Below is a comment from DOGA ( Double 0 Gauge Association) concerning Coupler
standards:-
As you may recall , we DOGA, formally adopted some standards for coupler
mountings at the AGM, following discussion on the forum. I've now actually
got round to sending something out to notify the rest of the world:
Quote
In recent years there has been ongoing internet discussion about coupling
compatibility in OO , and in particular about the implementation of NEM
coupler pockets . At the moment the height at which they are fitted (when
they are fitted) varies on diffferent items of RTR stock, which means they
fail to meet their objective of allowing an alternative type of coupling to
be substituted by a simple swap. There have been calls for a standard to be
set , to ensure consistancy and compatibility.
At our AGM a few weeks ago , The Double O Gauge Association formally
adopted standards for coupler pockets and sockets. These are taken directly
from the standards for HO established by the Continental "Federation of
Federations" , MOROP, in its Normes Europeennes de Modelisme (NEM), under
data sheets NEM362 (coupler pockets) and NEM363 (swallow tail socket)
The figures are:
NEM362 ("NEM pocket")
A (width of pocket) 3.2mm
B (height of pocket) 1.75mm
E (depth behind buffer face) 7.5mm
F (depth of pocket) 7.1mm
n (height from rail to top of pocket void) 8.5mm
It is of course value "n" , the height at which the pocket is set, which
has been the big issue with OO RTR.
NEM363 ("Fishtail socket")
Values of data sheet NEM363 adopted.
Given that some OO RTR vehicles now carry this type of coupling mount (eg
Bachmann 16T minerals, inner ends of Bachmann Turbostars) it seems sensible
to adopt a standard to cover this in 4mm before any problems arise
At the same time it was agreed to adopt a standard for axle length of 26mm
over pin points . The difference in axle lengths between Lima and Heljan
stock and everything else available in Britain has been a source of
inconvenience for some years
These standards were adopted by unanimous vote at the meeting following
consultation with members
There has been previous debate on the internet as to whether it would be
appropriate to adopt the HO values or whether some other figure should be
chosen for the height of the pocket. A number of factors have led DOGA to
adopt the HO mounting height of 8.5mm.
Firstly , a large majority of the British outline OO models fitted with NEM
pockets have them set to a height of 8.5mm above the rail. To adopt this
value means the fewest possible existing models are incompatible with the
standard. To have chosen any other value would have made most models
currently fitted with NEM pockets incompatible.
Secondly, probably the most popular alternative coupling likely to be used
in an NEM socket is a Kadee. The great majority of those using Kadees on
4mm stock set them to the same height as for HO - if only because the best
and easiest way to get a consistant height is to use the readily available
Kadee height gauge for HO
Thirdly NEM362 lays down the same height of 8.5mm for pockets in both HO
and S scales. Since 4mm scale lies between the two , the same height of 8.5
mm should logically be chosen
DOGA is in the process of generating datasheets covering these standards ,
which will be placed on our website in due course. These will set out the
full details including tolerances.
Thanks are due to one of our members resident in Germany, for
establishing contact with MOROP via the main German Federation , the BDEF,
in order to gain permission to clone the standards and borrow the artwork
from the datasheets for use in our own data sheets. I understand NEM362 was
originally a project of the German Federation.
We hope these new standards will help resolve this issue
Stephen Siddle, Treasurer DOGA
