SHED MATTERS 2

[Stanley]

Not a lot to report this morning.... I was late in the shed because other things got in the way and then just as I was heading for the shed I had a sudden urge to clear a cupboard out, scrub the inside, wash all the contents and put them away again. I know it needed it but it's worrying! Could I be sickening for something?
However, I did get in the shed but have only done one small but essential task. I have scarfed the edges of the plates and the bed where the welds are going to be. I don't like grinding at any time and especially not in the shed but I was very careful where I directed the sparks and grinding dust. Nice to have that job out of the way!
No sign of the castings..... Fingers crossed!

[Stanley]

The lady from Hermes delivered at noon..... Well done Mick and John! You know what I will be doing tomorrow!

[Stanley]

Can't tell you how much I am looking forward to today. I love making working steam engine cylinders out of castings! If you get it right they are magic, the heart of the engine and it is all your own work.... They're good castings as well. John did right to persevere until he was satisfied.

[micktoon]

Sounds like you will enjoy today Stanley. Glad the castings arrived and seem up to scratch
Hope you have a good days machining.
Cheers Mick

[Stanley]

I'll leave you to judge, I was in there at 6AM and did five hours!



I started the day by tidying up in the shed, first thing was to bring all the parts into the kitchen to clear the decks.



Then I cleaned and oiled the big surface plate, put a clean tablecloth on and got my ducks in a row.



Before you start on the castings you have to get your head straight and understand exactly what it is you want to do. Castings by their very nature are rough, not square and you aren't even sure the bore is on centre, cores have been known to move during the process of casting. What we are after this morning is the most accurate face we can get for the valves to run on, that face has to be parallel with the eventual bore, the ends of the cylinders faced off square to each other and the cylinder bored in the centre of the meat of the casting. Mick had already driven some good hardwood plugs into the bores and my first move after a good inspection of the casting for surprises was to mark the centre of the bore as near as I can get it. Note this isn't the centre of the core hole, it's the centre of the meat of the castings. No easy way to do this, lots of intelligent guesswork! Once you have a notional centre marked on each end of both cylinders you are ready for the next stage.



First I mounted the big vise on the VM table and squared it with the ball bearing trick. Remember that what I want is for the surface of the valve face to be parallel to the centre of the bore so a bit of careful setting up. The ends of the cylinders are rough and not square at this point so you haven't got a perfect hold. Do the best you can and when you judge you are as close as you can get, tighten everything up and start cutting carefully.



Some time later you finish up with these. Don't worry too much about finish because the face will have to be milled again once you have perfectly parallel ends on the cylinder. You have to start somewhere and this will be your register until you achieve something better.



The Gospel according to Newton says that what you need now is a big 4 jaw chuck and grab hold of the casting best you can. The main things you are after is the valve face being 90degrees to the chuck face and the casting centre is the pop mark you have made in the wood plug. Take your time, get it as close as possible and then machine the face until you have a clean finish across it. I used my wobbler to get it as good as I could. Then start cutting across the face.



A quick check with the square and it is almost a perfect right angle with the valve face. Reverse the casting in the chuck seating the good face on the chuck face, centre it again and cut this second face dead parallel with the first. Later you can set the cylinder in the milling machine using these two parallel faces as your new register and take a skim across the face which will then be a perfect right angle with the the faces and dead parallel with the bore.



You'll never have the cylinder more accurately set up than it is now so you might as well bore it. You can see that the core was almost dead centre. I carried on boring long enough to satisfy myself that it will have got rid of the hard inclusions in the bore well before it reaches the finished size of 1.5". Then I knocked off. Five hours is too long for an old fart like me but I had got to where I wanted to be on the first cylinder..... Go and do likewise!

[micktoon]

Hi Stanley, well I would say this will go down as a good day You certainly seem to have got on well so far and all looking good.
Hope tomorrow is as good a day Stanley.
Cheers Mick

[Stanley]

You're right Mick, a good day. Lovely plugs made it easier. I went to the butcher's yesterday afternoon so I am almost clear this morning. Give some thought to coming down with the rest of the castings as once I have the cylinders in shape I need the other parts to carry on.....
Some initial tool sharpening this morning and on with the machining!

