Stuart 10V Build Log

[raynerd]

A good friend was willing to sell me this Stuart Engine 10V at a very good price and I`ve never worked on castings so this will be new to me!







I believe he purchased it with a machine or some equipment and has never touched it, however the original buyer sadly did!! An attempt has been made at machining the con rod and this is so off centre it will annoy me so I`ll need to make this again from bar stock.




Am I right in thinking that he has also drilled the lugs on the base box - I would imagine these would originally be supplied without holes ?? These are also not central but I`m guessing I`ll have to live with this




I have a few more nights work on one or two things in my workshop (primarly my final attempt at fixing my stirling before it goes on the top shelf (aka the bin) ... but then work should commence!

[John Rudd]

Chris, there's a build it guide series running at the moment in Model Engineer Harold Hall......

Building is best done with a few jigs and fixtures as featured in the mag...

[raynerd]

Hi John, yes I believe so. I must admit, I don`t get ME but I knew I was going to get this 10V a while ago so I managed to get hold of the articles 13th Aug and 27th Aug but apparently the new one is out and I need to get that asap. I`ve been struggling finding a copy.
It looks a nice little engine to build. I have read all that Harold Hall has wrote so far and I just wonder if some of the securing jigs/clamps are needed? - I`ve got quite a big 4 jaw chuck for my boxford and I`ve seen quite a few articles on the net just hold the castings directly in the chuck.

http://www.banjostring.co.uk/wordpress/wp-content/uploads/2009/12/DSC00716.jpg

Not trying to be lazy.... it just seems that he keeps explaining how the article is based for the begginer with no mill, I`m thinking some of the holding jigs are more for working and holding jobs on a small lathe. A few of the jigs are holding the boxbed and standard to the lathe backplate but I could hold it direct in the large 4 jaw or even face it on the mill ... infact would the mill be a better option?!

That said, I may follow his plans to the T so that I get it right!

Chris

[Jasonb]

You could do away with a lot of those gigs if you have a decent size lathe and mill.

And No the castings don't come drilled, as its just the holes for mounting to a base I'd be inclined to open them up with a slot drill in the right location and then either use an oversize fixing or glue in a sleeve.

Jason

[RichardShute]

I have a copy of the original 1950's Percival Marshall book by E T Westbury on building the 10V. PM me if it's of interest.

Richard

[raynerd]

Thanks Richard for your help!

I plucked up the courage to start machining some of my castings this evening. I seemed to have some sort of unfounded fear that I`d manage to chip or crack a casting some how, but strangely enough, it all went very well....infact, too well !

Despite reading all the books and the current ME article running at present on the 10V build, I chose to use my mill to true up the castings rather than mess around with jigs on the lathe. I`m not trying to be lazy but most of the books are aimed at lathe only workshops so I may as well utilise what I have. It was an excellent opportunity to use my X-axis controller power feed for the first time and I`m buzzing, it worked an absolute blinder! The finish is top notch and ten times better than what I was getting by hand and also the ease of use was great - find your left and right limits and just keep working between them taking cuts each time! It was luxury!!

Less woffle...here are some pictures, they are self explanatory:

Truing up the machine base and top.


I was impressed with the finish using my power feed!



Box bed top and bottom



Feet of the standard



Standard top which will seat the cylinder "before"!



,...and after



And all the bits piled in position!



Machining the holes/slots for the fly wheel bushes - I was wanting to use an end mill but didn`t have one of the right size so a drill bit did the job just as well. I took it through nice and slowly.


And how the bearing fits in position



Ok, nothing amazing....I best get reading, onto the more taxing jobs now!!

[Bernd]

Chris,

I'm amazed that when you milled the feet of the "standard" that it didn't come flying out of the vise.    Reason being, your holding that part by very little with the jaws. Next question will be how parallel will those two surfaces be, the feet and where the piston will be attached. It'll be interesting when you bore out the hole how square it will be with the casting and the crank.

Good luck.

Bernd

[raynerd]

Bernd, thanks for your input. I`m still learning! Could you offer any suggestions as to how I should have held it? I felt I had a good grip on it with my vice or I wouldn`t have attempted machinging, only doing light cuts, it wasn`t going anywhere. Much more secure than how I had it clamped down by the feet on the lathe.

I don`t see why there would be an issue with regards to the feet and top being parallel but I do think that when I bore the hole I`ll have to skim the top face as well so that the bore in the standard will be at 90deg to the face.

Advice appreciated..... I don`t post to show you how...I post for help and for people to pick up on these things so I can learn.

