Stuart 10v

[Steamchick]

Hi Swarf. You can - I guess, not knowing your abilities - take a 2 mm skim off the surface (or whatever) and replace with a piece of gauge plate of that thickness. I would be tempted to silver solder the plate to the surface an then mill new ports. But alternatively it can be screwed or riveted in place. Richard will know the best method. His advice teaches me a lot.
But if defective I would expect the casting supplier to replace it.
Cheers.
K2

 

[Charles Lamont]

You won't know the exact status of the ports until you have machined the port face. It is premature to state the casting is defective. There is an inevitable tolerance on a sand or shell-moulded castings that you just have to work with.

Actually, the position of the exhaust port does not matter - it does not affect timing. It would have been better to work the cylinder end faces from the outer edges of the steam ports.

Either way, the valve can be set to suit (but anyway only insofar as the 10 thou adjustment that a half turn of the 7BA valve rod provides).

The timing and sharpness of valve events on a Stuart No10 built as designed will be imperfect, but perfectly adequate. And one can of course do extra work to make improvements.

BTW, It looks good so far.

 

[Richard Hed]

You won't know the exact status of the ports until you have machined the port face. It is premature to state the casting is defective. There is an inevitable tolerance on a sand or shell-moulded castings that you just have to work with.

Actually, the position of the exhaust port does not matter - it does not affect timing. It would have been better to work the cylinder end faces from the outer edges of the steam ports.

Either way, the valve can be set to suit (but anyway only insofar as the 10 thou adjustment that a half turn of the 7BA valve rod provides).

The timing and sharpness of valve events on a Stuart No10 built as designed will be imperfect, but perfectly adequate. And one can of course do extra work to make improvements.

BTW, It looks good so far.

The port holes are not the problem, it is those two BLEMs , the two very large pits or holes on the side, I don't know what you call them but apparently the cast iron didn't fill properly. If one can drill the holes to the steam and from the exhaust without touching those holes, then all is good. Even so, I would send them back if I recieved them. That is, if they are what I THIMFPK they are. I've got the same set of castings and they do not have those holes in the side. When he drills the exhaust hole, the passage way might miss those two blems, but what about the steam input passage ways? Those passages might hit those blems too. We'll probably have to wait--with baited breath, high tension, fear and loathing, excitement and on the edge of our seats.

 

[swarf]

Lol. Don't wait to long. I'll probably play with this, but I am getting another casting.
As mentioned, the flanges at either end are not the same thickness. I don't know how that will affect the passage in relation to the ports.
In the meantime there's other parts to machine.
Thanks

 

[Richard Hed]

Lol. Don't wait to long. I'll probably play with this, but I am getting another casting.
As mentioned, the flanges at either end are not the same thickness. I don't know how that will affect the passage in relation to the ports.
In the meantime there's other parts to machine.
Thanks

Did you get those castings from Great B? (or is that the UK now?) I got two sets, the 10V and the H. Most parts are identical, but not the stand (standard) or base. There are a few lengths of rods a little shorter too. The cylinders are identical.

 

[swarf]

Richard, straight from the U.K.

 

[Charles Lamont]

Ah! I had not noticed those cavities under the port face. I have never seen a No10 cylinder like that before, but from the photo it looks to me as though it might be intentional. The shape seems too precise and symmetrical for a blow hole. The cavities are too dark in the photo to get an idea how deep they are. Perhaps a new feature to save a little iron and make the metal thickness more uniform? What does the other side look like?

 

[methuselah1]

I made my first engine from castings, a 10V, back in '93. The crosshead guide cracked when it was reamed, but when I did a 10H, a Score and a No.9 things went smooth- my first lathe was a cheap rubbish Ross and Alexander, with only one speed- 900rpm! That and a knackered drilling machine. The lathe didn't even have graduated handwheels. Everything has been upgraded now, and I'm still left wondering how the hell I did it.

Moral of the story is it's sometimes useful to NOT know what can't be done.
As to B.A. threads, Stuarts are the only kits I know that come with all the fasteners, and rather nice ones at that. This means you only need get 5,7 and 8BA taps, even then only two out of the set of three, and in carbon steel. C.S. Is actually harder than H.S.S. It just can take heat, and hand taps just don't get hot anyway. The bigger holes used to be given as 1/4" Brass Gas, but anyway, an equivalent U.N. Series can be substituted. The only other male threads are on the valve and piston rods. This is where joining a club may help may help you.

