Brass Loco pilot: Adding a "functional" coupler

[Mike Madonna]

Good evening all,

I am in the midst of a semi-involved "re-hab" of a Key SP AC-5 "Cab Ahead" loco.
This loco will be a "runner", not a shelf/Glamour Queen, LOL.
That said, I'd like to add a functional coupler to the pilot. Currently, the entire pilot is NOT attached to the loco (another item to fix, more on that later). I included detailed photos of the SP "Stamped Steel" pilot from the loco. This pilot was also on some other Key SP Steam offerings. I would prefer to make this "mod" before I reattach the pilot to the chassis. A traditional coupler and box (ie. MTL 1023, 1015, 2004, etc.) may not be feasible due to the location of the screw that attaches the shell to the chassis. The photo of the pilot & chassis is just press fit together. Hole in chassis is for assembly screw (shell-to-chassis). Screw in chassis is for front 4 wheel pilot.
As for permanently and properly attaching the pilot to the chassis, I am open for suggestions. Soldering would be a way, but I question a soldering iron or gun in this case. Perhaps a Resistance Unit may be a better choice. The other thought was JB Weld 2 part Epoxy. The loco would likely be a "road" engine more than a "helper". Considering this is a Samhongsa built AC, it will require wider radius curves due to the front engine being ridged (read fixed) to the chassis. Appreciate any input, Thanks!
Note: Could not upload photos due to "uploader folder" is full 

[Cajonpassfan]

Mike, when you say front engine being fixed, you mean the one next to the firebox, right? Just like the prototype? So what kind of minimum radius will it require? And does the coupler need to be automatic/semiautomatic like an MT or clone, or will a "bamboo stick" uncoupler do the job for the occasional helper coupling/uncoupling?
Too bad we can't see pics (yet?)
Otto

[peteski]

Note: Could not upload photos due to "uploader folder" is full 

You probably tried to attach them to the post.   you should be able to upload them to your TRW gallery.
See the Admin/FAQ section for uploading instructions if you haven't done that in the past.

[nkalanaga]

If function is more important than scale appearance, I'd suggest one of Athearn's McHenrys.  They don't actually need a draft gear box at all, if manual centering is acceptable.  Just cut the shank to length, drill a hole through it and the pilot, and mount it with a piece of wire, so it can pivot a little.

[mmagliaro]

Without photos, I can't be of much use here, except to say...
As a general rule, if you are going to go with JB Weld or other epoxy, drill holes and insert wire pins through the joint
in addition to the epoxy.  It makes a big difference in strength and the ability of the joint to withstand flexing, which is likely on a coupler.   Use steel music wire for rigidity.  Allowing the joint to flex back and forth over time is what eventually makes it break.

[Mike Madonna]

Let's try this....



















Hope these photos shed some light on the situation. Obviously, I'll have to remove the scale "dummy" coupler. Then clearance a "slot" in the pilot for the coupler shank. Since my initial post I had an idea. The IM Cab Aheads come with extra couplers similar to a McHenry coupler (two piece, with a round loop to mount). This "loop" could possibly fit around the screw that attaches the front of the shell to the chassis. The last photo shows the hole I speak of. The screw shown is what attaches the lead truck to the chassis. As an aside, I DO own a Resistance Soldering Unit. I just do NOT currently have any experience with it.... yet   

[robert3985]

Mike, If you're going to be doing quite a bit of brass rehabilitation, and/or if you like working with brass and intend to build brass models or modify your brass engines & cars, then, as you have surmised, a quality resistance soldering station is essential. Also, a regulated soldering iron is also essential, but for many soldering requirements that need precision placement of brass parts that are fairly massive to be joined, without de-soldering other components of the model, then a resistance soldering station will change your soldering world.

My recommendation for brass engines/car repair in scales up to O is the American Beauty 250 Watt Station #10502 with the "light capacity" tweezer tool. Also get the "light capacity" 3/16" Carbon Probe Style Handpiece #10525, and the Return Lead w Alligator Clip #10512A.  Also get extra #10525 3/16" Carbon Electrodes, and extra #10542 5/16" Steel Electrodes.

If you're not going to do anything in a scale larger than HO, then the 100 Watt Station will work just fine and save you some money.  Go with the same tools as above however. 

You can buy American Beauty Resistance Soldering Stations at Micro Mark, and right now, they've got a sale going on...and you can save quite a bit.  Their American Beauty tools are the same price as buying directly from American Beauty, but their "sets" are nearly $100 off the list price.

Another item that aids greatly in precision resistance soldering is the Micro Mark Grounding Vice for resistance soldering. It's built for their cheap in-house resistance solderer, but can be used with the American Beauty Grounding Cable.

Micro Mark Resistance Soldering is here: https://www.micromark.com/search?keywords=resistance%20soldering

One last, but important thing.  Don't use plain old lead-bearing solder on your brass models.  One of the reasons that brass models break at the solder joints is because the makers are cutting corners by using tin/lead solder.  I switched over to solid core 96/4 Tin/Silver silver-bearing solder years ago because it's 5 to 6 time stronger than Tin/Lead solders, doesn't oxidize nearly as much and does a much nicer, cleaner joint.

Equally important is to use the best flux made for brass/nickel silver/bronze/copper which is Superior No.30 Supersafe Soldering Flux, which will literally turn you into an expert solderer.  This flux is self-neutralizing from the heat of soldering so your joints won't corrode and make soldering MUCH less of a hassle.  Buy it here: https://superiorflux.com/products/superior-no-30-soldering-flux/

As for couplers for the front of your engine.  If it were my brass engine, I would want something that not only was functional, but looked good too.  Extra-big N-scale couplers may work okay, but they are the main identifier that your model is N-scale.  I prefer a coupler that, even if it doesn't look exactly prototypical, is within a couple of percentage points of being the correct size...and it will work with most N-scale couplers (particularly MT couplers).  If you're using Magne-Matic uncoupling this coupler works with that, but if you're not, you can just snip the magnetic dongle off for a more realistic looking coupler.  I'm talking about the Micro-Trains 905/903 Z-scale couplers, which I have used for decades on both cars and engines.  You just have to make sure they're exactly the right height.

