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how to replace horn hook coupler with knuckle coupler

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how to replace horn hook coupler with knuckle coupler
Posted by Audioquest on Tuesday, September 17, 2019 1:32 PM

I have some HO Train trucks plastic that snap into the rolling stock that have horn hook couplers. I would like to replace with knuckle couplers.  Would someone know which type will work?

Thanks in Advance.  I would attach a picture of the trucks but unsure how.

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Posted by BigDaddy on Tuesday, September 17, 2019 3:38 PM

You want Kadee couplers.  They have a guide on coupler conversion.  https://www.kadee.com/documents/holist.pdf

I found the #148's less troublesome long term than the #5's. Specifically after 20 years the spring loses it's spring.   The #158's have a smaller knuckle to be more prototypical. 

Coupler height is important.  Kadee sells a height guage.  Athearn cars are usually close enough, just take the little clip off and pop the KD in.  If the coupler is part of the truck, I cut it off and mount the KD coupler box to the body using a 2-56 screw. 

Passenger cars with truck mounted couplers might require different

There are instructions on how to post photos at the top of the General Forum, basically you need a place that hosts photos, like Imgur.com Imgbb.com but not facebook or google

Henry

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Shenandoah Valley

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Posted by jjdamnit on Tuesday, September 17, 2019 6:03 PM

Hello All,

As Albert Einstein said, "Once you open a can of worms the only way to all the worms back in the can is to use a bigger can."

Welcome to the "bigger can" reply...

Audioquest
I have some HO Train trucks plastic that snap into the rolling stock that have horn hook couplers.

You didn't mention if the couplers are truck mounted; TALGO, or body mounted.

Kadee does make a TALGO truck replacement kit. I have used these before and found these not as reliable as body mounting.

To body mount the couplers you will need to invest in several tools that you might not have in your current tool kit:

  • 2/56 tap & tap handle
  • #50 drill bit
  • Pin vice
  • 2/56 screws (I recommend Kadee #256)
  • Kadee couplers and draft gear boxes
  • Kadee fiber washers- -#208, #209 & #210
  • Kadee #206 Coupler Height Gage
  • Centering ruler (not necessary but a great tool to have)

You can reuse the original trucks and mounting hardware.

To body mount the couplers you will need to remove the TALGO coupler box by cutting it off the trucks.

This is best done with a utility knife after removing the trucks from the car.

Then find the center line of the car (this is where the centering ruler saves time and headache).

The Kadee draft gear boxes have a center hole. Line the center hole up with the center line and mark with a punch or scribe.

Drill a pilot hole with a #50 drill bit.

With the 2/56 tap thread the hole.

Assemble the coupler and the draft gear box.

With the 2/56 screw attach the coupler assembly.

Replace the modified trucks using the original hardware.

Place on a section of track and measure coupler height with the #206 Height Gage.

This is where it gets tricky...

If the coupler height is too low you can use the fiber washers to raise the car body.

CAUTION: if you have to use more than one of each washer in a single stack to align the coupler height you should consider using an overset coupler. 

If the coupler height is too high you could use smaller diameter wheels; 28- vs. 33-, 33- vs. 36-inch.

Or, you could could use underset couplers.

Coupler conversions can be more involved than many suspect.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by Audioquest on Tuesday, September 17, 2019 6:34 PM
couplers are truck mounted no screws
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Posted by MisterBeasley on Tuesday, September 17, 2019 6:54 PM

Is there any reason this car is special?

I've had a couple of these.  I cut off the coupler brackets from the trucks and mounted Kadee draft gear boxes on the car.  Then, I mounted Kadee couplers in the boxes.

I probably replaced the wheelsets with metal wheelsets, too.  They roll much better that way.

After that, it cost more for the couplers and wheelsets than the price of the car in a box under the table at a train show.  Now, I pass such cars by.  Too much trouble.

It takes an iron man to play with a toy iron horse. 

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Posted by riogrande5761 on Tuesday, September 17, 2019 7:54 PM

Audioquest

I have some HO Train trucks plastic that snap into the rolling stock that have horn hook couplers. I would like to replace with knuckle couplers.  Would someone know which type will work?

As others suggest, cut the coupler boxes off the talgo style trucks.  Then buy Kadee #5 couplers which come with their own box.  Also buy a Kadee height guage.  You'll need to probably shim the spot where you will mount the draft gear box such to match the coupler height to the guage.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by hgodling on Tuesday, September 17, 2019 10:16 PM

I am also looking into replacing the couplers on my cars.  What is the issue with passenger car couplers on the truck? I did noticed that the box has a long extender from the truck. 

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Posted by SeeYou190 on Wednesday, September 18, 2019 6:05 AM

JJ gave a fantastic response.

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I would also suggest looking around the Kadee website.

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My personal preference is for "standard size" head couplers. If they fit, my favorite is the #148 whisker coupler in #242 universal coupler boxes.

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Kadee offers almost limitless alternatives and options.

.

-Kevin

.

Living the dream.

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Posted by MisterBeasley on Wednesday, September 18, 2019 9:42 AM

hgodling

I am also looking into replacing the couplers on my cars.  What is the issue with passenger car couplers on the truck? I did noticed that the box has a long extender from the truck. 

Passenger cars are generally long, and the couplers need a wide angular swing to make it around tight curves.  This can be done more easily with Talgo mounts.  Sometimes a swing-mounted coupler will work.

I have some not-too-long Rivarossi passenger cars which are fitted with body-mounted swing couplers.  They make it around 18 inch HO curves, but they can be finicky.

It takes an iron man to play with a toy iron horse. 