[Stanley]

I was a bit late in the shed but once in the task was to finish boring the first cylinder. So I got serious! Out with the 2" mike and the spring internal wotsits. (I've forgotten the right name for them....) Then I resharpened the milling cutter I used for the faces and re-installed it in the VM.



Every now and then we need to remind ourselves of certain things so I consulted Newton about the best tool shape. He's long gone of course but here's one of the cutters he used in the boring bar when re-boring full size cylinders. (There were three cutters in the bar). If a rounded point was good enough for him it'll do for me so I re-shaped the cutter in the boring bar and gave it a radius.



Good old Newton.... a big improvement from the sharper shape I was using before. I carried on boring measuring very carefully and on the last two cuts I didn't knock the feed off at the end of the cut but stopped the lathe, reversed the drive and came back though on a fine feed making a spring cut. The last cut was nine and a half thou....



and finished up with a nice bore half a thou above 1.5" which was the target. I checked at both ends and I have a half thou of taper but that's the lathe. It's a long time since I checked the levelling and adjusted the twist in the bed. Near enough for our purposes but I will keep it in mind.



Next job was to file the flash off the second casting.



And get it installed in the chuck as near straight and on centre as I could.



Knocking off time, I have the first end faced off at right angles to the valve face. This was the second attempt actually because when I got a face on it it was slightly out of square so a bit of thought and a good clout with the rubber hammer gave me as near perfect as I can expect. However, what I noticed was that the core isn't quite central in the casting so when I have reversed it and faced the other end I shall adjust the centre line. My pop marks are telling lies. Spotted it by the way it spun in the lathe. No problem while we are facing of course so I'll carry on using the centres but will have a readjustment before I start boring. At 1.5" bore I have less than 1/4" wall thickness so I have to be careful. But that's for tomorrow!

[micktoon]

More good work Stanley, looks like we will have to get cracking with the other bits as your not hanging about !!! When I did the wood plugs I was looking at the castings and had thought the cylinder wall thickness would not be too thick as it looks thicker wall than it actually is with the castings flaring out at each end. As you say just take it steady and measure carefully ......... I have every faith in you

Happy turning .
Cheers Mick

[Stanley]

You're right about getting your act together with the visit. Can't keep good women waiting and I need the other bits to finish sizing certain aspects of the cylinder.
You've always got to be careful about the walls, you want the biggest bore possible but enough meat left in the walls as possible.
Never trust cores, they have a mind of their own.....
As for having faith in me... that could be the kiss of death! Actually, I get better with practice and every engine I make is better than the last I think. Just how it ought to be...

[Stanley]

It took me a while to get the cylinder reversed and set up to my satisfaction so that this face was parallel with its mate but I got there in the end and faced it off. No need to worry about the overall length, it will be OK whatever it is as long as it accommodates the piston on a 2" stroke.



The faces are parallel, now I want to get the centre right....



I used one of the spacers I have for the rotary table and a transfer punch to get somewhere near the centre of the casting, not the core. It wasn't a long way out but enough to have got me into trouble.



I started with the boring bar I used yesterday but as soon as I could I swapped for this heavier bar as the eccentricity of the core was making life difficult. This cured the problem.



I'll admit to doing half an hour overtime, I was so near the target I decided to finish it. This is the last reverse spring cut that should leave me somewhere near.



Knocking off time. Both cylinders bored to within a thou of each other, a tad over 1.5". No need to be dead accurate because you'll be making the piston to fit. That's enough for this morning.....

[Stanley]

All over Britain men are slaving in sheds and some of them are working on the engines for Sarah and Debs.... Mick has been making the patterns for the castings of the personalised lids for the steam chests on the engines.....

