Stuart 10V Build Log

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kwackers:
The way Nicks diagram above shows the facing of the steam chest face is fine.

What you're aiming for with the cylinder is the bottom to be faced at right angles to the cylinder, the cylinder bore to be parallel and the steam chest face to be parallel to the bore.

Obviously boring and facing the cylinder in one go will ensure the first. The second - just make sure your lathe isn't turning taper (some people use a boring bar between centres to ensure a parallel bore). For the steam chest the accuracy you'll get from bolting it to a face plate is more than enough (obviously check your face plate is at right angles to the bed and shim it to be so if it isn't).

As you surmise the top cap of the cylinder isn't important - although if it looks crooked you should sell your lathe - and mill - and any tools you may have. (You may keep one hammer though).

madjackghengis:
Hello Chris, Nick has made some very good points, as he says, steam engines are the most forgiving of model engines as they actually work above atmosperic pressure, and the first ones often had half an inch of clearance in the bore, and perhaps that much eccentricity and taper at times. I have recently just bored a cylinder for a tiny power steam engine, I used a four jaw chuck to get the bore as closely centered to the casting as possible, facing the end at the same time and then flipping it by loosening the jaw against the valve flat, and one other, putting the faced end flat against the chuck, which I know is accurate, but as you say, the second end needs to seal more than be perfectly square, so I concentrated on proper length and got that right, and it is in fact square with the bore.
I then took the cylinder and clamped a through bolt through an angle plate, the cylinder, and another angle plate, and bolted the angle plates to the table of my mill, then used a fairly accurate level to get the cast surface close to parallel to the table, and used a flycutter to face off the valve face. I used two angle plates because they were handy, and two offers much stronger support, far more against chatter than for any other purpose, not wanting the cylinder hanging out, however lacking a second angle plate, I would use an adjustable parallel, or carefully wedge the loose end of the cylinder with hardwood wedges, just enough pressure to ensure they stay in place, and not enough to tilt the cylinder up. I have used a file and dial calipers to measure the thickness of the cylinder wall to the face of the valve face on each end, and corrected a few thousandths difference with the file and finished the face with wet or dry sand paper laying on a surface plate, but the plate is not an absolute necessity, one can easily use something like an accurate angle plate as a standard to finishing, and for checking, or just a plain straight edge if you have one that is truly straight. The valve face must be pretty closely parallel to the cylinder bore, or the valve gear will tend to bind up, however a couple thousandths one way or the other can be compensated for, as long as it is flat, to ensure the valve seals well.
I use a set of magnifying lenses often a brand called "Optivisors", both for accuracy, and because my vision is not what it used to be, but they are useful for anyone doing accurate work, and I highly recomend them. Model engine builders fifty years ago, commonly finished the valve face with nothing but a file, and often took the cylinder to get it bored, lacking a lathe of their own, so it can be done quite well even with minimal tooling. For setting up your bolt circle to bolt the cylinder to the stanchion, you can plug the stanchion's bored hole with a plug machined for a tight fit, and with a "center pop" you can put a leg of dividers in, and scribe a hole circle on the top flange of the stanchion, if it takes six bolts to attach the cylinder, you can walk the dividers around, at the radius established for the circle, and careful stepping will give you an exact dividing into six, by the nature of Pi. If it calls for more, such as eight, one can walk the dividers around several times, incrementally adjusting smaller, until stepping all around puts the last leg back on the first mark. That flange can then be used to transfer the hole locations to the cylinder and also to the cylinder head, when it is machined. I think that should get you started on the cylinder, I am happy to be of assistance, I am not working on mine right now, because we are recovering from a flood over the past week, and my shop was running a foot deep, so it will be some time before I've got it cleaned up and working again, but I can sort of work by giving advise, and enjoying the work vicariously, if you find it helpful. I have a full and fairly complete machine shop, having retired from the business due to my health, but I started with a home made lathe, and hand tools, so I can adapt methods to what you have available to you, and if you do good work, carefully, you will have a very nice engine you will be quite happy to have built. I have Multiple Sclerosis, which limits my work to a couple hours a day, but does not interfere with my mind, and I am retired due to it, so what time I have, is mine and there is little effort in writing, so if I can assist, just ask, I enjoy seeing other's engines almost as much as seeing my own. Even the worst Chinese machine you can buy today is more accurate as a baseline, than the best of small lathes available for the hobbyist fifty years ago, so get well aquainted with all its warts and callouses, learn how they affect things, you will find ways around them, and eventually, an idea will pop into your head and you will remove a wart or two, and see a distinct improvement, leading to the next. I work on a 1948 Logan ten inch lathe mostly yet I have never stopped changing it, and improving it, even though it was a fine lathe when I bought it from e-bay close to twenty years ago, and rebuilt it fully. The main thing is getting to know your own equipment so you can immediately identify any issues that arise, and you will find it is absolutely true that the lathe can build its self, and is the only machine tool which can, and is necessary for the building of all others. I hope this is of some use to you, keep at it until you have all the parts of an engine laying around, and then you just put the parts together, simple, heh? :poke: mad jack

