Office of Steam Logo_1

Author Topic: Refurbishing a model steam engine with a Scotch yoke transmission.  (Read 151 times)

Tony Bird

  • Full Member
  • ***
  • Posts: 582
  • Tony Bird
  • Location: Cardiff, South Wales, UK
Hi,

One day a week, most weeks, a friend visits and I give him a hand repairing/restoring one of his models.  The latest model that we are playing with is a little unusual as it uses Scotch yoke transmission for both piston and valve.  Mostly Scotch cranks are used on pumps but I do own a model steam engine that uses one for the piston the valve gear having conventional slip eccentric. Using a Scotch crank gets rid of the connecting rod so making the engine/pump more compact.

The model is scratch built, probably an own design, using materials to hand.  It isn’t very well made but who knows what machinery was available for its construction.  It was, we think, designed as a marine engine being mounted on a mahogany plank along with what might have been propeller shaft bearings.

My friend wants to use as much as possible of the original model in the refurbishment of it. A bit extra work but I think most of it will be able to be used; famous last words?

Very little of the model is square so it has been decided to reposition the parts of the engine on the original base plate, this will probably that some of the holes will have to be plugged while others just filled with epoxy.

The photographs show the model being taken apart, the last two being of how far we got in the first session, as yet only new holes have been drilled to fit the cylinder columns.

Take care Tony.

[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ] [ Guests cannot view attachments ]