Kadee position in relation to buffers help please

[ThePurplePrimer]

Hi guys

 

I am planning on building a few ( of various types ) 4mm wagons and intend to use 146 Kadees

 

I understand that I need to get them at the correct height and I have the gauge to do this but I am unsure how I should position them in relation to the buffers ( I will be using fixed buffers )

 

I think it would look best if the stick out as little as possible but then I am guessing I need to consider the issues of potential buffer locking ?

 

Could anyone tell me how I should be positioning them please

[brossard]

Rob, it depends on your smallest radius so you might want to do some trials.  My rule of thumb is to set the knuckle hinge in line with the buffer head.  Too far in and you won't get the coupler to make or the buffers will foul each other.   For height, I have found that mounting directly under the buffer beam is about right, but do use the gauge to confirm.  Watch for droopiness, a sliver of 0.010" strip usually cures that.  Blu Tak can be useful when trying to see how things fit.

 

John 

[ThePurplePrimer]

Hi John

 

Thanks for the reply

 

Could you explain where I should be putting the strip of 10 thou please

[brossard]

If the coupler is droopy, the 0.010" sliver will shim it up.  It should go between the bottom of the draft gear box and the metal coupler.  A dab of plastic solvent will stick it without affecting the coupler.  It's happened to me a couple of times but if, when you assemble the gear box you clamp it, there shouldn't be a problem.

 

John 

[ThePurplePrimer]

That makes sense - thanks

 

I also am wondering about not using a fixing screw

 

I was thinking of glueing the box to the underneath of the wagon ( shimmed as required ) and then just clipping the lid on. This looks to me like its a tight enough fit to be fine without a screw - or does experience suggest otherwise ?

[Dunsignalling]

That makes sense - thanks

 

I also am wondering about not using a fixing screw

 

I was thinking of glueing the box to the underneath of the wagon ( shimmed as required ) and then just clipping the lid on. This looks to me like its a tight enough fit to be fine without a screw - or does experience suggest otherwise ?

If you don't use a screw, the coupling will have a greater tendency to droop. Whilst the clip-fit lid seems quite secure, in my experience it comes off quite easily without one.

 

Anti-droop shimming can also be done using the larger size of Peco fibre washer and I think Kadee make something similar themselves.

 

As to alignment, my preference is to get the inside rear face of the knuckle in line with the buffers. This results in a gap of about 4mm between the buffers of adjacent wagons which is plenty for 2' radius curves but a bit tight if you want to propel through second radius set track crossovers though they will pull through quite happily. If in doubt fit temporarily using double sided tape etc and try them out.

 

Hope this helps. If you want more info there is a fairly massive, though not recently active, thread on here about using Kadees on British outline stock which will repay the time spent wading through it.

 

John

[brossard]

I'd recommend gluing the draft gearbox together using a strong solvent.  Hold it with some sprung self closing tweezers for a short while.  I used to use screws but lately I've been gluing the gearbox to plastic strip behind the buffer beam -- so much easier.

 

Here's what I think is a pretty good example:

 

 

You can see the height and relationship of the knuckle to the buffer head.  You can also see that the wagons are quite close coupled.  As I said though, this depends on your radii.  For me, I don't use magnetic uncoupling so I cut off the trip pins.  The couplings shown are scale head - #156 I think.

 

I could only find this picture of the underneath:

 

 

The wagon on the left has scale head and is EM.  I used a long shank which is why the gearbox is inset so much.  Medium shank are generally the best.  The wagon on the right is unconverted and uses NEM.

 

John

[Andy Reichert]

 

  The couplings shown are scale head - #156 I think.

 

SNIP

 

Apologies in advance if this seems picky, but RM is usually seen as a  good information source.

 

Note: "scale head" is a Kadee "marketing concept". I'm not sure how even that description might apply on a private era 4mm coal wagon.

 

The only scale HO knuckle couplers are made by a small outfit called "Sergent Engineering" in the USA.

 

Andy

[brossard]

I don't disagree Andy.  I was looking for something less clunky than the standard head - not specifically something to 4mm scale.  The NEM types are really quite horrid IMO.  I think the "scale heads" are a lot less obtrusive, especially without trip pins.

