25 PM »
I've been waiting to see what kind of magic you come up with.

Couple of thoughts..

I like the lief spring idea for installing couplers in existing boxes!! good idea.

Looking at the long shank coupler..
If you take out the wiskers then you can narrow the pocket significantly..
(Or design your box to taper down with the coupler profile. to give the illusion of a 'square' box at the end.

I would only worry about the ability for the coupler to close and not so much the couplers ability to self center.  (Real couplers don't self center)
.. I was thinking of just making a wedge or block that sets in between the wiskers and 'floats' in the box allowing the coupler more freedom to swing in in the box, and let the opening of the box determine the swing.. (wide for long cars, square for normal/short cars.

We need to petition Joe for a coupler only option!!..
.. but the more I think about it.. MT kind of reinvented the wheel when they didn't really need to.

Imagine a 1023 coupler shank but you closed the pivot point on each half  to eliminate the Slinky  but still used the spring behind that to close the coupler.
You can use existing boxes and it's a direct swap and you could do narrow-er scale boxes to reduce the pivot/off centerness..

Another note Ed, for retrofitting the existing boxes
The pivot hole of the long shank coupler DOESN'T line up exactly with the Old mounting screw so it's not a direct swap.. Your best bet is, You'd have to drill and install a new pivot pin for the short shank.

See if you can come up with a replacement bottom plate that folds up into the existing box and acts as a spring box for the existing wiskers.. and also gives the guide hole for the new pivot pin.


« Last Edit: October 23, 2016, 03:13:38 PM by learmoia »