I'm converting over to Micro-Trains True-Scale couplers that I modify and put in 3D printed coupler boxes but they're not compatible with any other N-scale couplers and don't couple together as easily either.  BUT, they are the correct size for a prototypically correct N-scale coupler and appear much more prototypical.

Photo (1) - Micro-Trains #903 Z-scale coupler mounted to my super-detailed/modified Hallmark "Union Pacific Welded Steel Caboose" which needed my resistance solderer to desolder parts and install new ones:


Photo (2) - Micro-Trains #903 Z-scale coupler vs a scale-sized dummy coupler double-heading Key USRA UP Light MacAthurs:


Photo (3) - Micro-Trains #903 Z-scale coupler on my kit-bashed UP CA1 Caboose vs Micro-Trains N-scale coupler one of my Atlas GP9's:


Photo (4) - Micro-Trains #903 on the tender of one of my superdetailed Key Big Boys..which incidently, I detailed using my resistance soldering station:


Photo (5) - Just for giggles, here are Micro-Trains True-Scale couplers mounted on my UP CA1 Caboose and my BLI F3A:


Hope this helps a bit.

Cheerio!
Bob Gilmore

[ATSF_Ron]

Mike, you mention possibly using the screw that mounts the frame to the boiler for a coupler mounting screw.  I no longer have my AC-6, but I took many photos while working on it.  I think that idea may not work for two reasons.  1) The mounting point is a bit higher than the horizontal mounting height of the needed coupler, and 2) That same screw is, I believe, also too far back for any type of coupler box or coupler mounting mechanism to fit properly.  I also took a look at an Intermountain AC-12 I have and came to the same conclusion.  It has a similar, if not identical, tank under the cab which the Key model uses as a mounting point.

At any rate, good luck!  This will be interesting to follow...

[Mike Madonna]

Robert,

As always, nice work and very useful/insightful advice! Regarding my current Resistance Soldering "set up", it consists of the following:

- Hotip 100W Res. Soldering Station (w/ foot pedal), unit looks to be almost brand new.
- American Beauty Light Tweezer Style Handpiece, Model #10541 (New)
- H&N Electronics 96% Tin/4% Silver Solder Solid Wire .031 (1 ounce)
- H&N Electronics Superior No. 30 SuperSafe Soft Soldering Flux Gel (2 Fz)

The only issue right now is the Hotip uses studs and nuts to secure the cables to the unit. The 10541 uses "tapered pins" at the cable ends. According to a tech at AB, I can convert the pin ends to ring lugs to attach to the Hotip.

Ron,

I'm giving this thought as I go along. Robert made good points about looks, functionality and operation regarding a "working" front coupler. In my second post (with photos), I mentioned about couplers IM provided with the AC. There is a "short" shank coupler installed on the loco pilot from the factory. In the little bag (along with extra traction tires) is a "long" shank coupler. Like I said, exploring all options....

[Mike Madonna]

For those following, here is a pic of the pilot "press fit" onto the chassis. To the left is a MTL coupler height gauge. Above the chassis/pilot is the long shank IM front coupler (in the tweezers) that I spoke of in a previous post. I tried to line up the mounting hole in the back of the coupler with the hole where the chassis-to-shell screw is located. This may shed some light on what I was considering.

[robert3985]

Robert,

As always, nice work and very useful/insightful advice! Regarding my current Resistance Soldering "set up", it consists of the following:

- Hotip 100W Res. Soldering Station (w/ foot pedal), unit looks to be almost brand new.
- American Beauty Light Tweezer Style Handpiece, Model #10541 (New)
- H&N Electronics 96% Tin/4% Silver Solder Solid Wire .031 (1 ounce)
- H&N Electronics Superior No. 30 SuperSafe Soft Soldering Flux Gel (2 Fz)

The only issue right now is the Hotip uses studs and nuts to secure the cables to the unit. The 10541 uses "tapered pins" at the cable ends. According to a tech at AB, I can convert the pin ends to ring lugs to attach to the Hotip.

Ron,

I'm giving this thought as I go along. Robert made good points about looks, functionality and operation regarding a "working" front coupler. In my second post (with photos), I mentioned about couplers IM provided with the AC. There is a "short" shank coupler installed on the loco pilot from the factory. In the little bag (along with extra traction tires) is a "long" shank coupler. Like I said, exploring all options....

Very good!  I would suggest the "probe" tool with the grounding cable too which makes it easy to solder on surface details that you can't clamp with the tweezers.  It's how I solder on grab irons without drilling a mounting hole using the 96/4 Tin/Silver silver-bearing solder that's 5 times stronger than plain ol' electrical solder. You can see 'em on my CA8 caboose photo if you look at the grab ends, and on the long grabs on the rear of my Big Boy's tender.

Unfortunately, H&N Electronics, my go-to shop for solder and Superior #30 Supersafe Soldering Flux has closed shop and is out of business.  Thought everyone should know, so if anybody wants that "best" flux, you'll have to deal directly with Superior, and get your 96/4 Tin/Silver solder from someplace like Kester.

Cheerio!
Bob Gilmore

[ATSF_Ron]

Mike, that long shank coupler looks like it may do the job!  For me the tricky part would be opening up a space in the pilot for it.  Yikes!