[Stanley]

It was 9AM before I got in the shed, I had to write an obituary so it could go in the paper next week. First job was a good tidy up and for good measure I harvested John's non-ferocious off Mrs Harrison. I was going to leave it because one of the next jobs will be to make the pistons. But I have another little job in mind that needs the big 4 Jaw and is steel so it was easier to clean up than change chucks twice!



This is the little job that's been nattering me. Remember when I was practising welding I stuck a slug on the centre of this disc of steel which has been roughly flame cut and is about 8.5" diameter. If it's cleaned up it will become a useful piece of metal to have about but at the moment it's useless. The question was, could I get it in the chuck! The lathe is nominally 11" swing but remember that using the outside jaws this includes the jaws as well. I set the jaws as big as I could without fouling the ways and found that if I cleaned the edges up I could just get it in so I ground the periphery back a touch at each jaw position, that's the chalk marks you can see.



I hadn't made a bad job of centring the slug and it didn't take a lot of cleaning up. I can grab it with a 3 jaw now and have it reasonably true. It will come in handy eventually.



That's an improvement! Look how close the jaw is to the ways at 25 past!



It was getting near closing time so I had a good clean up and I'm ready for changing the chuck as soon as I want to do my next turning....

[Stanley]

We start this morning with a bleeding obvious tip. My favourite way of getting a chuck off is this bar and a big rubber hammer.



I decided to finish truing up the disc of scrap steel on the grounds that I don't like leaving jobs half finished and it takes a bit of pressure off my two little mates up in Geordie Land!



One pass across the face sorted that out. I had to go carefully on the periphery because of the after effects of the flame cutting. Some hard shops in it.



That looks a bit better, it isn't scrap any more. I oiled it up and put it in the treasure chest, it will come in useful for something eventually.



Another pressing little job. I noticed at one point when I was boring and hitting hard spots during the first couple of cuts that the far end of the saddle was lifting slightly. I've never adjusted it all the time I have owned the lathe. The light is shining on the sheet of paper to give me some reflected light. I nipped the gib until it was too tight and then slackened all the adjusting screws a touch and nipped the nuts up. The saddle is still free but must have a tighter grip now.



Back to the cylinders. First job was to mill a small flat on the opposite side of the casting from the valve face and parallel. This will make it easy to get the face square when I reverse the casting.



I turned the casting over and after a rough check with the spirit level to prove my setup I milled the valve face and the surface of the pad that will carry the exhaust pipe....



Then round the other side and on the same setting put a finish on the pads that will be where the drain cocks fit.



You might wonder why this pic. This lug on the back of the big vise is useless on this small mill and gets in the way by cutting down on the travel of the table. It has to go! I know it's sacrilege but doesn't alter the utility of the vise, in fact it will improve it. A job to bear in mind. Too big to go in Mrs McMaster, I will have to mill it off....



Knocking off time. Both cylinders at the same stage, a bit nearer!

[Stanley]

The Design Committee has been arguing all night as to the next stage and have not yet come to a recommendation....

[Stanley]

The design committee came up with three options, make the pistons, make a dummy lid and use it as a template for drilling the tapping holes in the cylinder ends or mill the the valve ports in the valve face. The one I fancied least was milling the ports so being a closet masochist I decided to do the last one.
I just about know the measurements by heart but started from the beginning, got my old drawings out and went into the drawing office. At the same time I blued the valve faces.



I marked both cylinders up, found the right cutters and set the first one up in the VM, cutting the steam ports first with the 3/16" cutter. Note the level for making sure I had the set up right and the sophisticated depth gauge (7/16") mounted on the cutter. Some black insulting tape actually.....



After cutting the first two steam ports I sharpened the 3/8" cutter for the central exhaust port before I used it and did the 3/16" cutter as well.



Some time later I had the first cylinder done and cracked on with the second.



At knocking off time I had done both sets of ports, cleaned the VM up and put my cutters away. If like me you overshoot your tramlines a bit at the side (look at the end of the exhaust port on the second cylinder), don't panic, the valve will cover this. The really important measurements are the edges of the steam ports because they govern steam admission and exhaust if you think about it. These are OK. Now then, another decision, what to do tomorrow?

