Best Of Notes on body-mount couplers (work-in-progress)

[GaryHinshaw]

Hi Coxy,  a bamboo toothpick works just fine.  As DKS noted in his excellent review, the FT coupler was designed to be automatic but it didn't quite work as planned, so that aspect was shelved for now.  But the knuckles do separate easily with mechanical (as opposed to magnetic) force.

[bbussey]

Gary,
Out of curiosity, how close are the dimensions of the K&S rectangular brass tubing to those of the FT coupler box?

[GaryHinshaw]

Bryan, unfortunately not quite close enough.  The i.d. of the tubing is about .165 x .070 while the i.d. of the FT box is about .135 x .040.  The width is just large enough that there is no tension on the centering spring:



Also, the couplers look a little bit 'lost' compared to the size of the tube, but not too bad:



I have not been able to find a closer tubing size on the web, but if someone knows of any, I'd love to hear about it.  However, if you're interested in retro-fitting a car with this tubing already installed (as I'm guessing you are) there is one possibility that might be of interest: K&S has a channel stock with an i.d. of .125 x .032 (1/8 x 1/32) that fits the shank nicely:



and telescopes into the tube:



Depending on coupler height requirements, you could either telescope it in the top half or bottom half, then secure it with the screw you're already using.  By the way, the shank hole in the coupler is perfectly sized for an 00-90 screw. It should be mounted about .010 behind the front face of the box, so you might also need to trim the length a little bit.

Cheers,
Gary

[Philip H]

Gary,
What's your source for the FT coupler?

[GaryHinshaw]

Good question.  I've been using Z Scale Monster:

http://www.zscalemonster.com/full_throttle/100/

just don't look at the price!  (Actually the price is not bad for trucks plus couplers, but I don't need Z trucks.)  So far I've only bought two 4-packs to satisfy my curiosity.  Not sure what will happen in the longer run, but hopefully other options will present themselves.

-gfh

[DKS]

Just an FYI, reselling the coupler-less FT trucks (or the FT wheelsets, if the truck is destroyed) is not that hard. A number of modelers, including myself, are interested in these parts.

[bbussey]

Bryan, unfortunately not quite close enough.  The i.d. of the tubing is about .165 x .070 while the i.d. of the FT box is about .135 x .040.  ...

I have not been able to find a closer tubing size on the web, but if someone knows of any, I'd love to hear about it.  However, if you're interested in retro-fitting a car with this tubing already installed (as I'm guessing you are) there is one possibility that might be of interest: K&S has a channel stock with an i.d. of .125 x .032 (1/8 x 1/32) that fits the shank nicely ...

Actually, I was curious for developmental purposes how close they were.  Out of necessity, I'm going to be working with MTL knuckles for at least the next two ESM projects.  The FT coupler boxes look good on the tank cars and appear to mate well with MTL couplers, but one of my concerns is the lack of reliable magnetic uncoupling.  The inside dimensions of the brass tubing being .030" higher and wider than the FT box notwithstanding, it appears the outer dimensions are nearly identical based on your pics here, so working with a coupler box based on the K&S specifications is a possible interim step.

[GaryHinshaw]

Ah.  The o.d. of the FT box is 1/64 smaller in each direction: 11/64 x 5/64 vs. 12/64 x 6/64 (3/16 x 3/32) for the tubing.  The depth is about 13/64.

-gfh

[ednadolski]

Just a thought, how hard (and costly)  would it be to make a box from etched brass?   (Maybe Craig could lend some wisdom here?)

Ed

[bbussey]

That will be known within the next couple of months.

[ednadolski]

That will be known within the next couple of months.

 

[tom mann]

I like this thread.  Can anyone recommend a way to mount z scale couplers using the channel onto MT 50 foot boxcars?  IE, what size channel and screws do I need?

[GaryHinshaw]

Tom, a few questions: are you talking about an N or Z boxcar?  Do you want extended draft gear or not?  Are you thinking of the MT, FT, or AZL couplers?

As I noted above, I haven't found a very good option for fitting FT couplers into brass stock (the available sizes don't work very well - but the channel-in-tube scheme could work).  For N scale box cars with extended draft gear I have been going with the AZL couplers, as in this post.  The couplers don't look quite as good as FT, but they're decent, and the installation is pretty simple.

-gfh

[tom mann]

I'm thinking about N scale boxcars that have the extended draft gear.  I would use MT Z scale couplers (mainly because I have a stash of them).

[GaryHinshaw]

This entry is less about body-mounting than it is about ride height and detail corrections, but ride height and body-mounting go hand in hand, so bear with me.

Even though I'm in transit, I'm still devoted to Tehachapi, which means lots of centerbeams.  Red Caboose is the only game in town for 73' cars, but some of the details on their more modern single-panel and open-panel cars are amiss: e.g., the wheelbase is too short and the end bulkheads aren't quite right.  (The opera window & standard panel models are fine.)

Changing the wheelbase is straightforward: remove the underframe weight and cut the bolsters off just inside the truck pad and glue them to the floor in line with the last post in the centerbeam (and the little tow loops).  While you're at it, switch the trucks to BLMA 100T trucks for a much better ride height and appearance.  This will require grinding some material to clear the wheels, but this is simple.  (No need to file the bolster pad though.)  Here's how mine looked at this point:



This puts the model at just the right height for body-mounting the Full Throttle couplers directly to the floor of the car, as shown above.  I used the same styrene rod approach that I used on the corn syrup tanker.  I also added the now-standard air hose, cut lever & crosswalk to the package:



The last detail change was to partially correct the end bulkhead.  The end ribs on the prototype are all horizontal, but that would have been a pain to correct neatly, so I skipped that.  But a more visible change is to slice the top flange off the outer bulkhead section, and the triangular flange off the end of the top rib.  These can be seen as light green bits in the above photo (I haven't touched up the paint yet).  Finally, I added a grab-iron to the top of the bulkhead since it's such a visible detail.

The net effect is to give the car a much lower profile, both in ride height and overall height of the end bulkhead:





Now I'm going to need a few more so I can model this train, which is headed for Tehachapi:

http://railpictures.net/viewphoto.php?id=203309&nseq=0


-gfh