Limited Edition models by Bachmann - slack coupling mounts.

[sigtech]

Hello everyone, I am searching for some answers to an annoying problem which is continuously occurring during shunting on my layout.

I have two "limited edition" models made by Bachmann, the B.R MK1. CCT as ( sold by "Invicta models" ) and the B.R. MK1. Horsebox ( from TMC ), and although they are well made and very detailed models, the tension-lock coupling mounts seem very sloppy and imprecise, giving rise to inaccuracies in height of the nem pockets, which in itself is made worst by the sprung extending and pivoting arrangement that is used on each mount for traversing sharp curves!

I have fitted modified (B.K) pattern tension-lock hooks, made by P.H. Designs, activated by underboard magnets,these are a direct replacement for the original Bachmann hooks but  hang so low, that they foul on the switch blades of points, causing derailments and uncoupling- along with multiple attempts to couple up due to their different heights. Does anyone know of a fix for this?

Would gluing the mountings in a fixed position work?

My curves are 22"/24" radius, which I understand would be too tight to use KD'S reliably, hence my decision to stick with tension - locks.

 

It seems to me that quality couplings, and their reliability/accuracy of operation and alignment are the main problem area now in 00.

There appears to be a lack of quality control from both Hornby and Bachmann, with some of the products exhibiting marked differences -  even when they are from the same manufacturer...

Ironically the older, more solid tension - lock seems more reliable...but very obtrusive.

 

I am beginning to wonder if the answer will eventually be to go through all my stock, and weed out any item that shows problems with coupling/uncoupling. (that will certainly solve the surplus stock problem...!.)

 

Regards

(SIGTECH ) Steve).

[HLT 0109]

Steve,

 

I have no experience of the wagons you are having difficulty with but have had problems with drooping couplings.  Is it the NEM pockets that droop or is it the couplings within the pocket?  If it is the latter, you may find that a sliver of plastic card wedged between the bottom of the coupling and the inside face of the NEM pocket effects a remedy.  Indeed, even a sliver of paper has worked on some of mine.  I have no suggestion if it is the pocket that droops.  AS far as Kadees are concerned, I use them satisfactorily on my layout with 2nd radius Hornby curves and crossovers using Hornby set track points - with care I can propel six Backmann Mk1 coaches through the crossovers.  Shorter stock, like those you refer to, should should cope even better.  I hope you manage to resolve it without abandoning the rolling stock in question.

 

Harold.

[sigtech]

Hello Harold, - it's the actual nem mounting pockets that are drooping, due to  them being mounted on sprung loaded extending arm that swings in a small arc to allow sharper radius curves (I assume) to be traversed, both are 4 wheeled vehicles - and one (CCT) is quite a long wheelbase, the droop is more pronounced at one end - I wondered if gluing the arms rigid would still allow enough travel for it to work o.k....

 Steve.

[TheSignalEngineer]

I have had several wagons like this. Usually it is the triangular bit on the back end which is a slack fit in the mount. My answer on most has been to turn the wagon upside down and put a drop of superglue on it, keeping it upside down until it has gone off. This will allow the hinge to still operate normally.

[HLT 0109]

Actually, if you prize out the pocket from its mount, you may find turning it over works.  As I remember it, the top and bottom of the triangular bit are different and it may push further into its mount if turned upside down - or it may wedge into the mount more firmly.

[TheSignalEngineer]

Actually, if you prize out the pocket from its mount, you may find turning it over works.  As I remember it, the top and bottom of the triangular bit are different and it may push further into its mount if turned upside down - or it may wedge into the mount more firmly.

The tolerances on the triangle and socket mean that some may be slack and others tight.  Also the pocket walls are not the same thickness on the top and bottom and one side has a small protrusion on it. Turning the pocket over may alter the height of the coupling slightly.

[philsandy]

I have had a few Bachmann couplings that were a slack fit in the "dovetail" pocket.

I cut a small piece of PTFE tape (approx. 10mm sq.) and placed it on the pocket, so when the coupling is pushed in it gives a nice tight fit, then just tidy up by trimming the excess PTFE tape.

