SHED MATTERS 2

[Stanley]

Today we're looking for two bearing brasses for the crank pins. So the first job is to set the crosshead, put the crank pin on the correct centre and get some measurements.



I have this slab of brass which will just about do it if I'm careful. It's not as good as it seems, the other side is scabby from casting.



For the first cut the slab was big enough to go into Mrs McMaster.



The reduced piece needs to be split down the centre so into the HM.



Just as I was finishing that cut the saw broke. Usually it's because I have done something wrong but this time you can see it's an old crack that has decided to let go.



Box on, we have two pieces somewhere near the right size.



Into the mill and start looking for accurate square blanks....



Milling the scab off soon takes the edge off the cutter so a trip into the T&C grinder.



Once I had two sides and two edges cleaned up I squared one end ready for cutting off to length.



After another measure and mark and a trip into the HM again with a new saw blade mounted, we have two square blanks. All we have to do now is make them into bearings!

[micktoon]

Hi Stanley, you are not having much luck with them saw blades in the HM, at least this time you do not have to kick yourself for doing something wrong, just a shame another one bites the dust. I have been keeping an eye open but not seen any yet but as I am typing might just have thought of someone that might have some maybe so fingers crossed. Another thing its brought to mind is someone was using a tungsten tipped circular saw blade on a forum I am sure, the reason being they were much cheaper, maybe he was only cutting ali ?
The engines are certainly looking like engines now Stanley, you will have been on double time again today with it being bank holiday too

Cheers Mick

[Stanley]

Yes Mick, but this one was evidently on its last legs, it was cracked almost half way through and has evidently been like that for a long while.
Yes, they're coming along nicely... Quietly away, no rush!

[Stanley]

First job was to clean Mrs Harrison and take the 3 jaw SC off, I want the 2 jaw and a clean lathe so I can harvest John's non-ferocious.



Then I put both the blanks under the mill and took a light skim off all the edges to make sure they were dead square.



Both blanks marked and punched and ready for drilling centres for the bearing and on the end as an aid to getting the bearing square with the con rod when I fit it.



I soon had the centres drilled....



I sharpened a 19mm drill and relieved the cutting edges. Popped a 1/4" drill through and then enlarged the hole to just below the finished bore.



Both blanks bored and marked for the stud holes.



Then some accurate setting up and bore the stud holes out 3/16" which is clearance for 2BA.



Both blanks bored, marked for the saw cut, edges broken and ready for their studs.



Knocking off time. I've changed the two jaw for the 3 jaw SC, got the 2BA die out and found the stock. I'm ready for stud making tomorrow.....

[David Whipp]

You've made good progress in the few days I've not been on here Stanley. Fascinating to see machined parts magicked out of lumps of metal! (If that's not some sort of heresy...)

[Stanley]

Isn't it David. That always strikes me as well. I've often said that the fascination of playing in the shed is that you can alter the shape of lumps of metal you couldn't mark with your teeth! I reckon it's a form of sculpture. I especially like it when you start with a scabby piece of brass like this was or a lump of rusty scrap... Definitely magic! That reminds me David.... FYM??

[Stanley]

I was slow getting in the shed this morning but have done good work.... The first job was to split the two bearings. I put a new blade in the Junior hacksaw (No pockets in a shroud!) and used a straight edge to guide me. I didn't get the cuts quite straight but it doesn't matter as they are mating surfaces.



The two bearings split and witness marks stamped on them to ensure a match.



Then a bit of stud-making after a careful measure up!



Studded up and tightened, we're ready for boring now.



The journals are slightly different sizes so some careful measuring and the brasses marked for Debs and Sarah.



It was coming up to knocking off time. I changed the chuck for the two jaw, mounted a bearing in the chuck centred by using the tailstock centre. The pilot hole is no longer circular because of the saw cuts but this will still find the centre. I dressed the grinding wheel, sharpened the boring bar and honed it and set it in the toolpost on centre. Ready for boring tomorrow....

[Stanley]

I left everything set up yesterday so this morning I got serious, broke out the micrometer, did some serious measuring and bored the two brasses. I aimed to give them 2 thou clearance on the journals and got very close to target....



Here's my cunning wheeze in operation. In the past I've struggled to get the stud holes marked accurately in the foot of the con rod. I decided to try a different way. Remember I cut a centre in the end of the brass? I found a bit of threaded rod that was an exact fit....



I chocked the crosshead and after getting the brass centred on the con rod foot with the peg, put a bit of pressure on with the crank pin and marked both stud holes with a transfer punch. Dead easy and guaranteed to be on centre and oriented correctly. Then I put a good pop mark on the transfer punch marks.



And after checking carefully I had the foot dead square, drilled the pop marks 3/16", the clearance for the 2BA studs.