[Stanley]

The sooner I get the big Abwood vise off the VM the better, I keep banging myself on it because it overhangs so much! So I decided to drill and tap the exhaust exit, 1/2" X 26tpi. As far as possible I use 26tpi brass thread for all the drillings into the cylinder. It make it easy to remember what thread you need to put on any fittings that have to screw into it like the exhaust and steam pipes. First do a bit of measuring to make sure I hit the bottom of the port but don't break into the bore! Than centre drill and away we go. You might notice that I have changed the ETM collet chuck for the big Belco 3/4" chuck. The main reason is that it makes it easier to do all the changes I am going to be doing with different sized bits, the secondary reason is that it's a good idea not to leave one chuck on the quill for too long as they can freeze on and give you problems.



The idea was to centre drill, drill 11.5mm which is the tapping size for 1/2"26tpi which suits a 3/8" bore copper pipe (the bigger the exhaust pipe the better!), tap the hole and Bob's your rich relation. Not so, I ran into problems! I'm not sure what the cause was but this bronze took the edge off my tapping drill, it's as hard as the hobs of hell! Almost like aluminium bronze... The drill you see here is tungsten tipped and it took this to get through in the finish and it squealed like a pig. Then it was hard to tap even with a sharp tap. But in the end I cracked it without doing any damage. (If you haven't got any expensive tungsten tipped drills sharpen a masonry drill carefully, it has a tungsten carbide insert and will do the job almost as well)



I often think that you can tell how much trouble I am in by how much kit gets deployed!



But eventually I had both exhaust passages correctly drilled and tapped with no mistakes....



I had an idea in my head that seeing as how I was taking the big vise off the VM table I'd mill that lug off the back but it's not going to be as easy as it looks so I kicked that idea into the long grass! I decided to get my angle vise set up on the mill and mark the cylinders ready for drilling the steam passages from the ports to the cylinders.



I had to take the jaws out of the vise to get enough room for the cylinder and then set it up using this long series drill for a marker. Then cut the seat for the hole with a 3/8" end mill, centre drill and use an ordinary jobber's drill to make the hole. It seems like a hell of way from the cylinder to the port and it's always a relief when you see chips dropping out of the port as the drill breaks through. (It drilled a lot easier than the exhaust passage!)



Knocking off time and the first of the four passages drilled successfully. The others will be faster because I'm set up now. Don't panic when you see how far into the bore the drill has broken. The seal on the piston is the ring or packing and this is nowhere near reaching that. Another thing, you'll find all sorts of esoteric advice about multiple drillings in some of the books. Ignore them and poke a 1/4" drill through, it's always worked for me. If the cylinder is bigger and you can get away with it, use the biggest drill you can. Steam ways need to be as easy as possible. Tomorrow is straight forward, drill the other three steam passages.

[micktoon]

Hi Stanley , quality work as per usual, funny how the port hole was so tought but as long as the other three exhaust holes go though easy no problems. I have got the valve chest pattern from John tonight so will alter the patterns as you wanted either tomorrow or on Friday. The weather has been really horrible here today so hoping for better tomorrow.
Cheers Mick

[Stanley]

Looking forward to the castings but don't get into a sweat! Take your time.... I can always find something to do....
I'm going to drill and tap for the oiler and the drain cocks once I have got the passages drilled so I looked the thread up for the cocks. 1/42 40TPI. That's the old Model Engineer's thread and a bit thin on the ground nowadays. What a good job I got myself a set when I was in funds. I decided at one point to get every set of taps and dies I could possibly need. They're all in that set of red drawers over the bench and I often wonder how much it would cost to get them all today. Somewhere well North of £1,000 I suspect, they get more expensive the smaller you get!
Trick question.... What do you do if you haven't got a 1/8" ME tap? Answer is go into the Whitworth section, a 1/8" Whitworth tap and die are 40tpi.
Quietly away we are making progress. (ME taps and dies range from 1/8" to 3/8" and were very popular between the wars....)
I keep looking at the bad shop on the side of the valve face on the two castings. They aren't going to affect the build but might give me some grief when I come to drill and tap for the studs for the chest and the lid. I shall just have to grin and bear it! They won't affect the looks of the engines because they are on the bottom side and will be hidden from view. That's why I haven't done anything so far about cleaning the sides of the valve face up. I'll make that decision when I get the lids.... I couldn't machine the rough shops out anyway, I suspect they will be quite deep.