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Posted by dstarr on Wednesday, September 18, 2019 9:49 AM

Just a few comments.  If mounting couplers/coupler boxes to a plastic car, you don't need to tap threads for the screw.  The 2-56 screws have no trouble cutting their own threads in plastic.  I don't like to secure coupler box lids with glue.  I might need to get the lid off in the future should the coupler spring stop centering the coupler, or the coupler breaks. 

I like body mounted couplers, at least on 40-50 foot freight cars.  In addition to looking better, body mount couplers permit you to back up a train and stay on the track.  The Talgo couplers push on the trucks and just a little misalingment and the thrust twists the truck and deralis it.  For longer cars (passenger cars) talgo truck mount couplers help getting around 18 inch radius curves. 

   A #5 Kadee wil fit most cars.  No so for locomotives.  Kadee has a what-fits-what list that covers every piece of rolling stock manufactured over the last 50 years.  You can save yourself a lot of filing, cussing, and hacking by using the Kadee recommended couplers on locomotive conversions. 

Coupler height needs to be standardized.  If you have one coupler high and another coupler low, the couplers have less metal to metal contact and are likely to uncouple when they encounter any little fault in your trackwork.  You can check coupler height by merely eyeballing a train as it goes by.  If all the couplers are at the same height, all is well.  If you see couplers riding high or low, it is time to do some standardization.  You can use the Kadee height gauge.  I made my own height gauge from a little block of wood, cut to just the right height and an old coupler screwed onto the top.  I used the NMRA gauge to get the height just right.   As a rule, the Athearn blue box cars have low coupler boxes.  I use ordinary #6 flat washers, which I get down at Franconia Hardware, under the trucks to raise the whole car up.  I have never encountered a car with high couplers, it's always low couplers which the washers fix right up.   

 

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Posted by kasskaboose on Wednesday, September 18, 2019 10:01 AM

Youtube has some great vids to check out before you start.  This can be a difficult issue if not done correctly.  I did it on a few cars and swore not again.  Unless you have a lot of cars to replace, the cost of the parts is more than just buying knuckle coupler cars. 

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Posted by IRONROOSTER on Wednesday, September 18, 2019 11:36 AM

hgodling

I am also looking into replacing the couplers on my cars.  What is the issue with passenger car couplers on the truck? I did noticed that the box has a long extender from the truck. 

 

The major issue is backing up.  The couplers tend to push sideways which can push the trucks off the track.  This is worse on curves or through the diverging leg on turnouts.  This problem can be eased by not using sharp curves or low numbered turnouts.  Weight can also help but reduces the number of cars your locomotive can pull.

All of that said, truck mounted couplers do allow the use of sharper curves.  If you want to run full size passenger cars on a small layout, truck mounted couplers are the way to do it.  You can also use them on freight cars if you need extra sharp curves.

Paul

If you're having fun, you're doing it the right way.
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Posted by MisterBeasley on Wednesday, September 18, 2019 12:01 PM

I disagree that setting all your couplers to the same height is sufficient.  Instead, set them all to the universally accepted height as defined by an approved coupler gauge.

For one thing, you won't have to reset every new piece of rolling stock to "your standard," but hard-to-adjust things like new locomotives can be run immediately without having to fix what wasn't broken in the first place.

It takes an iron man to play with a toy iron horse. 

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Posted by Eilif on Wednesday, September 18, 2019 7:45 PM

If you don't want to fuss right now with body mounting all your couplers, you can use the existing truck mounted coupler position.  

You simlply need a pack of the Kadee #212 Talgo Truck adaptors (they come in a pack of 24 for a couple bucks).  You put a KD in the spot where the horn hook was (I recommend KD#148) and snap a Talgo adaptor over the hole.  If the height is a bit to high or low, you can buy #148-style (though they have different numbers) that raise or lower the coupler height a bit, but generally the truck mounted couplers end up very near the standard height. 

I've had very good luck with these.  If you're running long trains of 15 cars or more, then maybe you should invest in body mounted couplers.  

Of course if you truck mount them now and decide to go body mounted later that's just fine. You can easily re-use the couplers and you'll only be out the 25 cents you paid for the adapters. 

The second issue you raised was for the long couplers on many older passenger locos.  You can body mount if you want, but there are also long arm knuckle couplers available.  They are unfortunatley plastic, but they work fine. As others have mentioned, truck mounted couplers typically -though not always- work better on tight curves than body mounted couplers.

Another option for passenger stock is semi-permenantly connected dummy couplers.  

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Posted by rogerhensley on Thursday, September 19, 2019 6:05 AM

Here is a drawing included description of a process.

http://madisonrails.railfan.net/eci/retrucking.html

Roger Hensley
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Posted by SeeYou190 on Thursday, September 19, 2019 3:14 PM

IRONROOSTER
If you want to run full size passenger cars on a small layout, truck mounted couplers are the way to do it. 

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Yes. I tried body mounting some couplers on passenger equipment, but they worked better as mounted to the trucks.

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Now I even still use the horn-hook couplers, I just cut off the bottom 2/3 of the trip pin.

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Very rarely do I have a problem. I do not go backwards.

.

-Kevin

.

Living the dream.

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Posted by jjdamnit on Thursday, September 19, 2019 9:46 PM

Hello All,

dstarr
...you don't need to tap threads for the screw. The 2-56 screws have no trouble cutting their own threads in plastic.

Not necessarily. The screws I referenced in my parts list are nylon, not metal.

These won't "self-tap" into plastic.

I suggested the nylon because they can be cut to length, if necessary, with standard side cutters.

Rather than investing in several different lengths of metal screws the nylon ones can fit many different needs.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by BN7150 on Friday, September 20, 2019 12:55 PM

The attached photo shows the danger of the truck-mount in O scale, which is the same as in HO scale. Can you see that there is no problem with pulling and that it is easy to buckle with pushing? With the truck-mount, a short train is safe, but a long train is dangerous.

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