 

John

[ThePurplePrimer]

Thanks again for the replies

 

I was tempted to go for the NEM version to give me the option of any future coupler developments ( assuming of course that supports NEM )

 

I am just starting out but might be playing with what I make now in 20 years time so I want to try and make some sensible decisions now.

 

That said the non NEM version look better in those photos

[brossard]

Indeed Rob, I've been playing with Kadees for longer than that.  Still learning too.

 

John

[Dunsignalling]

Thanks again for the replies

 

I was tempted to go for the NEM version to give me the option of any future coupler developments ( assuming of course that supports NEM )

 

I am just starting out but might be playing with what I make now in 20 years time so I want to try and make some sensible decisions now.

 

That said the non NEM version look better in those photos

Hi. Rob,

 

I've also been using Kadees for about 20 years and the best advice I can give you is to play around with one loco and three or four items of stock for a while before getting going on your whole fleet.

 

You will quickly get a feel for what works well as opposed to nearly working well and establish whether you have set them at the length that best suits your layout. 

 

I sometimes run my stuff on layouts that can accommodate trains 50-odd wagons long and value the extra confidence screws give. I once had a #18 NEM coupler pull out of its pocket on the back of a heavily laden loco though it was hauling a test train of 30 coaches! That said, I have just fitted a pair of #17s to my new Bachmann 1F tank (which won't be exposed to that kind of abuse). I was delighted to find they seem to be getting the pockets right at last.

 

When using non-NEM Kadees (most of the time) I nowadays prefer to glue the box to the vehicle (ensuring that it is central and square) so that it cannot turn and use a screw as belt-and braces and to secure the lid. The biggest size of Slaters Microstrip is very convenient for making up mounting blocks to support couplers where necessary.  

 

John

[HeavyDuty]

I'm currently converting 36 HAAs and a dozen vee tanks to Kadees to run on our club layout at shows.

 

I've settled on a mounting height that is about 12mm above the rail head - I simply added a 0.090" shim under a Kadee height gauge and match everything to that. I'm using the scale head (sorry, Andy - it's common usage even if not quite accurate) Kadee 156 couplers in 252 boxes; right now I'm experimenting with their placement relative to the buffers so they will operate on the tightest radius found on our club layout. The pivot lined up with the buffer face seems to be about right, but I'm still fiddling.

[Guest 40-something]

I use Kadee's on my stock, I glue the draft box to the underframe and put a little glue on the cover - 1 rough shunt will pop the cover off if not glued.   I also replace the NEM boxes with draft boxes and No. 5's as I find the NEM's have a tendency to move to one side, which affects coupling and uncoupling,  Non-NEMs look a bit neater too.

 

I line the inside face of the knuckle up with the bufferheads, my tightest radii is on the Peco asymetric 3-way point.

 

Best advice, elaborating on the advice given above, play around with your longest loco and longest wagon/coach to get an idea of the spacing you need

[Il Grifone]

The recommendation for the Peco Simplex coupling (which is similar in operation to the Kadee) is to have the coupling surface 1/8" in front of the buffer faces*, extending this to 3/16" for sharp curves. The buffers should just not touch when pushed around the sharpest curve to avoid the possibility of locking (the general 'slop' in 00 tolerances makes this likely, if buffers are actually allowed to do their job).

 

The operating height (10mm) is based on US standards for H0 scale (though the Peco operates at the same height). British prototype buckeyes are set at buffer height with either no buffers (as in the US) or retracted buffers. Hornby Dublo fitted most of their stock with puny short buffers to avoid the overscale spacing otherwise necessary.

 

* This is a reasonable compromise, being only about a couple of mm more than the prototype dimension.

[Grovenor]

I never heard of a prototype dimension for a Peco Simplex coupler! What prototype are you comparing it with?

Keith

[John Tomlinson]

Cutting off the trip pins has already been mentioned and should be seriously considered before starting out. Apart from the cosmetic benefit, any droop in the coupling can easily result in the trip pin fouling on points with potential damage to both point and vehicle.

