Author Topic: 1/24th Scale ME Twin Beam  (Read 5726 times)

Offline Rivergypsy

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1/24th Scale ME Twin Beam
« on: May 13, 2014, 12:46:32 PM »
And to bring another project over, here's yet another that stemmed initially from a discussion with a friend Pete by email. We'd been talking about the possibility of a true scale engine which could fit in the palm of your hand, together with a parallel discussion on beam engines, and the two merged into what scaling factor would need to be applied to the ME Beam to suit this. We settled on pulling the scale down by half to give us 1/24th with a bedplate of ~7" length. Oh, and to double it up to a twin beam on a common crankshaft too  :Lol:

This engine also appealed as it's from more George Gentry drawings, so that with the entablature I've nearly finished that'll be a pair of them. So i started converting the plans into Solidworks files, working also from a list of known errors in the plans provided generously by GWRdriver to ensure they were all caught at this stage, and so far here's where we're up to-



Working through these drawings, especially after the entablature build has generated some interesting points. From the 1922 article in ME, i know that Gentry did not actually design the entablature, but instead produce the drawings from an existing engine model discovered in a house basement. comparing the two designs side by side, taking into account areas such as the cylinder and trunk port, the column proportions and ornamentation, and the forked connecting rods, to my mind at least the entablature is where he took his design inspiration for the beam.

Anyway the plan is, as I have CNC and Pete does not, is that to get us started I'll produce what would have been the awkward castings, ie. bedplate, beam and flywheel myself, then mail then over so that we can build one each. So far the bedplates are waiting for the final side to be finished. I found what I thought was gauge plate (but as soon as a cutter touched it I realised it made gauge plate feel like plastacine - good grief is it tough...) then roughed both faces to leave 1mm all over before dumping them in a draw for a while for any stresses to come out. Since then I've finished the underside of them, and now need some machine time for the top face, which will be quite a long slow process to get sufficient detail in place. More to follow ;D

First side roughed-


Second-


And the full set-


And the first underside after finishing, which gives a nice impression of how delicate these are actually going to be-


There is a vague idea floating around, for my build at least, of building the base to show true underfloor detail. This was inspired by some photos of the Lawrence pumping engine, and whilst it will be small (very) detail, it's more than tempting... :naughty:


Offline steamer

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Re: 1/24th Scale ME Twin Beam
« Reply #1 on: May 13, 2014, 01:27:33 PM »
Very Nice!  I have always wanted to build a "to scale" model of the port engine of the USS Ohio...BB12.

I have a full set of prints for it...57 studs on the HP upper cylinder head alone!

I think making a big model of a small engine, such as this,  would be more enjoyable!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline ShopShoe

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Re: 1/24th Scale ME Twin Beam
« Reply #2 on: May 13, 2014, 03:03:30 PM »
Rivergypsy,

I want to encourage you to build the underfloor part into this project. We know that those things are there, but rarely seen. I am sure that you will do your usual and make a stellar presentation out of this. I like all mechanical objects with visible moving parts, but beam engines hold a special fascination.

--ShopShoe

Offline Dave Otto

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Re: 1/24th Scale ME Twin Beam
« Reply #3 on: May 13, 2014, 04:51:50 PM »
A nice start to another interesting project. Looking forward to seeing this one progress.

Dave

Offline ths

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Re: 1/24th Scale ME Twin Beam
« Reply #4 on: May 14, 2014, 11:15:42 AM »
Another inspiring build on the way. Thanks, and I'll be watching.

Cheers, Hugh.

Offline Rivergypsy

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Re: 1/24th Scale ME Twin Beam
« Reply #5 on: May 15, 2014, 01:01:33 PM »
Thankyou for all the kind comments - more incentive to get a move on with this one!

Well if all goes according to plan, the mill's free as of tomorrow, so time to get cracking on some programming  :naughty:



Offline b.lindsey

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Re: 1/24th Scale ME Twin Beam
« Reply #6 on: May 15, 2014, 01:11:04 PM »
Those bedplates are looking great!!  Definitely one to follow along on, I admire what you guys are doing with CNC and how well it turns out!!

