# Mason Bogie Coupler Conversion



## docwatsonva (Jan 2, 2008)

Mason Bogie Coupler Conversion

I finally received my new Accucraft Mason Bogie (Tenmile). As everyone has said, it is one beautiful engine; however, it comes with a link and pin (L&P) coupler and none of my rolling stock uses them. So the first thing I thought I would do is figure some way to add a knuckle coupler without modifying any part of the engine.

I measured the inside dimensions of the L&P box on the back of the engine. The height was ~ 0.190 inches and the width was ~ 0.279 inches.

The other thing to note is that, in order to come close to either the AMS or Kadee standard (?) coupler heights, you must use the lower L&P pocket.

Below are 2 ideas for modifying existing knuckles. I use factory Accucraft (AMS) couplers on all of my 1:20 Accucraft rolling stock. My other 1:20 stock, Bachman, scratch-built, and kits use Kadee “G” couplers. So I ended up modifying an AMS and a Kadee, short-shank knuckle. The Kadee knuckle was from a 789 coupler.


Accucraft(AMS) Knuckle Coupler:

The first photo shows the top view of an Accucraft stock and modified knuckle side-by-side. The AMS coupler shank is ~ 0.190 in high by ~ 0.280 in wide. I removed the spring pins and filed the shank width to the required 0.279 in. I also filed a little off the back. The lengths of both the AMS and Kadee knuckles are only a few thousands too long. So only a small amount needs to be removed from the length. I also filed small notches in the sides to allow some side-to-side swing.










The next photo shows a side view of the original and modified couplers. To get the proper coupler height from the lower L&P pocket, you must file the underside part of the shank.










Below is a picture of the installed AMS knuckle coupled to an AMS flat car. Pretty darn close I’d say.











Kadee Knuckle Coupler:

The next photo shows the bottom view of a stock Kadee and a modified one. The Kadee coupler shank is ~ 0.195 in high by ~ 0.275 in wide. I removed the spring pins and filed the sides flat to the required fit. I also filed notches in the sides to allow some side-to-side swing and filed a little of the back to adjust the shank length.










The Kadee coupler requires a bit more thinning to get the coupler lower in the L&P pocket. I took a Zona saw, clamped the knuckle in a vise with the shank up, and cut the shank approximately down the middle and removed the bottom half. This left me with a thickness of about 0.100 in. I then glued (thick CA) a 0.060 in x 0.250 in piece of styrene to the top of the shank. I drilled a hole in the styrene for the pin and filed it to fit the already trimmed shank.










The next 2 photos show the completed modifications.




















The last photo shows the installed Kadee connected to a Kadee coupler height gauge. As you may notice, the installed Kadee is approx. 1/16 in too high. I guess I could have filed the shank a little thinner but I was afraid it might have weakened the coupler. It’s not all that bad.










Both modified couplers are simply help in place with the provided pin.

I hope this helps those of you who wish to convert your MB to a knuckle coupler. It’ll be interesting to see if anyone can come up with another method.

Doc


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## chuck n (Jan 2, 2008)

Don:


The Climax comes with a L&P and when I got mine, Kadee had a coupler kit that fit into the L&P bracket. Your L&P bracket looks like the one on the Climax, only it has two levels for the link whereas the Climax has three or four positions. Mine is packed away, so I can't get to it to check.

Chuck


PS: Nice job Don. For the rest of you who might want to do the conversion the Kadee number for "G" is 782 and gauge "1' is 1782.


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## Kovacjr (Jan 2, 2008)

If Im not mistaken Kadee offers a coupler kit for the Bachman Climax that is a pin in to the link and pin pockets and needs to modifications. Should be a direct install with no changes as it was a custom coupler.


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## Mike O (Jan 2, 2008)

Doc and others, 

Thanks for posting. Saves me a bunch of homework. 

Mike


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## chuck n (Jan 2, 2008)

Here are some pictures of the Bachmann Climax conversion. The package contains two couplers, one for the from and one for the back. This may not work on the Front of the Mason Bogie.

The coupler is held in place with a pin that goes down through the box on the engine and there is a piece of bronze, or copper sheet that is bent to act as a spring to keep the coupler centered.






























Chuck N


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## docwatsonva (Jan 2, 2008)

It would be interesting to know what the thickness of the Climax Kadee shank is.

Chuck, what's the chance you could measure it? Of course my goal was to avoid any mods to the MB. The way I did it allows some swing of the coupler but not a return to center, necessarily. Right now I'm not sure what the minimum radius requirement is. I'll try to check it tomorrow. Too much football today.

Doc


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## chuck n (Jan 2, 2008)

I'll give it a try. It looks like it is the same thickness as the shank in the 789 only that it drops down rather that step up. It is the same one that is on the front of the Uintah and Sumpter Valley Mallets.

Chuck 


Just checked. It si 5.15mm (0.2003")

Chuck


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## Don Howard (Jan 2, 2008)

Thanks for the detailed posts. 
Now I won't have to figure it out myself!


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## placitassteam (Jan 2, 2008)

WOW!! Doc, you have recieved a Mason Bogie? I hadn't heard that they had arrived. Guess I will have to poke Greg Posta to ask "Where is mine?" Nice wright-up on installing a knuckle coupler. Thanks, Winn


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## Dr Rivet (Jan 5, 2008)

Winn 

Doc got an electric version. The live steam versions are due in CA during February....distribution after that


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## docwatsonva (Jan 2, 2008)

Thanks for checking Chuck. It appears that the Climax coupler shank will also have to be filed down a little bit to fit into the MB coupler pocket.

I dug out some Aristo 9' diameter track and checked out the coupler swing. It appears, form the picture below, that the coupler will work down to at least that diameter.










Sorry you have to wait a little longer Winn. It will be worth it.

Doc


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## Gary Woolard (Jan 2, 2008)

Doc, as we discussedin another thread ([url]http://www.mylargescale.com/Commun...ault.aspx)[/url] I just bought a couple new sets of Accucraft couplers with the intent to modify one for my Bogie. Part No. AP11738. But when I unscrewed the draft box to remove the coupler, this is what I found --









As you can see, rather than a short haft with a hole at the end, I have a rather longer one with a sort of 'box slot'. A spring fits inside the slot and the draft box, giving the coupler quite a bit of flexibility, but it sure doesn't help my application. Has Accucraft changed their coupler design, or did I somehow get a different coupler? 
Help please! I was hoping to drag my new combine at the Summer Steamup!


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## Dr Rivet (Jan 5, 2008)

Gary 

The couplers Doc was modifying are 1:20.3 NG Accucraft and Kadee 835; the one you show is [most probably] a 1:32 which matches the Kadee 820 / 920 shank. The 1:20.3 Accucraft coupler matches [in mounting style] the Kadee 835/836/837.


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## docwatsonva (Jan 2, 2008)

Gary,

Like Jim said.

Doc


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## Dr Rivet (Jan 5, 2008)

Gary 

I poked around in my Accucraft parts bins and confirmed: 
AP11-730 Couplers (pair) 1:20.3 
AP11-738 Couplers (pair) 1:32 

Based on the part number you posted, you have the 1:32 couplers.


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