Author Topic: Murdoch-Aitken "Steeple" engine  (Read 8008 times)

Offline scc

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Murdoch-Aitken "Steeple" engine
« on: September 27, 2021, 07:10:05 PM »
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  ::)
« Last Edit: October 09, 2021, 07:22:40 AM by Jo »

Offline Dave Otto

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Re: Mudock-Aitken "Steeple" engine
« Reply #1 on: September 27, 2021, 07:14:24 PM »
Hi Terry

I will be pulling up a chair and following along.

Dave

Offline Don1966

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Re: Mudock-Aitken "Steeple" engine
« Reply #2 on: September 27, 2021, 09:19:53 PM »
Yep Ike Dave I will be following you also Terry!..


 :popcornsmall:
Don



Offline Jo

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Re: Mudock-Aitken "Steeple" engine
« Reply #3 on: September 27, 2021, 09:29:35 PM »
 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

Jo

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Offline scc

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Re: Mudock-Aitken "Steeple" engine
« Reply #4 on: September 30, 2021, 08:06:56 PM »
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

Offline Jo

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Re: Mudock-Aitken "Steeple" engine
« Reply #5 on: October 05, 2021, 03:02:20 PM »
This is very new teritory for me.....small and fiddly, The drawing even shows some 14ba bolts :o

:headscratch: I found a few 12BA but not 14's. If you don't like 14BA then 1mm might be easier to come by.

 I keep wanting to make my one of these ... you have got me tempted  :thinking:.

Jo
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Offline AVTUR

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Re: Mudock-Aitken "Steeple" engine
« Reply #6 on: October 08, 2021, 11:01:58 AM »
Terry

How large is this engine? The diameter of the flywheel would be useful.

I will follow, every so often, with interest.

AVTUR

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Offline scc

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Re: Mudock-Aitken "Steeple" engine
« Reply #7 on: October 08, 2021, 08:57:20 PM »
Jo, it would be good if you made one.......I could follow along and see how it's done :Lol:     None of my usual suppliers even list 14ba, 12 being their usual limit.

 Avtur,  welcome along,  I think the flywheel is about 9 1/2 inches dia.      Terry

Offline scc

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Re: Mudock-Aitken "Steeple" engine
« Reply #8 on: October 08, 2021, 09:01:49 PM »
OH DEAR,     I have just noticed that I spelt the title completely incorrectly :embarassed: :embarassed:     It should read "MURDOCH"

Apologies           Terry

Offline Jo

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Re: Murdock-Aitken "Steeple" engine
« Reply #9 on: October 08, 2021, 10:28:02 PM »
OH DEAR,     I have just noticed that I spelt the title completely incorrectly :embarassed: :embarassed:     It should read "MURDOCH"

All sorted  ;)

Jo
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Offline crueby

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Re: Murdock-Aitken "Steeple" engine
« Reply #10 on: October 08, 2021, 10:42:49 PM »
OH DEAR,     I have just noticed that I spelt the title completely incorrectly :embarassed: :embarassed:     It should read "MURDOCH"

All sorted  ;)

Jo
Almost, the R is now there, but the K at the end should be an H?

Offline Jo

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Re: Murdoch-Aitken "Steeple" engine
« Reply #11 on: October 09, 2021, 07:36:44 AM »
 :facepalm: Done that as well.

I have just found someone admiring his set of these castings.  :thinking: He claims it takes up a large amount of his Casting cupboard relative to what it is. I am increasingly becoming concerned about the amount of space required in the house for all the finished model engines and this one is not small  :o

Jo

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Offline Jasonb

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Re: Murdoch-Aitken "Steeple" engine
« Reply #12 on: October 09, 2021, 07:42:16 AM »
Probably need to update cache as it's right in the headings down the left of page only K in the thread.

14BA are not that easily found at least if you want them in steel, I cad a quick look over the drawings and could not easily spot them so assume there ate only a few required in which case you may be better off making yourself.

Out of interest what is the date of your drawings, it could be now that Blackgates are doing the castings there have been some changes possibly as 12ba was a bit tight in places. Also awaiting to hear what the castings machine like as the old Clarkson ones had a reputation for being a bit chilled particularly the two tal thin crosshead guides, hopefully the Blackgates ones will be OK.

Overall height is about 18"
« Last Edit: October 09, 2021, 07:47:10 AM by Jasonb »

Offline Jo

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Re: Murdoch-Aitken "Steeple" engine
« Reply #13 on: October 09, 2021, 08:03:36 AM »
These are an original Clarkson  :facepalm2:  set, with the Drawings dated 1971.

Jo
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Offline ettingtonliam

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Re: Murdoch-Aitken "Steeple" engine
« Reply #14 on: October 09, 2021, 08:54:20 AM »
I first fell in love with this engine back around 1968, and had a Clarkson GA of it for many years. As with so many things, it never happened, and by the time I was in a position to build one, Clarksons had long gone. When I heard that Blackgates were supplying now, my interest was reawakened, but you lot have put me right off. All this talk of 14BA and 12BA screws! I've long had a personal rule - nothing smaller than 6BA, indeed 5BA for preference.
I shall read the build logs with interest though.