Preferred height for Kadee couplers on UK 4mm scale models

[47137]

I work in engineering where it is sometimes said we love our standards - that's why we have so many of them. Kaydee specify a standard height for their couplers, a centre line 25/64 inch above rail level - say 9.9 or 10mm. This sounds like it should be really simple for everyone (including the main stream manufacturers) to adopt.

 

Some years ago I converted some RTR wagons to use Kaydees and found that the NEM sockets on most of them (especially Bachmann) were about 1mm too high. I chose to reset the coupler pockets to give the "proper" 9.9mm, and pop in a Kaydee no. 18 or 19:

 

 

I want to convert some more models. It is easy to undo the modifications on coupler pockets and set them to a different height ... but once I start cementing Kaydee no.5 couplers onto underframes they will be stuck forever. It would be easier to accept the "too high" setting of 11mm, and just tweak the trip pins as needed to work with uncouplers. After all, I don't "need" interoperability with other people's models, and I could set up a converter wagon to take along on club nights.

 

My doubt is this. Now, meaning in mid-2013, are the UK 4mm scale modellers who use Kaydees setting them at the Kaydee height of 9.9 mm or what I might call "Bachmann UK height" around 11mm, or some other preferred height? I would feel happier if I knew I was going with the majority.

[roundhouse]

If you want to be able to uncouple over magnets then you need to set the Kadees at the correct height. Most new stock these days does have the NEM box at the correct height.

 

Ian

[ngtrains.com]

For reliable operation you need to set the kadee's to the designed correct height which is actually the height for HO scale models.

The NEM standard for the coupler socket is also an HO standard and the Kadee NEM coupler is designed to be the right height when plugged in to mounting sockets conforming to the HO NEM standard.

 

The error you are experiencing results from Bachmann inventing a standard all of their own for the coupler height.

 

If you don't want the magnetic uncoupling function you could do a Bachmann and invent your own Kadee 00 standard but it will place the trip pins to high for the magnets and if you bend the trip pins to the clearance level on the HO standard less of the trip pin will be parallel to the magnet which may reduce the effectiveness of the operation.

[brossard]

Yep, early Bachmann wagons with pockets had the height wrong.  Recent releases are correct.  It's still worth checking - the Mk1 coach pockets are not right.  The Kadee height gauge is indispensable.  It's not a big deal to retrofit wagons with incorrect height pockets with No 5 couplings.  I would second the recommendation to stick to the Kadee height standard, especially if you want to play with others.  I don't use the magnetic uncoupling method (prefering to use a pointed stick) but that's a personal choice.  It does let me snip off the trip pins - eliminating the impression that unfitted wagons have automatic brakes. 

 

John

[47137]

I looked at some of my more recent purchases this evening. These models all have their NEM 362 coupler sockets at the height specified by NEM 362:

• Dapol / Model Rail Sentinel
• Dapol cement wagon
• Hornby R6561 horse box
• Bachmann 37-980W Conflat

 

All four models also have the sockets at the specified offset behind the buffer heads. Plugging in a Kaydee no.18 immediately puts the coupler at or very near to the Kaydee height (25/64 in), and with vehicles reasonably close coupled but far enough apart to just about go round a no.2 reverse curve.

 

I am glad I went for the NEM/Kaydee standard (the HO standard) last time, if not very permanently - I wasn't sure what the manufacturers were trying to do. I have six wagons (all early NEM-fitted Bachmann) which would benefit from me re-working their coupler installations, I agree the No.5 (which I have used on a pre-NEM wagon) looks the sensible way to go.

 

I suppose ratification would be NEM 362 being up-issued to cover 00 as well as HO, S and O, but I suspect MOROP/NEM is concerned with Europe, not a scale peculiar to one of its member states. Thank you to everyone, Richard.

[Pacific231G]

Richard1962, on 29 May 2013 - 22:58, said:

 

 

I suppose ratification would be NEM 362 being up-issued to cover 00 as well as HO, S and O, but I suspect MOROP/NEM is concerned with Europe, not a scale peculiar to one of its member states. Thank you to everyone, Richard.