[John Rudd]

You might have been better securing the standard to a plate or block by bolting and then holding the block in the vice...

Chris what size is that facing cutter you are using please?

[raynerd]

John thanks for the suggestion although I think Bernd was talking about milling the feet; that the circular top of the standard wasn`t secure enough in the vice and I can understand where he was coming from. Although I thought it was secure and milling went OK, I did have concerns/thoughts about the issue at the time. Obviously I judged it was OK and went ahead. I wanted to mill the feet first so that this was the reference face and I could have used your idea of bolting this down, but without being faced I wouldn`t have liked to drill the holes in this for the cylinder so early on(and use these holes to bolt it down to a block).

Hummm, it is interesting.

How would most people go about boring the hole in the standard - I was going to use my mill but now pondering whether to mount on a faceplate on the mill!?!   OR perhaps use Johns idea and drill the bolt holes on the feet of the standard and mount it on a block and hold it in the lathe in a 4 jaw.

John, the cutter was a 3MT I think 2" (or 2 1/4") from RDG - http://www.rdgtools.co.uk/acatalog/copy_of_FACEMILLS__INDEXABLE__2_MORSE_TAPER.html

[raynerd]

...actually it has 4 tips so it must be the 2 1/4" but I`ll confirm when I get back to the workshop tonight.

[kwackers]

My tuppence.

Machining the standard is crucial to the engine working properly and not binding.

What you should do (IMO) is chuck a piece of bar that's as good a fit to the standard bore as is possible (given it's not machined). Turn down the end and cut a thread then bolt the standard to it, face off the feet so they're flat (oversize)

Bolt the standard to a faceplate by it's feet and centre up the bore. Bore it out to correct size and without removing it, face off the cylinder mount - this ensures the bore is absolutely at right angles to the cylinder face (crucial).
Next remove the standard and chuck a piece of bar turning it down until the standard bore is a good fit on it (a very slight taper - using a bit of emery will assist here) push the standard onto the bar cylinder end first and machine the feet to size. This ensures the feet are square to the bore.

You must get those steps right, otherwise your engine *will* bind.

[Bernd]

Chris,

kwackers has the procedure right. He was able to put into less words than I could.

Bernd

[sbwhart]

Chris,

kwackers has the procedure right. He was able to put into less words than I could.

Bernd

I agree.

You realy must get things square with these engines and the only reliable way to do this is by using the correct set ups. You have to think of a way to transfer the accuracy of your machine into the job once you understand this and learn some of the techniques the quality of your work improves greatly.

One tip with castings:- before you start cutting metal go over it with your digi vernier and try and work out what it will be like and what size it will be after you've machines it, the'rs bin many a job scrapped because the last operation has run out of metal.

Stew

[John Rudd]

Chris,

kwackers has the procedure right. He was able to put into less words than I could.

Bernd

the'rs bin many a job scrapped because the last operation has run out of metal.

Stew

Yayyyyy!!!!........Hands up those of us that have done that...

Great advice Stew...Definitely some to be be considered..

[NickG]

I will be watching this with interest Chris  , always fancied a go at a Stuart but always been put off by castings!

NIck

[raynerd]

Well thanks all for the replies and suggestions. I`ve tried to follow your advice and done the following this evening.

I did appreciate that when I bore the standard I would need to face up the top surface for the bore and cylinder mouning surface to be 90deg to each other so I have enough left on the length of the standard to work with it further.

So first up was using Kwackers advice of turning up a bar to fit well through the unmachined standard bore, thread the end (M10) and bolt up the standard. As you explined, this ensures the feet are square to the bore.

Sorry for the pictures, my camera battery has gone so they are taken on my phone!





Now the feet are machined, I made some clamps so that they can slot around the casting centre of each foot. This looks to be how it is done from looking at my pictures in the original book "How to Build a Model Steam Engine" machining a 10V. It seems to be nice and solid and secure.





So the next thing is going to be boring it out but it got late and I thought I`d leave it until tomorrow and see what you guys thought of my setup first...

Thanks again for the help so far.

[Stilldrillin]

Chris,
The last set ups are sooo much better than your first attempts.  

I've never machined a small engine from castings. But, as a long time machinist, your first pics scared me somewhat......  

David D

[raynerd]

Learning! 

Lol, that being said, shouldn`t have been such a dumb aŁ$3 to attempt !   Glad you think it looks better, I think I`ll try and bore this out today.
Chris

[NickG]

Chris,

I agree the last set-ups look better, but in my opinion, your first would have worked - as you say, the critical thing was the face square to the bore, so you would have had to bore it on the same setup in the mill. Out of interest, did you notice it taking an even cut when you did the feet and top face again in the lathe?

