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[Jasonb]

Not done one with a round trunk guide, the Tidman would be about the nearest but that was a lot bigger "box" section with flat surfaced crosshead guides.

Infact the 10V that Brian is looking at could be done very easily with the two sloping parts cut from tee section, you would not even need to do any bending.
1. angle cut bottom
2. cope cut vertical to fit the trunk guide at the complementry angle
3. taper sides
4. cut web to shallow eliptical profile.

The main reason for using tee section is it means there are less bits to hold together while soldering but at this size if tee is not available it could easily be milled from a bit of 3/4 x 3/8 flat bar.

[Gas_mantle]

Thanks, I envisaged soldering the web but using T cross section makes more sense - I'd like to give it a try but possibly cut the sloping web as a straight line to simplify things a bit :-)

[Brian Rupnow]

The base casting for this engine is only 5/8" deep, and as a consequence, both the flywheel and the crankshaft extend below the bottom of the base. This makes it necessary to use a built up sub base with the engine as designed, to give clearance for the crankshaft and flywheel to rotate. I have kept all of the features of the upper surface, but extended the "skirt" another 1/2" so no sub base is required. The original base casting had sloping sides, partly for ease in casting the part and partly for "aesthetics". I have opted to make the sides vertical for ease of machining. This will have no impact on how the engine functions.

[Johno]

Hi Brian,

The cad drawing of the engine depicts  a Stuart D10 with the optional reversing gear. If you want to build one why not purchase a Casting kit(s) from Stuarts (approximately £160) or alternatively just the drawing at £11.40. Or am I missing something here, is it the challenge of building something without using casting that is the appeal ? In my very humble opinion the D10 is one of most attractive steam engines especially with the added interest of reversing gear and or feed pump. Here is photo the one I have just completed.

regards

Ian

[Brian Rupnow]

Johno--I have no desire to buy a casting kit. The whole reason for doing something like this is to improve my machining skills and the joy of machining. It might even possibly show others that they can make quite a respectable engine without having to lay out a lot of money for a casting kit.---Brian

[Brian Rupnow]

The only other radical departure from the "casting style" is the connecting rod. On the left you can see the original "as cast" connecting rod and rod cap. On the right is the same con rod and cap machined from solid. Now remember, I have shown the "machined" con rod with no radius on any of the sharp corners. If you wanted to, for "aesthetics", you could file  in any number of nice radii on the machined rod, but other than for "pretty" they aren't really needed.

[Rumpole88]

Hi
I'm new to this site and model Engineering, I am a printing engineer by trade and I am planing to build a Stuart 7A vertical engine without buying any expensive castings. I was pleased to read your threads to hear other enthusiasts have the same idea. I have purchased the drawings for the engine and plan to fabricate the parts and find your posts helpful. Many thanks. Andy

[Brian Rupnow]

There was one more change. The original cylinders had sheet metal lagging around them (and probably insulation between the cylinder body and the lagging.)  Since I will be running this engine on compressed air instead of steam, it is much easier for me to do away with the sheet metal lagging and make the outer body of the cylinders the same shape as the lagging used to be. I have also changed out the original bolts and nuts to all #5-40 socket head capscrews. I know this last step with the bolts will have many of the purists squealing in agony, but I like the socket head capscrews much better.

[Jo]

It might even possibly show others that they can make quite a respectable engine without having to lay out a lot of money for a casting kit.---Brian

Often as not buying a casting set is cheaper than buying bar stock to make an engine out of and takes less time to machine

Jo

[Johno]

Manufacturing a component from bar stock clearly requires good machining skills. Equally, choosing the most appropriate method holding a casting, the sequence of the machining operations is part of fun when working with castings. Also, an engine made up of predominantly castings has a look and feel about it that to my mind follows full size practice and hence the appeal. Model Engining is a broad Church, each to their own. Good look with your engine, socket head screws and all, which I am sure will look the part given the 'all over machined' look, the important thing is for us all to enjoy what we are doing.

Ian

[10KPete]

I'm just tappin' me foot waitin' for the talking to stop and the chips to start flying.... Brian always has an interesting way of doing things. I love "not normal"....

Pete

[Brian Rupnow]

Jeez Pete--That's the nicest thing anybodys said to me so far today---
So--To build this, I can use brass, steel, or a combination of brass and steel. The round center portion can be either material with no penalties. The legs are going to be nasty to cut the half round in where they mate to the cylinder. Since brass is so much easier to machine than steel, I see the legs as definitely made from brass. The feet can be either metal, again with no penalties.  I have all of the material in stock to make it this way. I'll have to think a bit about the round part--I have the material for it in steel but not in brass.

[ChuckKey]

The only other radical departure from the "casting style" is the connecting rod. On the left you can see the original "as cast" connecting rod and rod cap. On the right is the same con rod and cap machined from solid. Now remember, I have shown the "machined" con rod with no radius on any of the sharp corners. If you wanted to, for "aesthetics", you could file  in any number of nice radii on the machined rod, but other than for "pretty" they aren't really needed.

The big-end of your 'machined' con rod is shown as turned, so why not turn the whole thing while you are at it, and make it look more conventional. To do this, you are just left with a little filing (another good skill to practice) where the turned exterior of the forked top meets the gudgeon pin bosses.

BTW, I built a Stuart Double 10 from castings getting on for 50 years ago, as my first major project, completing it in the summer between school and uni. And believe me, Brian, it taught me a hell of a lot about machining. It is sitting on the mantlepiece behind me as  I type, and I can still turn it over by blowing into the steam pipe. 

[ChuckKey]

I'll have to think a bit about the round part

We call that bit a trunk guide in English. The crosshead is the thing it guides.

[Brian Rupnow]

ChuckKey--You are right, of course. It should be called the "cross-head guide". I noticed that error as soon as I had posted, but didn't know if anybody would catch it or not.---Brian