Lovely result, very close fit, I just had to ease one hole slightly with a small round file. The studs are tightened up dead tight.



The next job was to release the crossheads from the piston rod and drill an oil hole in each of them with a small centre drill. Don't ask me why or how but I got Debs a bit off centre, sorry about that!



Then into the VM and I started by milling the ends of the feet so that on the heavier cut I could grab the con rod as well as the brass. This was a bit precarious as I only had hold of the brass so some careful light cuts.



Not long afterwards, both cut on the ends.



Then, back into the mill and cut the long sides.



By knocking off time I had Sarah's finished. Things were going so well I felt like crashing on but took a firm grip of myself! The nice thing is that the cuts talk to you and soon let you know how accurate you have been up to now. The cuts coincided well, I have been keeping things very close to perfectly square.... Nice!

[Stanley]

Not so nice actually and a good illustration of how easy it is to slip up. If you look at that last image I have attached the brass on the assembly I milled the wrong way round! The centre in the end should have alerted me. I noticed it last night when I cast a loving eye over progress, reversed it and found that there was a slight discrepancy in the junction of the rod with the brass. Easily put right, I shall give it a light skim this morning but it could have been much worse! It just goes to show, you have to think carefully and check twice! Even then you might miss something and it can be very dispiriting when you find you have ruined something that has hours of work in it. This game keeps you on your toes!

[Stanley]

The first thing I did this morning was to put the con rod that I did yesterday back in and take a light skim off it. It turned out more square than yesterday because the brasses are the right way round. Then I cut the other one down and what you see here is both of them milled.



After a chip chase and clean up I swapped the 2 jaw for the 3 jaw SC chuck, mounted my linishing plate and spent a while putting some finish on the assembled rods and brasses. I didn't aim for perfection, why break the rule of a lifetime! But I did enough to make them look pretty. Well pleased with them, tomorrow I can get on with mounting them once I have drilled oil-ways in them.

[Stanley]

First job was to poke a 3/32" hole down each side of the connecting stud so that you can get oil into the crank bearing.



Then connect the con rod to the crosshead, drive the taper pin home but don't cut it off just yet in case it has to come off again. Take the cap off the bearing and pop a bit of coarse grinding paste into the bearing and on the crank pin before tightening the cap down. Put a driving dog on the shaft and turn the bearing until the bearing settles in. Take the bearing to pieces and clean the paste out. You'll now have a nicely frosted surface in the bearing. Clean the surfaces, oil and reassemble with the cap bolted down tight. If you've got everything right you now have a close to perfect fit on the journal.



Take the back cover off, screw the piston rod out of the crosshead and withdraw the piston on its rod. Turn the flyshaft a bit with the dog and make sure you have a nice fit.



We're into packings now so a dig in the treasure chests for graphited asbestos string and a Jubilee clip that fits over the piston.



Split the string into smaller strands and wind them tightly into the groove on the piston until they stand proud of the surface then compress the packing with the jubilee clip. Get as much in as you can.



Slacken the clip a touch and then drive the piston into the bore using a piece of wood to avoid marking it. It will feel much too tight but if it moves at all it's OK. Drive it right in until the clip drops off. You'll find that the edge of the bore has cut the excess packing off. Get rid of that.



Engage the end of the piston rod with the crosshead and tighten it down dead tight using the socket on the 1/4" nut recessed in the back of the piston. Put some liqid gasket on the back cover and bolt it down tight.



Then address the gland nut packing. Pack single threads in and compress with the gland nut. Keep doing this until you feel you have enough in there. Tighten the gland nut down.



Try the rotation before removing the driving dog. We're looking at an almost completed engine! All it needs is the valve and rod. But that's enough for today. I'll repeat all this on the other engine tomorrow. Once that's done, we can start thinking about valves!

[Stanley]

First job was to move Sarah's engine onto the sideboard to give me a bit of room. I think it looks all right!



Then away we go with debs engine, exactly the same as yesterday. No surprises and after a bit of careful work it was laced up and ready for valve making.



It had got near knocking off time so rather than plunging straight into valve making I had a good clean up and put all the tackle away. That included restoring the treasure chest corner back to normality. Small sheds are all right but they make you keep things tidy!



I finished off by vacuuming. I work better if things are clean and tidy so that included Mrs Harrison as well. Nice straight edge and I can get straight into valve making tomorrow. We are on the last lap!

[Stanley]

It's a very satisfying stage where I can see all the hours of work coming together. I shan't be rushing this morning now I am on the home straight. If anything I shall slow down.... I can see an easy day coming up. This is where you have to get things exactly right, the valve is the heart of the engine.....

[Stanley]

As forecast I copped out this morning. I opened the valve chest up on Debs engine and took my particulars. I also checked the throw of the eccentric.