 

I use the same magnetic uncoupling system (the Brian Kirby invention) and for it to work successfully the couplings must all be exactly the same height, (I even made a gauge to set them all the same) if not, the problem is not that wagons won't uncouple, but that they do, when you don't want them to, ie. when pulling stock at slow speed over the magnets.

Edited July 7, 2016 by philsandy

[34theletterbetweenB&D]

...My curves are 22"/24" radius, which I understand would be too tight to use KD'S reliably, hence my decision to stick with tension - locks...

 

Kadee: appropriately mounted these will work coupled up down to the smallest radius the vehicle will negotiate. The problem is the side buffers on our stock which means for small radius curves mounting forward of the bufferbeam or a very long coupler shank is required to give clearance. Auto coupling and uncoupling capability ceases below a certain curve radius, never been concerned enough to actually define this.

 

...It seems to me that quality couplings, and their reliability/accuracy of operation and alignment are the main problem area now in 00.

There appears to be a lack of quality control from both Hornby and Bachmann, with some of the products exhibiting marked differences -  even when they are from the same manufacturer...

 It has to be faced, that the HO 'NEM coupler pocket' and associated mountings and mechanisms was introduced to UK product with little apparent thought for the fact that it has a measure of incompatability with the tension lock coupler.

 

Considered as a unit in isolation, any particular manufacturer's execution of their design of the minature tension lock (MTL) works very well. Rigidly mounted at consistent height it is reliable. Mix brands, and even worse put them in mountings - such as the NEM coupler pocket and camming mechanisms  - that droop or require the coupler to provide centralising restoring force, and operation is a lottery.

 

I use only one brand of MTL, and modify every RTR mounting to deliver the coupling reliability required. That also ensures that the Brian Kirby mod works reliably.

 

Where an appropriate coupler choice is made for camming coupler mechanisms, these operate reliably without modification: these are coupler patterns that form a 'rigid bar' link between the mechanism. My choice has fallen on the Roco pattern, compatible with Hornby's R8220: these two items between them supply the adjustment required to overcome the inaccuracies in implementation of some of the camming mounts. 

[sigtech]

Hi everyone, just to clarify - the actual tension-locks are held securely and level in the nem pockets, the problem is the general slackness and drooping in the pivoting and extending mountings fitted below the vehicles, which have the nem pocket as part of their construction.

As you can see from the pics - the bottom of the coupling is at/just below the railtop height, too low,(by at least 2mm) and they slope forward from the bufferbeam.

Regards

Steve.

[steveb860]

Pack it with a sliver of thin plasticard.

[Dunsignalling]

I've fitted KDs to both these models but decided the CCU was more trouble than it was worth. Too much slack in all directions.

 

Having removed them, I just built up some mounting blocks out of plastic strip and fitted Kadee #141 couplings to allow for the fishbelly headstocks. Most vehicles with straight-bottomed ones will require the #146.

 

Kadees like these work well on curves as tight as 24" in my experience. Set them up so that the inside face of the knuckle is in line with the buffer face to begin with. You can attach the whole unit with double sided tape and adjust it easily. Bear in mid that the Kadee will droop a tad until the lid is secured so just concern yourself with the length at first.

 

That should be OK for hauling pretty much anything but you might experience problems propelling through 24" crossovers with longish vans like these. If so, just mount the couplers a bit further out.

 

Experimenting is cheap because you re-use the expensive part of the coupler but can buy replacement boxes (#242) in packets of 20 at very modest cost.

 

John

Edited July 9, 2016 by Dunsignalling

[D9020 Nimbus]

Remember when using Kadees that the coupler height is still important—especially if you want to use magnetic uncoupling. A sagging coupling will be problematic. There is a height gauge you can use to check it.

[Grimbling]

I may be late here, but I fitted Kadee couplings to a Bachmann BR horsebox, and yes, the couplings drooped. So, not wishing to destroy a perfectly good chassis,I bent up a THIN brass rod to support the coupling at the right height. On its roof the coupling sits at the correct height which is where I set it. Works for me. Be warned, the wire support needs to allow the coupling block to swing. Trial and error! DON'T do what I did, some superglue crept into both wheel cutouts, which stopped the wheels revolving...Doh! Out with a Dremel. Superglue dries hard....