The UK isn't one of its member states. MOROP was set up as a pan European organisation in 1954 following the 1952 Congress of Ruedesheim in which various national associations of model railway clubs, something that Britain has never had, met to agree common standards. Because 00 scale on 16.5mm gauge track was peculiar to Britain which had no national body to represent it on MOROP (even if anyone in Britain had been interested)  it was never included. The NEMs do include scales more or less peculiar to one of MOROP's member countries. European 0 scale is generally 1/45 but the French in particular use the British scale of 1/43.5 so that is included in the standards and the Germans refer to the "industrial" narrrow gauge H0i as H0f .

 

THe coupler box defined in NEM 362 is exactly the same for S scale (1/64) as for H0 in terms of its height from the railhead, dimensions of the actual box, and how far back its forward face should be from the buffer head, so it would seem perfectly sensible to use it for 1/76 scale 00 as well. It was based on the height of the top face of the standard NEM hinged loop coupler which AFAIK was a Maerklin design as that came long before the NEM box for interchangeable couplers. The box wasn't intended for Kadees but for the various couplings that European manufacturers had introduced to improve on the ghastly standard device. Kadee simply designed a coupler for NEM boxes that would put their H0 coupler head and pin at its correct height and so really open up their European market.  Unfortunately some of the manufacturers did wander a bit from the fairly strict dimensions in the NEM 362 though that seems to be improving.

 

Because they're really about making commercially produced products compatible across Europe the NEMs only cover the main scales from Z to 10 with narrow gauge models using the track standards from a smaller scale (0m, H0e, H0i etc) They don't include 00 though NEM010 on scales does mention the "Anglo Saxon" scales based on mm/ft and American H0 is supposedly to a slightly different scale of 1/87.1 (3.5mm/ft) from the European scale rounded to 1/87 that was agreed at the 1952 congress.

Edited May 30, 2013 by Pacific231G

[Removed a/c]

I think I remember someone on here saying that if the wagon/coach has a cranked tension lock the NEM pocket is not at the correct height. 

[BR60103]

I think I remember someone on here saying that if the wagon/coach has a cranked tension lock the NEM pocket is not at the correct height. 

That may have been me. The height of the top of the tension lock matches the top of the NEM standard shank.

This allows you to replace a screwed-on tension lock (even a sheet metal one) with an NEM shank with a hole drilled in it (if the screw comes up from below).

[Dunsignalling]

There is one definite disadvantage to mounting Kadees at the higher level you suggest.

 

You will need to use a longer NEM head (19 or 20) because an 18 will foul the coupling hook on the headstock. I have had this happen even with the NEM mount lowered to the correct height because the Bachmann hooks are oversized. This creates larger gaps between vehicles than would otherwise be necessary. You could just cut the hook off but I think wagons look wrong without one.

 

Whilst they are undoubtedly convenient if the pocket is correctly aligned, I am not a great lover of NEM fit Kadees; the short pivot makes them behave slightly differently to what I call 'proper' Kadees (anything ending in a 1 or 6 on UK stock, generally speaking).

 

Unless it creates a lot of extra work, my usual practice is now to remove the NEM mount (even if correctly aligned!) and fit a 146 direct to the chassis. This also looks neater to me than the NEM option which I consider rather bulky. I replace the moulded hook with a whitemetal casting (MJT or ABS) which looks more 'scale' and avoids any clearance issues with the Kadee knuckle.

 

The linkage on Bachmann Mk1 coaches is close underneath the buffer beam and I think this may be deliberate (to stop the standard couplings rising up when over an uncoupling ramp?). However, a Kadee head will rub (more?) against the underside of the buffer beam, preventing the link moving freely as the train negotiates changes of curvature. In combination with over-generous end float, this often causes derailments.

 

The links are made from quite 'springy' plastic and (in my experience) distort under load if the train has six or more coaches. This doesn't seem to affect the original couplings much but can cause random separation of couplers (such as Kadees) that work in the horizontal plane.