This was knocking off time. I have all my fag packet drawings done and I've been lucky enough to find two pieces of bronze in the treasure chest that I can get two valves out of. Didn't feel like staring milling so I came out of a tidy clean shed leaving things ready to start in the morning. An easy day will be good for me.....

[Big Kev]

Anyone comfortable welding cast iron?

[Magnu420]

Anyone comfortable welding cast iron?

a guy at gissing lonsdale did a bit of cast welding for me
paul his name i think

[plaques]

I've had a number of jobs done at a small outfit in Nelson. Mainly motorcycle cylinder repairs, broken fins, exhausts etc. The success of getting a good weld is a combination of the competence of the welder, good equipment and the quality of the cast iron which you are starting with. If its just old fire grate stuff forget it. It probably won't be worth the trouble.

[Stanley]

I have some CI rods Kev and have got away with it in the past. Nickel based and a machinable deposit. If you bring it round and let me have a look I can tell you whether I think I could do it. I'm not the best man in the world but as I say, I've had some success.

[Big Kev]

Excellent, thank you. It's the top plate of my morso stove. It is removable but I may bring g it round in one bit, it may distort otherwise and I wouldn't get it back on. It won't e until the weekend as I'm early shift this week. Is that OK?

[Stanley]

Yup. No promises mind you but bring it round and let's have a look at the rabbit.....

[Big Kev]

It doesn't have to be pretty

[Stanley]

We'll aim for effective and pretty!



Today was dead simple, make two usable blanks out of the bronze I had. Neither of them is perfect, all Im looking for at the moment is six faces at right angles and as near to 13/16" thick as I can get.



There were some hard inclusions and they soon knocked the edge off the cutter. God knows what I would do without the T&C grinder....



Knocking off time. Two hours in a very warm shed and we have two useful blocks. The larger one has a very nasty inclusion in the corner but we can lose that when we measure and mark tomorrow....Worth noting that both these pieces are cast bronze, the best material for the job!

[Stanley]

I'm looking after myself in the run up to teaching at Keele so I wasn't in the shed until 8AM. I indulged myself by having a play with my height gauge and Matrix slips.... If you remember I had a problem working out how to get my measurements correct last time I had it out. I cracked it this morning and used it to mark out the blanks I have for the valves.



I managed to mark the cuts avoiding the worst of the blow holes etc.



Then into the HM to cut the meat off before milling to size....



Cut to approximate size and would you believe it I forgot the bad inclusion that was blunting the cutter and managed to include it in the blank!



However, I had allowed about 1/8" for milling and managed to get rid of the problem while milling to size. Knocking off time, ready for some more shaping!

[Big Kev]

Yup. No promises mind you but bring it round and let's have a look at the rabbit.....

Are you about Friday afternoon (outside of nap time)? If I bring the stove round is there somewhere I can put it for you to look at, at your leisure? I don't want you having to move it around as it's a bit of a lump.

When would be best for you?

[Stanley]

15:00 in the back yard Kev. No good if it's raining.... Bring your clear goggles round, you will be doing the grinding!



In the shed at 8AM. First job was housekeeping, this cutter needed a complete regrind, backing off as well as sharpening.



The job today is to cut the slot for the valve rod and the transverse slot for the driving bar. So a bit of measuring and marking.



I could have cut these slots on the VM but the HM will make a better job and of course I have the advantage of the power feed on the table which saves wear and tear on my shoulder! I got set up with both valves ganged in the vice and took a light cut with a 1/4" cutter. Then I did what I should have done first, checked the diameter of the valve rod. You've guessed it, it should have been 3/16"! So a change of cutter and quietly away....



Once I had the slot for the rod machined, a bit more marking out, a change to a 1/2" cutter and I milled the slot for the driver bar. I did these one at a time as it is a heavier cut and to tell you the truth this cutter needs sharpening.....



Knocking off time, one valve finished under the HM the other is ready for tomorrow. Once more I reflect on the fact that all I do is chew lumps out of pieces of metal and make them smaller.....
A bit of bleeding obvious here for anyone who is following this valve-making job for the first time. Forget the usual complicated ways of making the slide valve and go for Newton's way which is what I do and it always works. The piece you are looking at will eventually be the valve. The narrow slot is for the valve rod and the wider transverse slot is for the driving bar through which the valve rod is threaded. The valve itself is free floating, steam pressure will force it onto the valve face. The slot is slightly deeper than necessary so that if you should get a slug of water in the cylinder it can lift off its seat and discharge through the exhaust. The driving bar is a good fit but free to move. The valve rod will be threaded 26tpi so half a turn of the valve rod from outside the chest will adjust the valve 1/52", so you can do fine adjustments without taking the valve cover off. There is no locknut on the valve rod, it doesn't need one because it can't rotate while connected to the external rod from the eccentric. It will all become clear as we build it and I recommend the method to you. It has never let me down.....