MTL True-Scale Couplers - Recommended Height?

[C855B]

Guess what? MTL gauge is not accurate on Micro Engineering Code 55 track. The gauge dogs are riding on the spike heads.

Comparing gauges. First pic is on C55, second is on Unitrack:



Vertical centering is correct with the MTL gauge on compatible track. Oops. 

[learmoia]

 

Pizza Cutters.... Micro-Trains... Code 55... Now it makes sense..

 

~Ian

[nkalanaga]

Maletrain:  I suspect that many passenger cars had couplers designed for more side play, and curve compatibility is a function of not only the car lengths, but the relative overhang.  Passenger cars and long freight cars have different truck spacings, so different end overhangs.

The problem with the prototype is not only the difference in overhang, but that there is no "rotational freedom" in the couplers.  If you watch our models, the couplers can change angles relative to each other, so even if both are as far to the side as they can go, the cars can still take a sharper curve, IF the overhangs are the same.

Prototype couplers basically lock into a rigid drawbar.  Once they've reached their maximum side swing, that's it.  That's part of the reason our cars can take sharper curves, and allow greater mismatch in overhangs.

Mike:  That explains the problem on ME track, and I knew it wouldn't work on their code 40.  But the Peco "code 55" has no inside spikes, and is designed for pizza cutter flanges.  My gauge also reads high there. 

[peteski]

As an interesting side-note I found out that the MTL Scale Couplers mate fairly easily with those awful Kato knuckle couplers.  There is some sideways stress there but they do mate.  If the MTL coupler whisker springs can be made much less stiff, this combination of couplers might work.

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[Peter Amling]

Thanks for posting Pete. Based on the design photos I thought they would mate with Kato knuckle couplers.

On an unrelated note I have started experimenting with mine and think we might need to start a thread on "recommended shank". I got packages of both kinds and have noticed that with some cars they couple too close if both have the short shank installed.

So far I've noticed on Fox Valley boxcars they will be too close with the short shank so I am using the long shank. With the RD4 hoppers the short shank does well.

Also can anyone recommend where to get some flathead 00-90 screws similar to those that come installed on FVM and Trainworx body mount couplers? They are much easier to work with and have a lower profile and shorter length than the ones supplied with the true scale couplers.

Next I will be installing these on Atlas and Kato diesels and do some more shank length testing.

[peteski]

Also can anyone recommend where to get some flathead 00-90 screws similar to those that come installed on FVM and Trainworx body mount couplers? They are much easier to work with and have a lower profile and shorter length than the ones supplied with the true scale couplers.

Next I will be installing these on Atlas and Kato diesels and do some more shank length testing.

Flat head screws will need countersunk hole in the coupler box and I suspect that FVM and TWX use metric-thread screws. But any hobby shop (especially Walters dealers) should stock Hobbits packs of 00-90 screws. Those are handy but very pricey.  For larger quantities I use http://www.specialshapes.com/ or http://www.microfasteners.com/ .

[nkalanaga]

I got my last batch of screws from J I Morris:
http://jimorrisco.com/miniature-screws/

Much cheaper than the hobby screws, if you can use a few hundred at a time.  The minimum for 3/16 inch 00-90 flathead screws is 144 for $22.25, or by the thousand for $128.50/1000.  They have lengths from 1/8 to 1/2 inch, and 1/8 would be very handy for 1015 couplers, but I bought the 3/16,  Next time I'll probably order 1/8, as they're the same price.

If you're really a glutton for punishment, they also sell 000-120, but so far I don't need any of those.  They're $182.80/1000 for 3/16 inch or 1/8 inch.

[Maletrain]

Some of my local hardware stores stock 00-90 screws, so you might try looking or calling locally.

[Mark5]

So far I've noticed on Fox Valley boxcars they will be too close with the short shank so I am using the long shank. With the RD4 hoppers the short shank does well.

Aside from the B&O box and the MILW ribsides, I think pretty much all FVM boxes should have extended draft gear.

Mark

[Peter Amling]

Aside from the B&O box and the MILW ribsides, I think pretty much all FVM boxes should have extended draft gear.

Mark

Thanks Mark! Would you happen to know whether the RD4-s should also have extended draft gear?

And this may be a silly question, but there seems to be a substantial difference between the "modern" FVM boxcars with extended draft gear, and say the Athearn 57' Mechanical Reefers. Is that also called extended draft gear or is there a different name for something that protrudes so far from the end of the car?

[learmoia]

Thanks Mark! Would you happen to know whether the RD4-s should also have extended draft gear?

And this may be a silly question, but there seems to be a substantial difference between the "modern" FVM boxcars with extended draft gear, and say the Athearn 57' Mechanical Reefers. Is that also called extended draft gear or is there a different name for something that protrudes so far from the end of the car?

I would say the RD4s should have the short shank coupler (No extended draft gear)..

Prototypically there is not much difference between Extended Draft Gear on a 50' box and a 57' reefer except for equipment manufacturer or maybe amount of cushion or

In the model world.. what we may run into is mfgs offsetting the screw holes to compensate for the size of the MT coupler itself to bring the cars closer together.  But when you throw a scale coupler into the mix it brings the cars TOO close together and the extended coupler is needed. 

However those cars may also prototypicaly require draft gear which can be achieved in the 3' view using the extended coupler, or in the scale model world  using an actual draft gear box with a scale coupler.. which they were doing with the Z scale FT Coupler in the 'Notes on Body Mounting' thread.

~Ian

~Ian

[ednadolski]

Anyone have any luck installing these on an MT 4650 hopper?  The coupler box is ~20 scale inches thick and hits the axle on the truck wheelset.  I thought maybe to invert the box and install without the lid, but that will raise the coupler height by 5 scale inches.

TIA,
Ed

[peteski]

Anyone have any luck installing these on an MT 4650 hopper?  The coupler box is ~20 scale inches thick and hits the axle on the truck wheelset.  I thought maybe to invert the box and install without the lid, but that will raise the coupler height by 5 scale inches.

TIA,
Ed

 For a prototype-size and appearance couplers their boxes are very unprototypical, but I understand the reasoning. Time to design a new photoetched coupler box? 

[ednadolski]

Time to design a new photoetched coupler box?

Not to hijack this thread, but briefly to address the question: The new coupler does not fit into the box for the LEZ, since the shaft is about 50% thicker.  The 'whiskers' on the MT also require a wider box, which when body-mounted could limit the truck swing for sharper curves.  So there are some design considerations that would need to be worked out.

Ed

[peteski]

Not to hijack this thread, but briefly to address the question: The new coupler does not fit into the box for the LEZ, since the shaft is about 50% thicker.  The 'whiskers' on the MT also require a wider box, which when body-mounted could limit the truck swing for sharper curves.  So there are some design considerations that would need to be worked out.

Ed

Ed, here are the internal dimensions of the coupler box.  If you made it from 0.010" brass you could make it quite a bit narrower. I think the coupler will still function as-designed if the inside width of the box was slightly larger than 0.124".  Those "whiskers" seem to be only utilized for opening the coupler during coupling. They are way too stiff to allow the coupler to swing sideways when car travels over curves.  The top and bottom of the box are 0.030" thick, so uing a 0.010" brass coupler box would reduce the height by 0.040".

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