The only thing I have noticed is that you bored the hole for the bearings square to the bottom of the base rather than the top of the base that you skimmed, or did you skim the bottom too? I think it'll be ok, but i was just thinking, would it not have been best the way you first did it, i.e. both mating parts done in the same vice on the same machine - therefore if there was a slight angle built into it, you could flip one of the parts around and they'd be square again? Again, I guess the critical thing is that the bearing holes are square to that top face on the base now you know the standard is spot in.

Enjoying this, keep up the good work.    

Nick

[DMIOM]

......
Now the feet are machined, I made some clamps so that they can slot around the casting centre of each foot.  .......
So the next thing is going to be boring it out but it got late and I thought I`d leave it until tomorrow and see what you guys thought of my setup first...

Chris,

just an observation from a non-engine-builder - in your last photo:



It looks like the profiled (brass?) straps are bending - maybe something more robust could be useful?

Dave

[raynerd]

Thanks again for your comments....

Nick - I have to admit that when I did the feet again, it wasn`t a perfectly even cut at first so clearly although my original method cut the feet and top parallel, it didn`t cut the feet at 90deg to the bore. That being said, it was only a whisper out! My understanding is that now the feet are square to the bore, I bore and face the top surface and then use the same method for the feet again ensure the feet are parallel to the top cylinder mount surface. Just curious....if the cylinder mounting surface has been machined with the feet flat on the backplate - won`t the feet be parallel to the top surface anyway??

Regarding the bearing holes. I had skimmed the bottom first and then skimmed the top using the bottom as reference - I didn`t show this in my photos. I did think about this when I drilled for the bearings so I purposely mounted with the bottom face down...!? Since the bearings are screwed into position, there is apparently some movement in these anyway so I believe this isn`t too critical. Infact I think in the recent ME article, the writer explains that you can file the bearings holes by hand and do them slightly over size so that you can actually have some flexibility and adjustment in these.


Dave - the clamps are bending a little bit but they are a good thickness! - which suggests a little bit of heavy handedness perhaps. They are holding well and although I did consider making them out of steel (which I have) I choose brass so as not too over tighten and break the castings. Would others re-make these before going ahead and boring out?  Last thing I want is the Standard slipping. I do feel it is centred well and the clamps are really holding down on the feet.

Thanks again for your ideas.  

[kwackers]

Looks a lot better to me Chris!

Regards the bearings, you can file the profile out. The only important part of them is the mating surface that they bolt onto (the actual dip is purely cosmetic). The skim you did on the mill is spot on since the four surfaces will all be planar (the two bearing mounts and the two standard mounts).

Regards the brass hold-downs, I'd remake these in steel. They shouldn't bend!
The castings will take an immense amount of pressure - providing they're flat on the faceplate. With regards holding stuff in place you ideally should apply pressure evenly to the entire foot of the casting. What you've got is simply holding the corner, if you think about it this offers very little in terms of 'friction' and it would be fairly easy to break the edge off if the casting was pushed to the side.
So what you've got is ideal - but, remake it in steel, it should then be packed up at the other end the same height as the casting and there should be no bend when you tighten it up.

Other than that looking good!

[madjackghengis]

Chris, with regard to clamping iron castings one cannot clamp too hard, or too solid, iron having a very high compression strength.  You've got about half again the length of column away from the faceplate as width of hold down, so the side pressure as you bore will be multiplied by about one and a half, so you really want those feet down solid.  Steel is a definite, brass tends to have no spring in it at all, especially when it has already been taken past rebound, as the bending shows.  If there is any question about alignment once you've clamped it down solid, and bored and faced the column, take a piece of round stock in your chuck, turn it to a push fit on the bored out guide, and hold it in place much as you did to face off the feet the first time, and reface them, taking as little off as possible, and still get the whole of the feet surfaced, and everything will be square and accurate.  This particular part is the most critical of alignments for this form of engine and sets up all the other points of alignment, so getting this off a bit, will throw everything else off.  The good news is the setup is right, just the wrong material for the clamps, and cast iron when right, machines very nicely.  That is a very nice project to choose, and I'm looking forward to seeing the whole of the build, and eventually seeing it run. mad jack

[DMIOM]

and another tiny thing Chris - the repair-straps you've used for packing don't look to be anchored - my preference is that anything like that should have something other than just friction holding it in place - just imagine if that was spat out, with its relatively flat profile, when you were in front of it ....... (could be like some medieval weapon!)

Dave