STUART MODEL ENGINES

[Tel]

Hmmmmmm ...... Just don't do wot I did - I put the Stuart Beam on 'hold' while I did something else - took me 17 years to get back to it

[lancelot]

Hello Folks,
back on the road again with the ''SCORE'' ,
cylinder and valve assys, almost complete, working on redesigning crankshaft.
Does anyone know of a source for ''ONE SIZE SMALLER''
7BA nuts within the u/k,
All the best for now,
John.

[ron]

John,
I've bought 'one size smaller' from the supplier below [no connection]
EKP Supplies
The Old Workshop
Bratton Fleming
Nr Barnstaple
North Devon
EX31 4SA
Tel/Fax: [phone]

[e-mail]
www.ekp.supplies.btinternet.co.uk

Ron

[lancelot]

Thank you Ron for the reply, I deal with them quite a lot , but do not think that they do one size smaller nuts, they definitely do in bolts, my problem is I am building a Stuart and Turner ''SCORE'' model engine and if you stick to the drawing dimensions and pitch in the holes for the cylinders to body frame there is not enough clearance for the 7BA nuts, even with quite a lot of fettling of the body casting , it is quite difficult to get the nuts on,so I hope you can see the problem.
All the best for now,
John.

[gwrfan]

Hi John,

Well, yes they do do 1 size smaller nuts in steel, but only up to 6BA. Just checked the latest catalogue (Jan 2006).

Geoff

[steammadman]

Lancelot,
I usuallykeep a supply of hex ,steel, brass , and stainless in stock,then i am never,
well ,hardly ever stuck for any special size of nuts or bolts.
Most of the usual suppliers keep a good selection in stock.

[lancelot]

Hello folks,
well that is part of the problem, getting suppliers to obtain the correct dimensions of material to make ''One size smaller'' nuts in the size I require to make. Some times I think I should move across that strip of water , it might be easier. Here in ''NORN IRN''
it is kind of difficult to obtain what is needed to build a model.
All the best for now,
John.

[Tel]

Supplies of 'one size smaller' nuts are hard to get here as well. You might have to do wot I do & buy (shudder) some 8BA nuts & drill 'em out & tap 'em 7BA.

It's not as bad to do as you might think - thread about 6 or 8 of 'em on a bit of clearing size rode held in the drill chuck, make sure they are all bunched up with the flats aligned, run 'em into the opened 3 jaw & grip 'em with that, replace rod with 7BA tapping drill, run that thru', follow with a tap, back it out, replace with rod, run it in & release chuck, back out & wipe 'em off into a container, load the rod & go again. You can do it a lot quicker that I can write about it

[ron]

Sorry John, when I think of it was one size smaller 7ba bolts I bought from them, just assumed they would do nuts as well

Ron

[lancelot]

Good idea Tel, must try doing that, I should be able to hold quite a few in the collet chuck.
All the best for now,
John.

[lancelot]

P.S.
Just found out ''G.L.R.'' have the one size smaller ..7ba. nuts, saves me making them.
John.

[lancelot]

Hello all,
here is one for the technically minded amongst us, I am nottt, included.
I saw a reference to a STUART TURNER ''Triple Expansion'' marine engine, not capable of being run on ''AIR'', if this is so, can anyone explain in simple terms ''WHY''
I would dearly like to try that build at some time.
I gave the 10v a full test run on ''AIR'' on Friday, and she ran like a sowing machine, great to see. Only one small fault which I could not see until run on Air was a ...Very... small pin hole in the ''dome'' of the steam chest,where I had taken a little too much material off, it will fix easily.
All the best for now,
John.

[Tel]

Congratulations John, I can still remember the buzz I got (and the engine made) when my ST 10V first ran on air way back then (about 1980). The engine is still running fine after many, many hours of heavy running on both steam & air and it has done quite a few 8 & 10 hour non stop runs.