NickG:
Jack,

thanks for sharing those techniques there, I am sure myself and many others will find them useful. I have done the divider thing before as a kid creating pretty patterns with a pair of compasses but never thought to apply it to bolted flanges, that is brilliant for me as I don't have a rotary table or any method of indexing - I used to try to use the 3 jaws of the chuck to do it, I guess with some piece of metal that caused the chuck to stop in the same place on each jaw it would have worked but it never seemed to give me perfect results, I wouldn't be able to bolt it on in any position.

Sorry to hear about your flood and your condition, you do amazingly well. :thumbup:

Good point about the machinery of old and the fact that people did so much with just hand tools, I don't know how they did it, they were truely skilled men!

Nick

madjackghengis:
Hi Nick, thanks for the kind words, I appreciate them. We were not the worst hit with the flood, and I am truly grateful for that, my shop is not under water since yesterday, and doors are open with a wind blowing through, most of what I lost is the kind of scavenged equipment motors and the like one collects for future projects.
I learned the trade from reading, a year in high school, and from working by hand, gradually accumulating tools. For all who do this sort of work, "Lindsey Books" reprints the text books and the general books written as the ideas were conceived, by the great men of machines, precisely for the working machinist at the time when the trade was going from measuring in fractions of an inch, to measuring in thousandths, because steam engines need much less precision than do gas engines, so the books tend to give far more than any modern text book can for those who work with budgets and minimal equipment. I have six or seven feet of shelf of books just from Lindsey's, an they include books like "South Bend Lathes: How to run a lathe", and books by other lathe and tool manufacturers explaining in detail, all the many uses their equipment can be in an automotive shop, for instance, so I can't recomend the books highly enough. For those of you in England, all the books by Edgar T. Westbury, are top notch couldn't be better, and are more easily found there than here in the colonies. Knowing that "good mechanics" built model engines at home, in their spare time, without a lathe, and perhaps a drill press as their only power tool commonly, fifty years and more ago, has kept me from giving up on any difficulty, I have scrapped a lot of pieces in my learning curve.
Lots of machine shops did not have rotary tables until the second world war so the techniques they developed for accurate and repeatable work and recorded are exactly the things we need in our small shops, so any pre-war books will help a lot. The real test will be when Chris gets to the part of drilling the ports for the cylinder, and setting up the valve face of the cylinder. It's not hard, just requiring very careful layout and workmanship. I'm thinking I should perhaps do those things to my cylinder when he gets there, just to have pictures to show.
Sorry, Chris, don't mean to take over your thread. I hope you don't mind, and get your cylinder straight, true, and square, so we can get on with the rest, it really does feel good to "almost have a hand in it", and I might finish my steam engine before I finish my radial engine, which is in dire need of attention and has developed a bad attitude toward me. ttfn :poke: mad jack

raynerd:
MadJack - sad to hear about your equipment ruined by floods. We have had rain here, flooded areas but thankfully it has not come near the house. Your advice and comments are really useful and I do read all your replies!

I`ve spent two nights on this now - and things are going slow...but what is the rush I guess!! I was hoping to bolt everything down (drill and tap) and then get the cylinder machined. It has taken me 2 nights to make the jigs, drill and tap and also just face up the cylinder to tidy it up.

I hope I did this all OK but it has seemed to have worked! It is getting late so here are some pics for you but more questions tomorrow!

Jig bolted to the bottom of the standard for drilling the feet

Now on sole plate

...and on the boxbed

Holes drilled and tapped - here it all is assembled! Well the holes align at least :D Looks good imo!

Cylinder Casting before

I then measured the cylinder and found I have plenty of meat on it so took it to the mill to tidy the two faces up a bit. Then I read the 10V book and he suggests plugging the bore and marking out from the curved half of the cylinder outside to find the centre of the cylinder bore section. It does say in the book that you need to find the centre based on the outside as the datum, not finding the centre of the current hole in the casting.

Now my first question - I didn`t go any further than this but am I right in thinking I only need it roughly centred. So I`ve used a centre to align with my mark on the plug - is this good enough?

Well it is late...off to bed!!

Chris

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