SHED MATTERS 2

[Stanley]

The good news for me but bad for the shed is that I have just had a lovely long call from Janet..... I'm afraid that and cooking has buggered today's good intentions....

[Stanley]

The first job was to finish milling the faces and bosses. I am not trying to finish the whole casting, nowt wrong with cast finish in some places. Then I addressed the various holes that need to be drilled and the first job was some very careful measuring and pop-marking. Very slow careful work. These drawings were done by a model maker of the old school fifty years ago and at that time number drills were very popular. 'Luckily' I have a complete set so they came out of the drawer for the first time in yonks.



This was the smallest, a number 51, tapping size for 8BA. The other holes were a number 30 for the bosses and a 3/32" for the holes for the foundation bolts of the cylinder for some obscure reason. I didn't argue, I just followed the drawing!



Getting there....



Here's where I finished up. All the holes drilled except for one which I was warned by the drawing to leave until final assembly. The 9" Starrett clock calliper that Mick and John gave me came in handy again. Next job is some hand work to clean up the edges etc and make the bed look pretty. So I decided I'd done enough for one morning and knocked off.

[Stanley]

Busy day and I missed out on you yesterday Kids.... Sorry, I shall try to do better today!





I wanted to put a bit of finish on the bed, break the edges and generally make it look presentable. It's not my strong suite as you all know! I started by using an old trick of Johnny's for work holding when you want to file it. Simply pin it down on a board with panel pins.... Try it, it works a treat. As you can see a wide selection of files large and small were employed!



Here's where I finished up. Not perfect but looking respectable! Remember that a lot of it is bedding surfaces for other parts and the rest will eventually have a coat of paint I think. Now I can start thinking about the cylinder......

[Stanley]

I have been busy this morning and had less than an hour in the shed. I have to start looking at the cylinder now and it ain't easy! I thought I was reasonably good at understanding engineering drawings but certain aspects of these are baffling me. For instance one view appears to show the valve seat as being offset which it certainly isn't. The steam chest has two deep grooves down the side of it and they have me baffled. I'm going to have to have a long hard look at the plans before I do any cutting. There seem to me to be needless complications which are I think because the drawings are actually of the full size engine and some of the features like the grooves are unnecessary. We shall see but I can see me making my own before we are done!

[Stanley]

The design Committee met last night and the advice they have given me is to stop being intimidated by the drawings and to get on with making the bloody thing my way! I like that idea.....

[Stanley]

With that thought in mind I eventually got in the shed for an hour determined to stop fretting over the drawings. I was just going to make a cylinder.....



First thing was the mucky job of turning two wooden plugs up for the ends of the bores so I could find a centre.



Then I cleaned the VM, took the chuck off and replaced the collet chuck, clocked the vise in and tightened it and then had a good vacuum up because I had noted how much grinding dust there is about and in any case I wanted the shavings off the lathe. As is the nature of these things this led to having to empty Henry, the shop vac, he was getting full.



Here's the cylinder ready for operations....



And here's the mill all ready and waiting for the cylinder. It was 10:00 so I knocked off with a straight edge, ready for some serious milling tomorrow!

[Stanley]

There was nothing straight about the casting so the first job was to do some rough milling just to find surfaces, no measuring, all that can be adjusted later if necessary.



Then I put the four jaw on and grabbed the casting as best I could. All this is really rack of eye and judgement. Ideally this casting should be set up the old fashioned way on the saddle and bored with the cutter in the chuck but I haven't got tee slots so I have to do the best I can. Big does and little does I squared the cylinder ends, set the casting up as accurately as I could and then bored and reamed it.









The target was 7/8" bore and I finished up slightly bigger than that. But, it's almost dead central. Not the best bore I have ever cut but it's OK, as Johnny used to say, we aren't driving 300 looms! I shall review it tomorrow, if necessary I can still take a bit more out of it. Doesn't really matter of course as long as I have wall thickness because I'll make the piston to suit.....

[micktoon]

Hi Stanley, looks like you have made a good start and I think you have done the right thing going with your instincts and just doing what you think best. I am sure you will just work it all out as you go. At least you have plenty sharp milling cutters to keep you going
Cheers Mick

[Stanley]

Not 100% happy with it. I shall have a very close look this morning....

[Stanley]

I had another look at the bore and decided I couldn't live with it. So I had a bit of a think.....







I decided to make a mandrel to fit the bore as it is. Once I had that made I put the four jaw back on, Put the cylinder in the jaws and then clocked it in using the mandrel. The cylinder couldn't be a more awkward shape and it was a prolonged fiddle but in the end I got it within 10 thou of parallel and concentric. I decided that would do! One thing about the reamer is that to a certain extent it flexes and almost floats.



I finished up with a far better bore and finish. It's almost 1/32" over the 7/8" target but that's no problem. Now I have to clean up the outside of the casting where the jaws have marked it but that's no big problem. I am a lot happier now!

[Stanley]

As I have said before, this is a very difficult casting to hold and orientate. I have roughed the outside faces but wasn't satisfied with them so I used the orientation of the bore as a reference and set to to mill the rest of the faces using this as the starting point.



Once I had the valve seat correct I turned it over and did the feet. None of these were deep cuts, just remedial skimming because there isn't a lot of spare metal.



Once I had the feet square I tried the cylinder on the bed plate and after nailing it to a board again, filed the bed out until the cylinder fitted properly.



The last cut was something I have never done before. I milled the cylinder ends to make sure they were dead square with the bore.



At knocking off time I had the essential faces on the cylinder ready for final fitting. I think I'll have to have a think now as to how to proceed. One thing to mention is that I never received the lids, they will come later. I may make my own.....

