Refurbershing Mamod cylinders

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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Refurbershing Mamod cylinders

Post by Tony Bird » Sun Apr 02, 2017 5:42 pm

Hi,

Some time ago I was given quite a number of double acting oscillating cylinders with port blocks that are used on Mamod type locomotives. The friend that gave them to me said he couldn't get them to work and if they did work it was not very well.

Only a couple of the cylinder sets were of mamod manufacture the rest were either replacement ones or from Mamod copies. Not being an expert on Mamods or their clones I don't know who their manufacturers were. A number have already been worked on and fitted to models.

A locomotives made from bits and pieces.

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A marine paddle engine.

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A stationary engine made from a clothes rail bracket.

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The engines for these models were refurbished as they were needed, it was decided to referbish the remaining engines ready for use as it would be quicker than doing them piece meal.

Some of the engines and spare parts that had been given.

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A lot of the engines had been taken apart so the first job was to make up pairs.

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Other than original Mamod cylinders there seemed to be two other types both having there port blocks machined with steam passageways.

The more common type.

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The less common type.

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Both types had issues with port size and there postion relative to the cylinder ports. These ports are visibly out of position.

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It was decided to plug the ports for re-drilling and as the new ports probably not line up with the steam passageways the port blocks were machined thinner like the original Mamod ones.

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Plugging the ports after machining. Left to right: original, drilled out for plug, hard soldered and cleaned up.

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Close up of plugged port block.

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A port block that has been re-drilled, some of the plugs can be seen.

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Four finished pluuged port blocks along with a pair of Mamod cylinders and a spare. These port blocks won't be drilled yet as they migh not be used on Mamod locomotives but perhaps on a model with a different port/trunnion centre distance.

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Taking the cylinders apart next.

Regards Tony.

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LNR
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Re: Refurbershing Mamod cylinders

Post by LNR » Mon Apr 03, 2017 12:09 am

Another typically thorough job Tony, the engine made from the clothes rail bracket is artistic genius, even the name "The Gourmet Rack".
Grant.

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Re: Refurbershing Mamod cylinders

Post by Tony Bird » Mon Apr 03, 2017 9:02 am

Hi,

With the port blocks ready for futher work a pair of cylinders was taken apart. As, as yet there is no use for the cylinders they will be left apart until a use is found for them when they will be altered to suit the job along with their port blocks. This usually requires the ports in the cylinder to be increased in size.

Taking the cylinders apart. The cylinders piston rod is gripped tightly in a vice with soft jaws, and a rod in this case a drill is put in the hole of the big end.

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A claw hammer is used to leaver the big end off the piston rod.

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To remove the front cylinder cover a stepped bush is made with a hole slightly larger than the cylinder cove.

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The cylinder is rested on the bush and its piston rod hit with a hammer so removing the front cylinder cover.

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The rear cylinder cover is removed in the same way by using a brass rod inside the cylinder resting on the piston The parts of the cylinder ready for further work.

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Further work will be done when the cylinders and their port blocks are required for a model.

Regards Tony.

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Tony Bird
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Re: Refurbershing Mamod cylinders

Post by Tony Bird » Mon Apr 03, 2017 9:13 am

Hi Grant,

Glad you like the model, as well as the Mamod type cylinder and bracket the pulleys/flywheel, bearings and base board were used from two laboratory pulley demonstrators which along with the bracket were bought from a bits and pieces stall at a model show.

ImageImage

A video of the engine running on air is at:

https://youtu.be/0mbQXqebztQ

Regards Tony.

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Re: Refurbershing Mamod cylinders

Post by LNR » Mon Apr 03, 2017 9:42 am

That's a very smooth engine. One video leads to another. Wondered what your wife thought of you cutting up her silverware for "Making a pair of steam engines" :shock: ;)
Grant.

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