 

I spent many hours trying to tame these links and correct their alignment when they were introduced but the only certain solution I have found is to replace them with the alternative parts supplied by Keen Systems (usual disclaimer). I also recommend fitting Kadees only to 'end' coaches and using Roco heads within sets; all close coupling units function best if they lock rigidly to their immediate neighbour (as when using Bachmann's optional 'pipes').

 

John

Edited May 30, 2013 by Dunsignalling

[47137]

I suspect I asked the wrong question in post number 1; but the replies all point to a Best Practice for 00, this being to adopt the standard for HO for NEM 362 coupler pockets; and (somewhat unrelated to this, but in a similar vein) to follow Kadee’s instructions for HO for their couplers.

 

I started on the wrong footing because I happened to buy some Bachmann wagons which had the coupler pockets higher than the location standardised for HO. Perhaps Bachmann had already made a few thousand offset hook and bar couplers; or perhaps they made a mistake on this wagon chassis moulding and had to compensate for it ... but I doubt they were trying to define a standard for NEM pockets for 00. Their later models are ‘correct’.

 

I do like the idea of the pocket as the basis for using Kaydee couplers because it lets you shim a coupler up or down or swap out a broken coupler. Or, you could replace a whole pocket/coupler assembly, without making a permanent alteration to the stock. For one of my Bachmann wagons I have cut down the hook of a Kaydee no. 6 coupler (metal, no offset), crushed it sideways and expoxied it into the NEM socket. This is then at the spec. height of 25/64 in. Maybe it will fail too soon (the pocket is a flexible plastic, the glue may pull out), I will wait and see. Incidentally I wouldn’t recommend the no. 6 for a standard install any UK stock with buffers, it is too short and the housing is too long.

 

For my one and only Bachmann coach (a BR Mk1) I have drilled through the shank of a Kaydee no. 20 and used a small screw to fix it to the underside of the coupler pocket. This keeps the original close coupling mechanism. It works for a one-coach train, it might be too weak for a long train.

 

EDIT: removed misleading description of fitting a coupling to a Hornby J94

 

I ran out of couplers at 5.30, just as the local model shop closed, probably a good thing for the time being ...

Edited June 9, 2013 by Richard1962

[ngtrains.com]

This topic has proved useful and basically says there is a standard, a height gauge and you should use it.

However, there is one thing we haven't got straight and had I spotted it at the outset I probably wouldn't have contributed because i'd have been busy having a rant. As a result I am going to have my rant now.

 

Can we just get one thing straight once and for all.........

 

 

Its 

  KADEE

 

Its not Kaydee, Keydee or any of the other oft repeated but WRONG versions used.

 

There are plenty of clues as to which is correct.  Try http://www.kadee.com  Or

 

 

 

 

 

 

Sorry, but that winds me up about as much as train station

[47137]

Nothing wrong with train station - its like a bus station, but with trains in it. It stopped being a railway station when the railway stopped being a common carrier. Fighting it is like saying font (typeface not baptismal) should be fount.

 

Everything wrong with Kaydee though, but at least it's only in my posts in this thread. Sorry. It might be subconscious; the wife of a friend who models US railways is Kay.

 

EDIT: It occurs to me now, this is probably why I couldn't find much on 'Kadees' on the forums :-)

Edited June 1, 2013 by Richard1962

[Dunsignalling]

I suspect I asked the wrong question in post number 1; but the replies all point to a Best Practice for 00, this being to adopt the standard for HO for NEM 362 coupler pockets; and (somewhat unrelated to this, but in a similar vein) to follow Kadee’s instructions for HO for their couplers.

 

I started on the wrong footing because I happened to buy some Bachmann wagons which had the coupler pockets higher than the location standardised for HO. Perhaps Bachmann had already made a few thousand offset hook and bar couplers; or perhaps they made a mistake on this wagon chassis moulding and had to compensate for it ... but I doubt they were trying to define a standard for NEM pockets for 00. Their later models are ‘correct’.

