Swallow tail type couplings

[pharrc20]

Hi all, having inherited a mixed bag of the narrow type tension lock couplings that feature a swallow tail end designed to fit into a NEM pocket I am intrigued by the letters and numbers on the underside. So far on the flat i.e. non-cranked type I have ones marked A, B, C and D then 1, 2, 3 and 4. Further sorting of the cranked versions reveals the same A-D and 1-4 markings.

Silly question time but do these denote anything? I am guessing different lengths from the straight part of the coupling over the curve front.

I am guessing most are Bachmann or even Hornby but I've no sealed new packets to compare with atm.

Just wondered cheers Paul

[ikcdab]

And are all the swallow tails the same size?  I have a Hornby schools which I want to add a coupling to the front bogie bit I can't for the life of me get the swallow tail into its recess.

[laurenceb]

Internal code to id which tool was used

[34theletterbetweenB&D]

12 hours ago, pharrc20 said:

Hi all, having inherited a mixed bag of the narrow type tension lock couplings that feature a swallow tail end designed to fit into a NEM pocket I am intrigued by the letters and numbers on the underside. So far on the flat i.e. non-cranked type I have ones marked A, B, C and D then 1, 2, 3 and 4. Further sorting of the cranked versions reveals the same A-D and 1-4 markings.

Silly question time but do these denote anything? I am guessing different lengths from the straight part of the coupling over the curve front.

I am guessing most are Bachmann...

The features mentioned are definitely present on Bachmann product. No letters and numbers on any Hornby, Heljan or Oxford tension locks I have seen to date, (not that I have closely inspected many, they come out and the Bachmann type go in, on those vehicles that are tension lock equipped).

[pharrc20]

16 hours ago, ikcdab said:

And are all the swallow tails the same size?  I have a Hornby schools which I want to add a coupling to the front bogie bit I can't for the life of me get the swallow tail into its recess.

Will find the digital vernier and measure them up once back home next Monday to find out.

Cheers Paul

[pharrc20]

15 hours ago, laurenceb said:

Internal code to id which tool was used

Ah that makes sense so maybe a different tool each a different size maybe?

Cheers Paul

[pharrc20]

3 hours ago, 34theletterbetweenB&D said:

The features mentioned are definitely present on Bachmann product. No letters and numbers on any Hornby, Heljan or Oxford tension locks I have seen to date, (not that I have closely inspected many, they come out and the Bachmann type go in, on those vehicles that are tension lock equipped).

Ok so Bachmann they must be then. I will have to inspect a new packet in the model shop next time I visit one that has some in stock to see what is what.

Cheers Paul

 

[The Johnster]

4 hours ago, pharrc20 said:

Ah that makes sense so maybe a different tool each a different size maybe?

Cheers Paul

Don’t think so, Paul, though I’ve been wrong before.  Some of my Bachmann wagons have different codes on the couplings at either end, though the couplings appear identical.  

 

AFAIK Bachmann make 4 types of NEM couplers, long or short straight,  and long or short cranked (the coupling pocket is stepped downward ahead of the swallow tail) to cope with different mounting positions in terms of distance proud of the buffer beam and of height.  

 

Couplers have to be mounted on rigid framed or bogied vehicles and a variety of situations on locos, so there cannot be a standard mounting position for the dovetail mounts. 

[dasatcopthorne]

I've swapped lots on Hornby couplings for the Bachmann one as I use the Brian Kirby method of magnetic uncoupling. (the Bachmann hooks are non-magnetic)

 

I have found that there is absolutely no difference in the numbering and lettering on same size/style units.

 

Dave.

[ejstubbs]

2 hours ago, dasatcopthorne said:

I have found that there is absolutely no difference in the numbering and lettering on same size/style units.

 

Really?  Back when I was planning to adopt the Brian Kirby uncoupling method I bought a lot of Bachmann short NEM TLCs and there was no knowing what letter or number each would have moulded on to it.  I could freely mix and match couplings and NEM boxes with different markings.

 

I reckon laurenceb is probably closest to the answer: it's likely a manufacturing traceability marking for Bachmann's own purposes, it doesn't indicate which type (short/long, cranked/straight) the coupling is.

 

[Bernard Lamb]

1 hour ago, ejstubbs said:

 

 

 

I reckon laurenceb is probably closest to the answer: it's likely a manufacturing traceability marking for Bachmann's own purposes, it doesn't indicate which type (short/long, cranked/straight) the coupling is.

 

Not just the closest, he is 100% correct.

I would imagine that a part that small is made on a multi cavity tool.

The identification marks are to identify which cavity a part is from.

This allows for wear on the tool to be checked and the tool taken out for repair as wear occurs.

Now if one cavity is worn a decision can be made as to whether to take the tool out or to finish the run with one cavity producing scrap.

Not always a simple answer as it depends on the size of the part and the length of the run and the urgency of the items.

We had a book at work with the expected number of parts to be made on every tool and could monitor actual tool life against theoretical tool life.

Not that important when making couplings but on over 1m parts in a week on certain items control was essential.

If you look at some plastic items you will see various marks and these are codes for the date of manufacturer as well as the tool identifier.

This can range from a "secret" code to something as simple as a clock face with a hand for the month.

 Bernard

[dasatcopthorne]

8 hours ago, ejstubbs said:

 

Really?  Back when I was planning to adopt the Brian Kirby uncoupling method I bought a lot of Bachmann short NEM TLCs and there was no knowing what letter or number each would have moulded on to it.  I could freely mix and match couplings and NEM boxes with different markings.

 

I reckon laurenceb is probably closest to the answer: it's likely a manufacturing traceability marking for Bachmann's own purposes, it doesn't indicate which type (short/long, cranked/straight) the coupling is.

 

Yes really.

 

But perhaps I should re-phrase it?

 

There is absolutely no difference no matter what number or letter appears on a coupling of the same style.

 

I know what I meant. :-))

 

Dave