[plaques]

"you should have heard it squeal.." You only have to 'rub' brass or bronze to give it a hardened surface that is very difficult to break through. Try removing this surface with a very sharp pointed tool. You must keep under the skin when drilling. You probably know all this but sometimes we miss the obvious.

[Stanley]

The drill was plenty sharp enough P, it was the material.



I started the day right by sharpening all the cutters I'm using, including the 3/8" slot drill to spot face the start of the passage.



Then I got stuck in again and drilled the three passages.



A while later and all four drilled.



I'm finished with the angle vice for now so a good clean it up and fit the normal vise, squaring it with the ball bearing on a stick.



Next job was to put a square finish on the bosses.



I popped the tap through the already threaded exhaust passages just to make sure they started OK after milling the face. The opening of the steam passages into the bore de-burred and we're ready for drilling and tapping for the drain cocks. Before starting I got the cocks out and checked that they were indeed 1/4" X 40tpi. All was well so over to the pillar drill and the compound vice.



Quietly away, centre drill, tapping drill and tap each hole, all on the same setting.



Close of play, all the holes drilled and tapped and I found time to tidy up and identify the leak on the air line that's been annoying me. Soon cured with some thread tape. Good morning's work, off for a walk and some veggie shopping....

[Stanley]

The Design Committee reminded me last night that there was one more drilling I could do......

[Stanley]

The drill and tap was the fitting of the lubricators to the cylinder.... So I knew exactly what I was doing....



I started by milling a small flat to accept the lubricator and then transferred to the pillar drill do drill and tap the holes. I spotted the first one and decided to have a last minute check.... What a bloody good job I did! I was putting the oil cups in the side of the cylinder rather than the top! So.... a quick reorientation and after several more checks (!!) off we went again.



I got it right this time and soon had them both drilled and tapped 1/4"26tpi.



That looks better!



I need to make the oilers now so I sammed up a piece of bronze bar from the treasure chest and got on with some plain turning....



By 10:00 I had got the blank bodies finished and fitted. What I need to do now is bore them out, thread them internally for the lids and make the lids. no rush, I am ready for a clean start tomorrow.

[Stanley]

The first job is to thread the inside of the oil cups. Straightening up in the chuck using the magic ball bearing.....



I used the spring loaded tap follower for the first time and it worked like a charm.



Both cups threaded, now for the lids....



I've never regretted the time I spent making my knurling tool. Perfect design and does a good job every time.



Not long afterwards, both lids made and fitted. Now we need two pistons....



A trip into the treasure box found this bronze bar. Then I put some tackle away. We are ready for tomorrow!

[Stanley]

Before I started I marked the castings so I can keep track. The pistons will be individually fitted.



The big Pratt 3 jaw is handy for this job, it takes a 1 3/4" piece of bronze in the bore. Away we go!



Getting serious now. Some careful measuring of bores, might as well make the pistons fit properly.



Little tip.... I needed to clean the inside of the bore up where the tappings have come through. A big split pin with a piece of coarse emery trapped in it does the job nicely....



The piston is bored 1/4" for the rod and the end counterbored to take not only the nut but the socket that will be used to tighten it up eventually. Then I cut the groove in the piston to take the packing and parted it off.



The piston for Debs cylinder finished and marked D.



The last thing was to set up for Sarah's piston tomorrow. I've been a bit slow this morning because In have been distracted by my back.... Hopefully there will be an improvement tomorrow!