As to your question, I suspect that they reason that was said is that air will give up most of it's enery (in the form of expansion) in the first (hp) cylinder, very little left for the middle (ip) cylinder & non for the LP. Tho' by no means an expert, I'ce seen it writ that even a double expansion will not 'compound' correctly unless the intitial steam is above 120psi - WAY more than I ever run

[lancelot]

Thank you for explaining how that ''running on air'' would not work for that one, I can see at some time in the future I am going to have to ''Build a Boiler''...aarrrghhh!!!
I think that I have cracked the build of the Crankshaft for the SCORE, slightly lower melt point solder,new gas cylinder, and a new brazing hearth [It all helps] when set up with bearings in sole plate, along with a Clock Guage and a little gentle persuasion with a rubber mallet it's running fairly true.
Managed to win a half built ''TICH'' on e/bay, complete with a brand new, certificated [1982] boiler ex/ KENNIONS, ''now that going back a bit'', was lucky enough to get the lot for much less than a new boiler would have cost me, so I might have to give some thought to trying boiler building.
Al the best for now,
John.

[alanstepney]

Like many others, I built a 10V. Way, way back in time, and it still runs OK.

I am surprised they have dropped the forged crankshaft as that is the best way to make them. Although that hardly matters on such a small engine.

Talking about that crankshaft, when I made mine, I set it up according to the book, and all went superbly, up to the point when I did the final cut to finish it.

That is when I discovered how they make preztels!!

As I lived quite near, I popped in to Stuart Turners and put it on the counter. Much amusement, but they then gave me another one, free of charge. Plus a lot of useful information.

[lancelot]

Hello All,
now on the last lap of the ''SCORE'' and setting up for an ''AIR'' test. am I correct in that the air pressure line goes on the ''STEAM CHEST'' side of the engine pipework.
Could someone clearly explain the setting of the steam chest valve timing to me, verbally or by diagram, preferrably both, as I am obviously doing something wrong, I think part of the problem was that I had inadvertantly fitted the air pressure line to the exhaust side, therefore lifting the valves off the seats in the steam chests.on connecting it on the intake to steam chests, it tried to go ''A BIT'' but the pistons seemed to be fighting one another, granted the connection was not verv good on the intake side '' pipe only held on by hand '' reason being I will have to make a proper adaptor to fit intake side.
Any help or advice would be appreciated.
All the best for now,
John.

[ron]

Hi John
I've never done a two cyl engine but here's how to do it for a single.
With the steam chest cover off turn the engine over gently by the flywheel and adjust the position of the slide valve by screwing the rod in and out till both outer ports are exposed by the same amount when it's turned through a full revolution. [the inlets are the two outer ports, the exhaust is the central port]
Next set the valve timing, slacken the screw on the eccentric, turn the flywheel in the running direction and stop it at the end of it's stroke, rotate the slackened eccentric, let the slide valve pass it's port, as it comes back as soon as it starts to expose the port lock the grubscrew, continue turning the flywheel and check it exposes the port the same at the other end, if not adjust it to split the difference.
It is actually a lot easier to do than explain and for a twin cylinder it should really only be a matter of doing it twice??
The connection on the steam chest is usually the inlet on small ST engines, the exhaust is on the cylinder.
Good luck,
Ron

[Tel]

ron said:

Hi John
I've never done a two cyl engine but here's how to do it for a single.
With the steam chest cover off turn the engine over gently by the flywheel and adjust the position of the slide valve by screwing the rod in and out till both outer ports are exposed by the same amount when it's turned through a full revolution. [the inlets are the two outer ports, the exhaust is the central port]
Next set the valve timing, slacken the screw on the eccentric, turn the flywheel in the running direction and stop it at the end of it's stroke, rotate the slackened eccentric ALSO IN THE RUNNING DIRECTION, let the slide valve pass it's port, as it comes back as soon as it starts to expose the port lock the grubscrew, continue turning the flywheel and check it exposes the port the same at the other end, if not adjust it to split the difference.
It is actually a lot easier to do than explain and for a twin cylinder it should really only be a matter of doing it twice??
The connection on the steam chest is usually the inlet on small ST engines, the exhaust is on the cylinder.
Good luck,
Ron

That about covers it Ron - but always rotate in the desired running direction - both the flywheel and the valve eccentrics. As you say, treat each side as tho' it was a single engine & it will all fall into place.

[lancelot]

Hello Ron and Tel,
thank you for the advice, I will now proceed to make a connector to fit the air line to the intake side of the engine, the grub screws on the eccentrics are only slotted head, I will replace them with next size up ''ALLEN'' grubs for better grip on shaft, I will let you know how I am getting on.
All the best for now,
John.

[ron]

Hi John
A tip from an old Tubal Cain book, he advocated putting a groove right round the shaft to stop the grub screw making burrs, then you can play with the timing to your heart's content.
Ron