Mary Beam Engine Completed

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Bruce W-S
Project of the Month Winner
Jan 30, 2015
Reaction score
Perth Western Australia
The Mary Beam Engine, this engine came to me as a box of parts
that had been part machined by Wallace (Wally) Sutherland who was a
toolmaker living in Portknockie in Aberdeenshire, Scotland. He started making the Mary in January 2001 and worked on it until the diagnosis of his cancer in early July 2001. He then stopped working on the Mary while undergoing some very aggressive treatment until he finally succumbed to the disease in January 2002. The model Mary, with most of the unmachined machined components remained untouched until his wife, Mary Sutherland, sent the parts to her son David in Australia in 2013. He sought, unsuccessfully, someone to finish the model on the families’ behalf for 2 years until receiving a recommendation to myself in April last year. The part machining completed by Wally was of the highest standard and it was a pleasure to finish the remaining parts and assembly taking just over 150 hours to complete.

The engine was a Tubal Cain design from 1977 and incorporated a single
cylinder with a three-inch stroke by three quarter inch diameter piston. The valve linkage arrangement was classical for the period and the flywheel was eight inches in diameter. Except for the beam, all of the other components were fabricated.

I machined the base from 25 mm thick aluminum from an “X” class loco and
similarly the flywheel was machined from aluminum plate. Making the links for the parallel motion, governor and control valve tested my patience because of their small size however, when finished, the engine ran faultlessly with a steady exhaust beat.

The second engine is a rough copy of a Stuart No4 made form bits and pieces from the scrap box. I made the engine for a friend who had always wanted one.

My current project is building a single cylinder true diesel engine. The basic engine is complete however, making the fule pump based on the clasic CAV design has been quite difficult because of the precision required. I have not come accross anyone else who has built one so that creates the chalange.The same can be said for the injector.

Here in Western Australia you can count model engine builders on one hand with the odd finger missing so you are almost on your own and have to be creative in tool making and machining in general in order to make small parts.

Photos attached (I hope)

Bruce Weir-Smith
Western Australia



Congratulations both on your superb workmanship and your understanding of the situation when a loved one is taken from a family.

The family will treasure what you have done.
Superb machines. Thanks for sharing.
Beautiful completion and finishing of a family treasure. I'm sure they will be very pleased.
The bottom pic looks like a different engine?:confused: Or am I not looking at it right?
Great work! Will be truly appreciated I am sure.

p.s. glad my trapeze was still up, so i could hang from ceiling to view pictures correct side up!!;)