Bill

Offline Rivergypsy

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Re: 1/24th Scale ME Twin Beam
« Reply #7 on: May 15, 2014, 01:25:17 PM »
Many thanks, Bill! I do love manual machining, and sometimes CNC feels like cheating, but it does let you do so much. Faster too, since you can be running another machine in the background  ;)

Just some initial thoughts, but this is an initial idea for getting the engine on to a foundation. This something like this welded fabrication in steel to tie them together rigidly, then a fitout could be done around it to show floor beams and floor boards, and then the uprights clad in stone blocks to replicate the original stonework?


Offline b.lindsey

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Re: 1/24th Scale ME Twin Beam
« Reply #8 on: May 15, 2014, 01:47:19 PM »
I agree with ShopShoe as to the presentation. It takes an already lovely engine to a whole new level, especially the beams, flooring and stone cladding. I know its heresy to talk too much about the brown stuff, but why not do the whole support with hardwood beams? I would think those bedplates properly attached to a well designed wood support structure would provide plenty of rigidity.  Just my $.02 cents and likely not worth that :)

Bill

Offline Rivergypsy

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Re: 1/24th Scale ME Twin Beam
« Reply #9 on: May 15, 2014, 02:14:54 PM »
Hi Bill,

What worries me with a 100% timber construction is that there's likely to be movement between the two bedplates which could cause the motion to bind up. Maybe I'm wrong, but I had thoughts of the moisture level in the timber (heat/damp) moving, or even the metalwork settling into the wood. I guess old habits die hard too, as it's not unknown for me to go for the 'brick outhouse' build style...

For the beams and boards I do have a nice little stash of Australian Jarrah floorboards which could do quite nicely ;D

For the model though, i do need to head-scratch how to deal with the flywheel area  :shrug:

Online Jasonb

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Re: 1/24th Scale ME Twin Beam
« Reply #10 on: May 15, 2014, 04:47:07 PM »
As you have it drawn in your sketch it looks as though the engine is sitting on the timbers. Its far more likely they would have sat it straight on the stone with the beams either in pockets or a ledge built into the stomework.

Make a fabricated frame like you have shown and clad it to look like stone then the timber floor can be independant of that and provide no structural support to the engine so not worries about movement in the wood

J

Offline Rivergypsy

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Re: 1/24th Scale ME Twin Beam
« Reply #11 on: May 16, 2014, 12:12:23 PM »
Hi Jason,

What's shown so far in the SW drawing is purely the steel guts of the base, but you're right, in the final build those piers will be clad in stone upon which the bedplates will sit, and then the beams will protrude from this as cantilevered supports for the boards. I may add a removable rear wall too, but quite how it'll work I'm not sure yet...

Dave

Offline Rivergypsy

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Re: 1/24th Scale ME Twin Beam
« Reply #12 on: May 16, 2014, 12:58:13 PM »
Well the mills free as of ~2pm and the 1st op in finishing the tops is ready. To break things into manageable chunks and not hog the machine for too long, the first op common to both left and right hands is purely profiling the base and the mounting bosses and spotting the holes off. These I can drill on the pillar drill ready for the M1.6 mounting studs.

Online Jasonb

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Re: 1/24th Scale ME Twin Beam
« Reply #13 on: May 16, 2014, 01:16:59 PM »
These I can drill on the pillar drill ready for the M1.6 mounting studs.

When you say things like that it strikes home just how small this is going to be ::)

Offline Rivergypsy

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Re: 1/24th Scale ME Twin Beam
« Reply #14 on: May 16, 2014, 02:54:01 PM »
That'll all be part of the fun, Jason  :lolb:

What did strike me when modelling the links is that the gibs and cotters come out at 0.8mm, so we may have glasses the thickness of beer bottles by the time these run...