 

I do like the idea of the pocket as the basis for using Kaydee couplers because it lets you shim a coupler up or down or swap out a broken coupler. Or, you could replace a whole pocket/coupler assembly, without making a permanent alteration to the stock. For one of my Bachmann wagons I have cut down the hook of a Kaydee no. 6 coupler (metal, no offset), crushed it sideways and expoxied it into the NEM socket. This is then at the spec. height of 25/64 in. Maybe it will fail too soon (the pocket is a flexible plastic, the glue may pull out), I will wait and see. Incidentally I wouldn’t recommend the no. 6 for a standard install any UK stock with buffers, it is too short and the housing is too long.

 

For my one and only Bachmann coach (a BR Mk1) I have drilled through the shank of a Kaydee no. 20 and used a small screw to fix it to the underside of the coupler pocket. This keeps the original close coupling mechanism. It works for a one-coach train, it might be too weak for a long train.

 

For my Hornby J94 (screwed-on original couplings, no NEM pocket) I have taken the hook from a Kaydee no. 5 and fixed it onto the chassis with the original screw, a washer, superglue and Loctite 601.Again I am not sure; Dapol chose to put a moving pocket onto their Sentinel, but Bachmann put rigid pockets onto the bogies of their EPB. I don’t know yet whether a rigid coupling mount will be reliable on loco.

 

I ran out of couplers at 5.30, just as the local model shop closed, probably a good thing for the time being ...

The pocket mounts on Bachmann wagons are moulded integrally on older chassis (and are too high) whereas they are removable on recent models (these are OK). The old ones are so far adrift that, with sufficient packing added to correct the height, the pocket will often fall out unless secured with superglue.

 

This non-conformity with the NEM standard affects anyone who wishes to change couplings, not just we Kadee users. Far too many people have made light of this in the past, but it effectively makes a nonsense of what is supposed to be a universal 'plug-and-play' system.

 

Imagine the outcry in other areas of the forum if a major manufacturer decided to ignore a crucial aspect of the NMRA DCC standards.

 

If I need to fit a Kadee in place of a screwed-on tension-lock coupler, I generally follow the #20 method you descibe using on a coach. It also helps to pin it in place with a short piece of wire to prevent unwanted turning about the screw. Rigidly mounting any of the Kadees designed to pivot within a draft box risks impairing the magnetic uncoupling facility.

 

I, too have used modified #6 (and #7 or #16) couplers stuck into pockets occasionally (notably on the rear of Bachmann BR 2-6-4Ts) but recent converts to the Kadee may be confused by the reference as the couplers concerned are no longer produced.

 

John

Edited June 2, 2013 by Dunsignalling

[Ravenser]

It's worth pointing out that there is in fact a standard for the position of NEM pockets on 4mm stock: it's here:

 

http://www.doubleogauge.com/standards/couplings.htm

 

This was issued a few years ago, after a debate on MREMag on this issue where the general consensus of 4mm users for mounting at the HO height was being clouded and disrupted by the usual cry "there's no standard for OO so you can't say it's wrong!".  DOGA promptly issued a OO standard , which mirrors NEM362, and copies have been sent to the RTR manufacturers : I understand they have all indicated that they would follow it . Obviously models tooled before 2007 where the NEM pocket was at the wrong height are still not compliant , Bachmann Mk1s being the most glaring example.

 

For Bachmann Mk1s I've followed a tip from 34C of this forum (I think) , which is to force into the box the metal coupler head of a Kadee no5 and retain with superglue. I found it necessary to file back end of the "spade" on the coupler head (which would normally fit over the circular raised moulding in the draft box) and to hack away a little at the side of the pocket to get the coupler head in far enough. This , obviously , results in a perminantly fixed Kadee but it comes out at the right height. I've done this on outer ends (I run my coaches as 2 car sets)and used the Bachmann NEM plastic steampipes as coupler within the set. This closes up the coaches and eliminates the gap between corridor connections

[Midland Lad]

I have messed around with Kadees and three links for several years now and actually run both at both ends on some of my stock...... Is that a first? I have found Kadees do need to be set up very carefully and the height gauge is indispensable, once I purchased one of these and mounted it on a spare Peco code 100 three way point (so I can check the sticky down bit will clear everything) then the operation and set up of Kadees has come good.