 

I've found putting the coupling in a vice and then cutting the pin off with a small hacksaw works quite well - try to hold onto the head as you do so to discourage movement and the spring flying off! Your pack of Kadees should contain a little see through phial with spare springs if needed, and its well worth keeping any leftovers for the future. Once the pin has gone you can clean up with a small file,  but you need now to concentrate a bit harder as to which way up the coupling goes as the pin is no longer there to indicate down!

 

John.

[brossard]

I agree with John T that whether one keeps the trip pin or not should be considered.  I generally go for smaller layouts with easy access for a bamboo skewer (used to twist the knuckle open for uncoupling).  I have heard it said that some layouts have areas that are not accessible for hand uncoupling.  So, do think about what you will need for uncoupling.

 

John

[ThePurplePrimer]

Thanks for the additional info

 

It's an interesting question for me to consider. I quite like the idea of manual uncoupling but my layout will be in my recently converted attic. Although I can easily stand up in the middle that won't be the case at the extremities of the layout.

 

I am intending to operate sitting in an office style chair and my layout will be up to 16 feet long.

 

With all that said I am yet to decide what from my layout will take and how much uncoupling will be involved.

[Grovenor]

Leave the trip pins on until you know what you want. Its a trivial task to cut them off later should you feel the need, its a lot harder to put them back on!

And while bamboo skewers may work OK for wagons they are pretty useless when the coupler is under a gangway on the end of a coach.

Keith

[brossard]

You are absolutely right Keith.  Goods stock and coaching stock may need to be treated differently.  Accessible or auto uncouplers are needed if wagons are to be shunted.  For coaches though, the majority of ops I have seen are where the train pulls up to the station (it might stop if you are lucky) and then proceeds again.  For operations like that, I make my rakes permanent using hook and bar couplers a la Tony Wright. I put a Kadee on at least one end and sometimes a dummy screw link on the other.  In the club I used to belong to, someone had the bright idea to change locos on a passenger train during an exhibition.  It was utter chaos  , blocking the line for ages, and completely contrary to what punters want to see - trains going 'round.

 

John

[Gene]

Quite frankly I don't find the trip-pin on the Kadees to be so visually ugly that I feel the absolute need to remove them.

Plus the real issue with cutting the pins off the Kadees is it is an action that can't be undone, once the pin is cut-off it can't be put back on, making the coupling useless for hands-off magnetic uncoupling should that be ones choice sometime in the future.

At least by leaving the pins on one has the choice to use magnets and/or skewers for uncoupling now or later on. So unless you find the pins so unattractive that you can't live with them then I suggest leaving them on for the time being. You can always remove them later on down the road.

 

Cheers

Gene

[BR60103]

I can never get the pointed sticks to work from the top. If I have to use them, I use it to pull the nearest trip pin over.

I find, though, that I can usually bring a train into Windermere and stop with just a little bump and then drive the loco away from the coaches.

[Il Grifone]

I never heard of a prototype dimension for a Peco Simplex coupler! What prototype are you comparing it with?

Keith

 

There is of course no prototype for the Peco Simplex. I was referring to the distance between headstocks of two prototype vehicles, coupled by a standard 3 link coupling (around 3' 6" or so IIRC*). Using the 1/8" dimension this becomes roughly a scale 4' 6" using normal wagon buffers (a bit more than the couple of mm I quoted, but getting closer involves large radii and spring (or retracted/short) buffers and couplings.

 

* I don't have reference to my library to check, but the links are 10" + wear allowance + the hooks.

[Talltim]

In the US, where Kadees are a pretty good representation of the prototype couplers, I can understand why you might want to remove the trip pins for a better representation of the real thing. If you are using them in the UK, for vehicles that don't have a buckeye in real life I think leaving the trip pins on for automated uncoupling is the better option. After all, if you want to uncouple manually, why not just use 3 link/screws?

 

I'm currently converting 36 HAAs and a dozen vee tanks to Kadees to run on our club layout at shows.

 

Are you doing the whole rakes, or just the end vehicles? For block trains I would just put them at the ends and put screw couplings in the middle of the rake, or maybe split the rake to have shorter blocks to allow shunting. Unless the rake needed to be split in certain places for loading or unloading, I'd probably go for three blocks of 10, one of 5 and a single HAA with Kadees on both ends. You could then easily remove this one when it is red carded with a hotbox!