# Type-F rotary couplers



## Burl (Jan 2, 2008)

I spent probably 2-3 weeks drawing this in Sketchup. Finally got to where I was satisfied I understood how everything was supposed to work & ordered my prints from Shapeways. They came in this morning. There are painted gloss black to make them easier to mold.

This is a departure from my past approaches. Before, I tried to figure out how to make the shank rotate separately from the head. This time, I am attempting to model a prototypical draft gear & yoke.


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## Burl (Jan 2, 2008)

First waxes:


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## Scott (Jan 29, 2008)

Mate very impressive work, raising the bar as always.


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## ewarhol (Mar 3, 2014)

Wow! Excited to see these in action.

Are your couplers compatible with any other manufacturers?


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## Burl (Jan 2, 2008)

Should work with Kadees. I can't guarantee that they'll work with everything, as I don't keep everything else on hand.


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## ewarhol (Mar 3, 2014)

Just worried about Kadee's. Have lots of #1 Kadee's all ready installed.


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## San Juan (Jan 3, 2008)

Very impressive.

If ever looking for future coupler projects, a type H (mostly used for passenger cars) coupler would be cool.


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## Burl (Jan 2, 2008)

Do you know of any drawings of type-H couplers you could show me?


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## Burl (Jan 2, 2008)

Finally got all the waxes made up for this one & mailed them to the foundry yesterday:











I would have been finished a week ago, but this particular piece turned out to be more difficult than I had imagined:












I re-made the mold at least 5 times. I kept getting air bubbles in the spring pocket. My first attempts were to cast it without the openings. I planned to carved them out later. However, the RTV is so thick, I never could get it to flow completely into the cavity. Even after I opened up the pattern, I still had trouble getting it to go in. In my last attempt, I vacuumed the RTV (a second time) after I poured the mold. Still, I had a couple small air bubbles, but I could cut those out of the casting. I am currently pouring yet another mold, which has been vacuumed, and is now curing in my pressure pot at 60 PSI.


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## Burl (Jan 2, 2008)

Made some progress on assembly today. Definitely the most complicated thing I have built in a while. Took me 3 hours to put one together. Hopefully the next one will go together faster. I think I counted 14 individual pieces, not counting springs.










It was able to successfully rotate 360 degrees:










I'm still experimenting to find the proper strength for the draft gear springs. It still seems a little stiff. I may try phosphor-bronze wire, instead of music wire.










The trip pin is actuated by a lever on the bottom (this is what the cut bar will press on the finished model). It has an internal spring to keep the pin down when the coupler is upside down. I used an HO scale Kadee knuckle spring for this. In this photo, you can see open vs. closed:


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## Scott (Jan 29, 2008)

Fantastic mate, looks great.


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## ewarhol (Mar 3, 2014)

Wow those look great Burl. Video coming soon of the rotary couplers in action?


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## Burl (Jan 2, 2008)

I hooked them up to a rotisserie and shot some video. First time I think I've tried something like this, so it may be a little rough.


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## Burl (Jan 2, 2008)




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## ewarhol (Mar 3, 2014)

Video is great on my end. Now I'm itching to get them on my coal cars.


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## Burl (Jan 2, 2008)

I had some time to work on the yoke drawing for the non-rotary end. This will eliminate a couple steps of assembly.


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## Scott (Jan 29, 2008)

Simply superb Burl, raising the bar again and giving it a spin too might I add.


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