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Murdoch-Aitken "Steeple" engine

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Just a quick intro to my next project.  A new venture for me.......castings!      My Burrell used lots of them but they were big and easy to hold. It is a good job that I have been following Jo's excellent tutorials.      I have a few tidying jobs in the shop first and then off we go.       Terry

Edited by Jo: Corrected Title Spelling  ::)

Dave Otto:
Hi Terry

I will be pulling up a chair and following along.


Yep Ike Dave I will be following you also Terry!..


 8) Nice one Terry,

Looking through my notes on this engine I found something that claims there may be a couple of drawing corrections:

The engine has two side rods connected by a bridle beneath the table. From here, a single short connecting rod goes down to the big end. As drawn, the bridle would have struck the top of the crankshaft bearing. I had to lengthen the short rod, and shorten the side rods by about a quarter of an inch. This now meant that the bridle hit the underside of the the table. The table top was duly excavated to make room. Actually, this no bad thing, as the table tops on full size table engines were assemble from five castings, and were in fact hollow.

The side rods, as drawn, would not pass the exhaust belt, of through the slots either side of the cylinder top. I kept the "fish bellied" profile, but filed flats on each side to give clearance. It sounds like a bodge, but in fact it looks quite good, and I have seen something like it in full size, just for the decorative effect.

The positioning of the little brackets that carry the shaft drive for the governor is a bit vague. In the end, I fixed mine to the foundation block, not the engine bed plate.

The starting levers are quite unlike the original drawings. With the levers in front of you, the left hand one, which disconnects the valve gear from the eccentric, is connected to the eccentric rod buy a parallelogram of levers. Lift the lever, and the slide valve is free to be moved. The right hand lever is to do the moving. It is held in the valve shaft by a taper, and could be removed for safety once the engine had started. If the parallelogram of levers, previously mentioned, are correctly proportioned, then the left hand lever does not move when the engine is in motion. I found this quite a surprise, but it means that it does not present a hazard.

Best to be aware of them before you start  ::) and I have attached some picture of the original engraving of this engine


Glad to have you following along Dave and Don, but don't expect rapid progress!   This is very new teritory for me.....small and fiddly, The drawing even shows some 14ba bolts :o
Jo, Thank You for your detailed  response.  Valueable info indeed. I'd heard rumours of drawing errors.  Those etchings are great and make the drawings much easier to follow, I have printed them off for the workshop wall and inspiration :facepalm2:

Thanks again      Terry


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