[Stanley]

I was strong today and managed to ignore the comms for long enough to have over two hours in the shed. My first job was to make quite sure the feet of the cylinder are a good accurate fit on the bed. One of the best ways to achieve this is to simply rub the feet down on a good smooth flat file.



The next job is probably the most important and is exactly what I did when I was erecting the Whitelees. You spend a lot of time establishing a true centre line on the bed and the cylinder. If you get this wrong nothing will fit properly. Worth remembering that when you're making a small engine like this your tolerances are small as well. So, time spent on this is time well spent!



Once I had these two jobs done and got the cylinder clamped in exactly the right position I turned the bed upside down and poked the 3/32" drill through the feet from the back.



I hit a slight local difficulty with the drawings here. No matter how hard I searched I could find no details for the actual fastening of the feet to the bed other than a vague instruction to drill the feet Number 40drill. So in the end I ditched the drawing and made an executive decision! I decided to hold the cylinder down with four 1/8" Whitworth set screws. I sorted out my 1/8" tap, found a tap wrench small enough to hold it and tapped all four holes in the bed.



Once I was certain I had four good threaded holes I enlarged the holes in the feet for clearance. Being an old dog I gave them ample clearance for the set screws, matching four holes up like this can be a bit of a challenge.



I had to do a bit of overtime, these bolts are a fiddle but here we are with all four bolts fairly entered in the bed and the cylinder in line. I didn't tighten them down fully because I have to take them out so I can work on the cylinder. Enough to show that we have a fit. One interesting thing to note is the depth of the heads on these bolts. They are older than I am and date back to the days when nothing was skimped. Bolts with this depth of head must be just about unobtainable now, you'd be better off making your own! That was a good morning, slow and painstaking but a decent job and a good foundation for what is to come....

[Big Kev]

Good to see you getting your teeth into something, far more satisfying than repairing stoves I would imagine

[Stanley]

Both have their attractions Kev. Stoves are practical and less frustrating! Never mind, I am after all a volunteer, nobody forced me to do either of them!

[Stanley]

What a bit of luck that I had exactly the right tiny little spanner for the job..... I had decided that this morning was getting more finish on the cylinder, I'm satisfied with the surfaces in terms of size and orientation, I want to do some tedious finishing while I think about where to go next....







I won't bore you with long descriptions, I'll leave it to you to decide whether this was a waste of 90 minutes. I did my thinking and I shall attack the valves next.....

[Big Kev]

Looks very nice, you have far more patience than me.

[Stanley]

I wouldn't make that claim Kev. Horses for courses.... Mick has far more than either of us.....

[Stanley]

I managed an hour in the shed this morning and it was entirely taken up in marking the valve ports out and establishing their dimensions. No easy task, these drawings aren't laid out to be easy to read!



First job was to blue the valve face.



I made absolutely certain I was marking a true centre line. Then I checked my dimensions against the drawing.



This was where I finished up. I am certain I have the centre lines of the ports correct and I've found the correct sizes. I am ready for a set up and some careful cutting with very small end mills!

[Stanley]

Today's job was to cut the steam and exhaust ports. The sizes given in the drawings are 3/32" for the steam and 5/32" for the exhaust. Fine! The only problem was I haven't go those sizes to I struck a compromise and milled all three 1/8". Slightly bigger than specification for the steam ports and under for the exhaust. It will run at those settings.....



Set up and ready to go. Note the sophisticated thread depth gauge! It works fine.



It didn't take long to get there and I decided to drill the exhaust outlet and have a look at the flange that has to be made for the connection.



Outlet drilled and I looked at the specs for the flange that has to be attached to the cylinder. It calls for two 8BA countersunk head screws to fix it to the cylinder. A quick furtle in the treasures and I found two! Then I needed an 8BA tap.... I have them ready for tomorrow.....

[Stanley]

An encouraging start to a day of what I term 'watchmaking'. The cylinder covers have arrived. They were missing from the original order but Kirk has had some more cast.....

[Stanley]

Ready for some watchmaking! First thing was to sort out tapping and clearance drills for 8BA which is what we are working with here. The book you see on the bench is a very old one, 'Standard Screw Threads and Twist Drills' by George Gentry. I'll guess it dates back to the 1920s and it is very useful at the moment because the man who did these drawings in 1933 was one of the old school and uses Letter and Number drills. These are the series favoured in the small sizes by Mr Gentry so you can get some useful clues as to what was intended when you find a gap in the information on the drawing, and there are a few of them!



The first job was to find some bronze stock and make this 3/4" diameter flange which has to have two countersunk holes for the screws that fasten it to the cylinder and 4 studs for the mating half of the flange when we get to it. All 8BA. As you can see I marked the pitch circle for the studs in the lathe and scribed the cross divisions using the lathe tool also. The most accurate way of doing it.



The countersunk holes for the fixing screws first.



Then drill the stud holes tapping size, thread them and fit 8BA setscrews from the back because they are easily tightened up with a spanner when we're ready for that and any excess can be cut off. That was it for this morning, it's slow and fiddly work!

[Stanley]

The bad news Kids is that the shed has been cancelled for today. I need to write some articles for the paper.....

[micktoon]

Good morning Stanley, looks like you are making a lovely job and getting on well too, like you say watch making stuff going on, it's a good job you got your eyes sorted out or this would have been impossible.
Cheers Mick

[Stanley]

Mick. That thought occurred to me while I was making that flange..... I have another article I must write so the shed might take a back seat again today. Sorry kids!

[plaques]

the man who did these drawings in 1933 was one of the old school

He probably used First angle projection to lay out the views. This gets a little confusing when you have spent the last 50 years looking at Third angle projection. You can easily get disorientated.