 

NB I find that Bachmans NEM boxes can sag from the correct height therefore filling the gap if present between the under frame / chassis with plasti card and superglue / poly cement does the trick and prevents bending of the arm in the horizontal at the rear of Bachmans NEM box which results in more reliable and positive operation. The down side is Bachman puts the major screws to release the bodies from the chassis on most of there locos right in the same spot where the void needs to be filled...... Seems to be solve one problem then need to hack away at the mass of superglue etc to service the loco.

[Dunsignalling]

I have messed around with Kadees and three links for several years now and actually run both at both ends on some of my stock...... Is that a first? I have found Kadees do need to be set up very carefully and the height gauge is indispensable, once I purchased one of these and mounted it on a spare Peco code 100 three way point (so I can check the sticky down bit will clear everything) then the operation and set up of Kadees has come good.

 

NB I find that Bachmans NEM boxes can sag from the correct height therefore filling the gap if present between the under frame / chassis with plasti card and superglue / poly cement does the trick and prevents bending of the arm in the horizontal at the rear of Bachmans NEM box which results in more reliable and positive operation. The down side is Bachman puts the major screws to release the bodies from the chassis on most of there locos right in the same spot where the void needs to be filled...... Seems to be solve one problem then need to hack away at the mass of superglue etc to service the loco.

You shouldn't need anything as permanent as superglue or poly cement for this - just something with enough 'stick' to stop it sagging.

 

I would suggest you try Copydex instead, this is a rubbery (latex based?) adhesive that should be strong enough but will be easy to remove and clean off when it becomes necessary. Clean the surfaces to be joined of any oil (with alcohol or lighter fuel on a cotton bud) first to make sure it will stick properly.

 

I use it (among other things) to hold the roofs on coaches so I can get them off without damage if something comes adrift inside and I've never had one come off of its own accord. 

[roundhouse]

Canopy glue is a favourite with of mine for sticking things that I may wish to unstuck at some point in thr future. I It's basically a more sticky wood PVA

[ColinK]

Hi, I have used Kaydee's on my latest 7mm narrow gauge layout with reasonable success.

I'm now building a OO layount and thinking about what couplings to use, so this topic has been very helpful. I especially want 'hands free' uncoupling.

I have several Heljan diesels e.g.Hymek, where the tension lock coupling sags, as does the NEM pocket the couling is in. Indeed, some already come to a halt when the drooping coupling catches on a point. Any suggestions on how I could easily and succcessfully fit these with Kaydees at the correct height?

[298]

Just to chuck in my two' penneth (after discussing Kadee's earlier), I've never quite understood why 4mm/ft modellers would wish to adopt another standard from 3.5mm/ft modellers. Dangling the coupler that low can create mounting issues if you want to use the standard draft boxes as supplied, and I've never been too keen on the irregular mounting of NEM pockets and associated mechanism used to mount a kadee coupling into one.

 

The solution we came up with "back in the day" involved mounting a no.5 coupling box directly to the floor of a Lima coach, which resulted in a standard height of 10.0mm from the top of the rail height to the bottom of the knuckle head. Some trimming of the area around the bufferbeam and corridor connector might have been needed depending on the length of shank used, but the result looked quite acceptable with the knuckle at a scale height. The trip pin could also be used with track magnets, once adjusted.

[ngtrains.com]

How many times!!!!!!!!!!!!!!!!!!!

 

Hi, I have used Kaydee's on my latest 7mm narrow gauge layout with reasonable success.
I'm now building a OO layount and thinking about what couplings to use, so this topic has been very helpful. I especially want 'hands free' uncoupling.
I have several Heljan diesels e.g.Hymek, where the tension lock coupling sags, as does the NEM pocket the couling is in. Indeed, some already come to a halt when the drooping coupling catches on a point. Any suggestions on how I could easily and succcessfully fit these with Kaydees at the correct height?

