Modified Mamod couplings.

A very popular starting point for Live Steam. With their low cost comes a number of problems which can be discussed here
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Tony Bird
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Modified Mamod couplings.

Post by Tony Bird » Fri May 30, 2014 8:11 am

Hi,

Over the last couple of years after a break of many years I have done some work on several Mamod locomotives but nothing to any of their rolling stock. The alterations to make a Lagos Tram engine from a Mamod (another thread) changed this. A decision whether to retain the original couplings or fit new needed to be made. In the event the original buffers were altered to become centre buffer/coupling. This isn't a new idea I have many spare buffers from a long time ago to prove it.

To do this type of conversion for each locomotive/wagon four 6BA screws and nuts are needed to replace the buffers and hold the buffer beam on and in the case of the wagons hold them together. The original coupling needs to be removed and a 2.9mm hole drilled where it was. Alterations to the buffers; the buffer stock is glued onto the buffer head (Araldite/Loctite), a section of the buffer head is cut off to clear the coupling, a 1.6mm hole drilled through the buffer stock to take a 1/16" brass rod bent as a coupling hook which is glued in place. The coupling hook can be bent to use a loose coupling or one of the hooks can hold the coupling captive.

These couplings work very well both pulling and pushing and the original Mamod round coupling link works very well, not so their oval style one which can sometimes jam when pushing.

Hook type.

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Captive type.

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Pulling.

Image

Pushing and will easily negotiate Mamod curves.

Image

Loose coupling.

Image

The two spare buffers from each conversion can be used on scratch built wagons or as embellishments to a child's toy.

Image

Regards Tony.

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mikewakefielduk@btinterne
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Post by mikewakefielduk@btinterne » Fri May 30, 2014 10:13 am

Excellent idea and great photos. Thanks.

dougrail
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Post by dougrail » Fri May 30, 2014 2:34 pm

Great stuff Tony, cheers for the update. Glad to see you 'back in the business' - after seeing your Toucan in the steel I was left very impressed indeed :cool:

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andymctractor
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Post by andymctractor » Fri May 30, 2014 3:22 pm

Most of my stock uses chopper couplings but I have some of the buffer type with the hook on top particularly for stock hauled using Roundhouse locos. My idea is similar to yours except that I use small O seals instead of the rings you are using. The trick is to get a supply of the correct size of O seals. If you get this right the seals will allow simple coupling and uncoupling, will reduce absorb some of the snatching of couplings when a heavy train is started yet will stretch whilst holding the couplings together when negotiating sharp curves etc.
Regards
Andy McMahon

If it moves, salute it.  If it doesn't move, paint it. (RN sailors basic skills course 1968)

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Tony Bird
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Post by Tony Bird » Sat May 31, 2014 8:51 am

Hi Andy,

My idea is similar to yours except that I use small O seals instead of the rings you are using. The trick is to get a supply of the correct size of O seals. If you get this right the seals will allow simple coupling and uncoupling, will reduce absorb some of the snatching of couplings when a heavy train is started yet will stretch whilst holding the couplings together when negotiating sharp curves etc.

What a good idea I will try it.

Regards Tony.

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andymctractor
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Post by andymctractor » Sat May 31, 2014 4:21 pm

Tony Bird:101249 wrote:What a good idea I will try it.
The last time we had our heating system serviced the engineer allowed me to take a small handful of seals from his ready use supply. Trying to buy them from local DIY usually means they are in a pack containing a variety of sizes most of which are of little use.
Regards
Andy McMahon

If it moves, salute it.  If it doesn't move, paint it. (RN sailors basic skills course 1968)

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