The only real problem part is the con-rod- try as I might, I never did find a tutorial on the 'net! Good luck, you are off to a flying start...I

-Andrew, U.K

 

[skyline1]

The port holes are not the problem, it is those two BLEMs , the two very large pits or holes on the side, I don't know what you call them but apparently the cast iron didn't fill properly. If one can drill the holes to the steam and from the exhaust without touching those holes, then all is good. Even so, I would send them back if I recieved them. That is, if they are what I THIMFPK they are. I've got the same set of castings and they do not have those holes in the side. When he drills the exhaust hole, the passage way might miss those two blems, but what about the steam input passage ways? Those passages might hit those blems too. We'll probably have to wait--with baited breath, high tension, fear and loathing, excitement and on the edge of our seats.

I agree, that casting does look very suspicious. The edges of those pits are rounded and shiny not square and matt which is the characteristic appearance of a "cold shut" where the metal has not filled the mould cavity properly.

I attempted a No 10 myself some years ago when Stuarts were in the Channel Islands and there were no cavities like this in my casting. However I did have other problems. Firstly the castings were almost exactly to size. There was no machining allowance at all in fact some were actually undersize to the drawings. The second problem was equally serious, the castings were very chilled and so hard they were unmachinable even carbide tools wouldn't touch them and with little or no machining allowance you couldn't do the usual cast iron thing of taking a very slow but deep cut to "get under the skin"

After attempting to skim the box bed, which actually cracked whilst trying to machine it I gave up and returned the whole kit.

I am sure this was not down to bad technique as I have successfully machined many C.I. castings including some that I cast myself.

Stuarts have been through several changes of ownership and site through the years and quality has been variable. They are usually quite happy to replace a defective casting F.O.C. though and I think this may be one.

Best Regards Mark

 

[swarf]

Well this has become my practice cylinder. Finished machining except for head bolt and steam chest holes. Good practice for drilling the steam passages. Just made a 25 deg cardboard template set the casting in the vice and it worked great.

 

[Richard Hed]

Well this has become my practice cylinder. Finished machining except for head bolt and steam chest holes. Good practice for drilling the steam passages. Just made a 25 deg cardboard template set the casting in the vice and it worked great.

It looks gooder than mine. I left a little, a few thou on each end to trim off later. I did this on a small enco piece of crap (a poor workman always blames his tools!). NOw I have a Grizz which is accurate and powerful. However, I am working again, (last year I workt 5 months to get the Lathe), to be able to get a mill. I would rather finish the flat ends of the cylinder on a mill than in the lathe as the shape is so much more amenable to the mill than lathe to cut it.

 

[methuselah1]

Nice work! Don't let yourself down when it comes to the cover studs... 10Vs with four or six of 'em each end look so naff! They're also a hallmark of the lazy machinist...

At a glance, your ports appear no better or worse than any other 10V casting I've seen, though.

Andrew

 

[Charles Lamont]

It looks gooder than mine. I left a little, a few thou on each end to trim off later. I did this on a small enco piece of crap (a poor workman always blames his tools!). NOw I have a Grizz which is accurate and powerful. However, I am working again, (last year I workt 5 months to get the Lathe), to be able to get a mill. I would rather finish the flat ends of the cylinder on a mill than in the lathe as the shape is so much more amenable to the mill than lathe to cut it.

One of the most important aspects of machining set-ups, rarely discussed on this forum, is knowing when you need geometrical accuracy, and how to achieve it. Here, the cylinder bore wants to be dead square to the mounting end face. This is best achieved by doing the boring and facing in one set-up in the lathe.

 

[Richard Hed]

One of the most important aspects of machining set-ups, rarely discussed on this forum, is knowing when you need geometrical accuracy, and how to achieve it. Here, the cylinder bore wants to be dead square to the mounting end face. This is best achieved by doing the boring and facing in one set-up in the lathe.

Thanx. It's too late for that and I did the cutting wrong. I should have bored the cylinder then mounted it on an arbor between centers but I did not do that. Maybe I should do that now, it would be easy to do. What do you thimpfk?