 

 

Oh, I get it now. You're just doing it to wind me up aren't you?

[47137]

Just to chuck in my two' penneth (after discussing Kadee's earlier), I've never quite understood why ...

 

The whole point of starting this thread was to try to find out what standard the majority use; and the resulting discussion has revealed a reasonable 'best practice', all from the point of view of interoperability and ease of use.

 

There is no need to create new standards where a useful one already exists; and here we already have the same standard for NEM pockets for 1:87 and 1:64. Surely, it is only sensible for 1:76 to use the same.

[ngtrains.com]

Just to chuck in my two' penneth (after discussing Kadee's earlier), I've never quite understood why 4mm/ft modellers would wish to adopt another standard from 3.5mm/ft modellers

 

How about because no one makes a 4mm / 00 (call it what you will) version of the Kadee coupler?  Kadee make them for HO (and a number of other American scales) and I am sure they spent a small development fortune making sure they worked for that scale. To ensure they worked and that installations were repeatable and easy to do they produce a range of supporting tools such as a coupler height gauges, un-couplers and adjusting tools all set to work with the declared HO standard. It must work because there is a long list of copies by other manufacturers but the reason they work is that they are all done to the same standard.

 

So far it seems for 4mm an organisation has declared a height to use for 4mm but no one has produced a coupler to match yet.

 

The couplers will work at any height if all you want them to do is uncouple but unless you put them at the design height and set them up according to the declared standard you run the risk of compromising the auto and delayed coupling and uncoupling which is afterall why most 00 modellers will accept the incorrect looks of the coupler on UK stock

[47137]

... you run the risk of compromising the auto and delayed coupling and uncoupling which is afterall why most 00 modellers will accept the incorrect looks of the coupler on UK stock

 

Well ... I chose mine because they look so much neater than a tension lock coupler, and a brief personal foray into scale three-link ones told me I needed something automatic. As a bonus, the closer coupling between wagons is better too. I always rather liked the coupling used by Hornby Dublo, but I believe the designer or patent holder wanted royalties from users and so it faded away. If not I would have happily gone for HD. I've not used the Kadee delayed uncoupling feature yet (no layout ...), but I do think it is nice to have it there.

[298]

The whole point of starting this thread was to try to find out what standard the majority use; and the resulting discussion has revealed a reasonable 'best practice', all from the point of view of interoperability and ease of use.

 

There is no need to create new standards where a useful one already exists; and here we already have the same standard for NEM pockets for 1:87 and 1:64. Surely, it is only sensible for 1:76 to use the same.

 

I was merely offering an alternative solution based on past experience of myself and others, and must claim that I have no knowledge of the adopted heights that other modellers generally use. Once again it seems that the 4mm scale world has been railroaded into somebody else's standard when the "starting with a clean sheet of paper" wouldn't have ended up with the result that seems to be most acceptable to some. The only reason for accepting the HO standard would be for coupling compatability between the two scales, which really isn't a necessity.

 

Considering the advances made in other world markets, I think the only solution would be for a proper UK spec buckeye coupling, instead of the wrongly-handed US overscale knuckle mounted in a HO European coupling mechanism. Anyone who thinks one isn't necessary is ignoring all nationalisation coaches, modern freight vehicles, Gresley coaches, EMU's, etc....

[ngtrains.com]

I think the only solution would be for a proper UK spec buckeye coupling, instead of the wrongly-handed US overscale knuckle mounted in a HO European coupling mechanism. Anyone who thinks one isn't necessary is ignoring all nationalisation coaches, modern freight vehicles, Gresley coaches, EMU's, etc....

 

So get on and commit your development thousands of pounds and get it in production if you are so convinced its the only way forward. Assuming you are right your return will come rolling in to pay back your development, and if it doesn't you'll have the satisfactions of having been right.

 

I suspect what you overlook is that the HO standard is applied worldwide and supported by nearly all manufacturers whilst the 4mm standard is UK only and not supported by any manufacturer. At least that means the UK market it wide open for your new product. I'll buy some when you have got it done as it should couple to my 0n3 American stock.