 

[Steamchick]

Yes. - But wait and see what others think... I am not always right! (My missus would add: because I'm a bloke!).
My preferred method is not to mount the workpiece in the chuck.
Too late for this process: but I would machine a datum face on the cylinder (Usually the base). Mount the cylinder on this face, having clocked the surface you are mounting onto as true (perpendicular to the axis of rotation of the cutter) - within the accuracy of your clock... Then pass a rotating cutter through the bore.
As this is the preferred way in Modern-day industry, to get a really good round and straight bore (NO TAPER), and how I was taught as a teenager - by a machinist who machined cylinders for aero-engines during WW2.... Not such an easy set-up as bunging a cylinder into a 3-jaw chuck then passing a boring bar through... but on 3 of 4 of my lathes (the first 3) that gave me tapered bores that needed re-boring in the mill-drill. (Not had to bore a cylinder like that on my current Chinese lathe).
Hope this helps?
K2

 

[Jasonb]

Arbor would be your best option to square up the faces to the finished bore.

As for if you were starting from scratch on a little cylinder like the 10V I would tend to hold in the 4-jaw and bore then face as I get a reasonably parallel bore but if it were a larger and longer cylinder would think about mounting on the lathe's cross slide and using a between ctrs boring bar. really comes down to what suits the job in hand and assumes you have a lathe with a slotted cross slide that is easy to bolt work down to.

I don't tend to use the mill for boring cylinders unless the part can't be swung in the lathe as I don't find it as rigid and with no power feed in Z harder to keep a nice constant feed.

 

[Charles Lamont]

Between centres if you like, but a stub mandrel held in a chuck and turned in situ may be easier.

 

[Richard Hed]

Yes. - But wait and see what others think... I am not always right! (My missus would add: because I'm a bloke!).
My preferred method is not to mount the workpiece in the chuck.
Too late for this process: but I would machine a datum face on the cylinder (Usually the base). Mount the cylinder on this face, having clocked the surface you are mounting onto as true (perpendicular to the axis of rotation of the cutter) - within the accuracy of your clock... Then pass a rotating cutter through the bore.
As this is the preferred way in Modern-day industry, to get a really good round and straight bore (NO TAPER), and how I was taught as a teenager - by a machinist who machined cylinders for aero-engines during WW2.... Not such an easy set-up as bunging a cylinder into a 3-jaw chuck then passing a boring bar through... but on 3 of 4 of my lathes (the first 3) that gave me tapered bores that needed re-boring in the mill-drill. (Not had to bore a cylinder like that on my current Chinese lathe).
Hope this helps?
K2

That's basically what I did but in a 4 jaw on the little (crappy enco, a poor machinist blames his tools, like me, allways remember that!) lathe. I had difficulty getting the ends square to the bore so I left about 15 thou in order to fix it later. But now I have the Big Grizz and will be able to easily fix that. Actually I forgot about the solution because I have been working on other engines. Thanx for the advice.

Excuse me, actually one end was quite squared up, it was the second end, after removing from the chuck that I had the difficulty with. With all this good advice, it will be a snap, I thimpfk, to fix it. Thanx to all!

 

[Richard Hed]

Arbor would be your best option to square up the faces to the finished bore.

As for if you were starting from scratch on a little cylinder like the 10V I would tend to hold in the 4-jaw and bore then face as I get a reasonably parallel bore but if it were a larger and longer cylinder would think about mounting on the lathe's cross slide and using a between ctrs boring bar. really comes down to what suits the job in hand and assumes you have a lathe with a slotted cross slide that is easy to bolt work down to.

I don't tend to use the mill for boring cylinders unless the part can't be swung in the lathe as I don't find it as rigid and with no power feed in Z harder to keep a nice constant feed.

It's not the bore that is bad, That was good, it's the ends that are a tiny bit off, not quite perpendicular. Mounted in an expendible arbor between centers is my plan, that way I can touch up the ends and get them square. That's all I need. That's exactly what the cylinders are: A Stuart 10V, and a 10?H. What does the 10 stand for?

My little enco has mounting slots on the cross slide, but the enco is a piece of crap, jumps around and flexes too much. (and yes, I've taken out all the slack I could). The Grizz, disappointingly does NOT have the much loved mounting slots. I was considering making some "artificial" slots, that is, a plate that I could mount on the cross slide with some appropriate bolts and slots. What do you thimpfk? Is that a good idea?

 

[Jasonb]

It's just an engine number, same as the likes of PM Research use. The Stuarts tend to get smaller as the number goes up.

Engines with an A suffix are the more recent ones with A frame trunk guides, earlier ones had a single guide in the cast standard and a diagonal brace much like the current No1

This site gives a good description of all the engines that Stuarts have produced over the years.
http://stuartturnersteam.com/
As I said for a cylinder this size I would do it in the chuck so not really worth making a boring table, that's assuming you have a mill for doing other parts.