Shed Matters 3

[Stanley]

I've used the drill jig twice this morning. In each case, a tangible improvement.



This fly cutter is here because I tripped over it yesterday and I'd forgotten I'd made it. It needs a good sharpening up.



This was the next proper engine matter. We need an exhaust port and a passage to the outside.





Some measuring and then under the mill. We have an exhaust port and a way out.





This one is a funny. It's the drilling of the bed to accept the Governor stand. I' m not planning on fitting a governor but as I have the bracket casting in the kit it seems like a good idea to fit it. So Two 5BA threaded holes in the bed ready for whatever.

[Stanley]

Here are the materials for this morning's target, to make the piston and its rod. A CI slug for the piston, some stainless bar for the piston rod and two CI piston rings. I discarded the latter and will use a soft packing to seal the piston. Favoured by almost all the loco makers and it will do for a miniature that will never have to run 300 looms....



First job was the easiest, make a piston rod, threaded 2BA for 3/8" at each end.





Then the piston, straightforward turning and just one groove for a soft packing seal.



Here's the piston and rod.



Here's where we are. Some major elements of the engine are starting to come together slowly. I'm not rushing....

[Stanley]

I started the morning by spending some time on the bed cleaning the casting and making it a bit more attractive.



Here's what it looked like a bit later, a lot better but it still has an untouched bottom surface..... I'll address that later.





First I put the bed under the drill and poked the 2BA clearance holes in.



Then I flattened its bottom....



Then I clamped the bed onto the base and marked the base with the drill. Then under the pillar drill for drilling and tapping.



Here we are with the 2BA connecting bolts fitted and you'll note I have had a funny turn and cut the piece of oak for the base. I might even get the router out later and mould the edges! A nice 2 hours and I am cheerful.

[Stanley]

Later, I did take advantage of it being dry and spent ten minutes putting the moulding on my plinth.

[Stanley]

The plinth fairy visited during the night.



I started the morning by doing another half hour on prettyfying the castings but this time using the Dremel.



Then a trip into the front room to mark 6 stud holes on the two lids. Dead accurate of course and Johnny was smiling over my shoulder.





Once divided, both lids under the pillar drill for drilling clearance for 4BA in ten holes but 5BA and countersunk in the two holes that are at the bottom of the front lid.



I had a tidy up and that's this mornings work done. More quiet progress.

[BobH]

I have been investigating the Vulcan gauge tester that you kindly gave me Stanley. It would be very useful to check gauges when carrying out steam tests on models. The connection on it is 1/2inch bsp male, so far so good, however it is a left hand thread. Before I look at making an adaptor does anyone on here happen to have anything with a 1/2inch bsp female thread that I could use?

[Stanley]

Sorry Bob no. There is a reason for that LH thread and I have forgotten what it is...

[plaques]

Left hand threads are used on gas bottles carrying flammable gasses. You could try a conversion nut to get a right hand thread.

[Stanley]

Now that's a useful suggestion! Full marks Ken....

[BobH]

Yes, making an adaptor is the solution. I just thought it worth asking first. This would have originally come with a set of adaptors in a nice box but have obviously long since parted company. On gas bottles left hand threads are used to ensure only the correct fittings are used but here, I suspect, it is so that when a gauge on test is unscrewed any adaptor does not come off.

[Stanley]

It'll be quicker than finding one and getting it Bob.

[Stanley]

So many ways to go but I decided that I needed to do the drilling and tapping on the cylinder. The first thing to do is to line up the cylinder and lids and mark them so that the relationship can be maintained. I have slipped up so many times with this that I am very careful.



After about half an hour I had everything sorted and marked.



Two of the holes in the cylinder have to be tapped 5BA for countersunk screws as studs can't be fitted due to the design of the bed. Nowt to it, I drilled with a No. 38 drill and tapped them and found I had gone wrong somewhere and I had stripped the threads out. (Nice one Stanley.....)



I then spent half an hour digging through the treasure chests for a solution, in this case through my collection of BA fastenings. I found two 2BA countersunk screws that will do and drilled and tapped for them, this time getting it right!



I drilled the lid for clearance and countersunk deep enough to get the heads of the screws below the surface of the Lid. Nobody will see these of course because they will be hidden in the joint between the cylinder and the bed. Here's the lid as it will be installed. Now for the rest of the holes which are all 4BA.
There is actually and advantage to this mistake. I can tighten the 2BA screws up far harder then the 4BA.... So more chance of a steam tight joint.



4BA isn't a thread I have used lately so I had to find a drill and tap and the 4 studs that make up the fastenings for the front lid. Not everything is marked clearly so you have to double check everything, that's why there is a 4BA nut there on the bench. It all takes time and so by the time I was sorted it was closing time. I shall come back to drilling and tapping fresh tomorrow morning. I don't want any more stripped holes!

[Stanley]

I'm continuing with the cylinder, more particularly it's fitting to the target face on the bed.



Once the studs were fitted I marked and drilled the bed and the rest of my time in the shed was spent making small adjustments, not only to the studs but the fitting of the gland in the bed, the register of the lid on the cylinder and lastly, the fit of the piston in the cylinder.



Here we are at knocking off time. Only one nut on the studs but we have a working fit. Slow but sure.....

[Stanley]

A small distraction this morning, I wanted a handle for a small file but couldn't find one. No problem, I made one. One of the joys of having a shed. (I vacuumed all the shavings up as soon as I had finished....)



I turned to the back lid and marked drilled and tapped for two studs so I can hold the lid to mark the other holes. A bit of fiddling, the register was fitted too close and had to be eased.



Ready to mark for the other holes....



That'll do. Move on to the steam chest.



A while later at knocking off time, I have the hole drilled for the exhaust and the housing for the Valve rod gland bored and ready for fitting. Note that both the cylinder and the steam chest are marked so I get the orientation right. A morning of quiet careful progress. Nice, I enjoyed that!

[Stanley]

A straightforward job this morning, drill the holes for the studs that hold the steam chest lid on and then use the lid to drill the cylinder and the chest itself. Dead easy, what could possibly go wrong?







Quite a lot actually if you get hypnotised by the process and quietly do accurate work and steady progress. What I did was forget to swap the clearance drill for the tapping drill so all the holes in my cylinder are too big! Deep joy!
It can be retrieved of course, upgrade the studs from 4BA to 2BA. I shall punish myself by making the studs but have also ordered some 2BA studding, it is never wasted and I am going to live forever!

[BobH]

That is the best way to think about it Stanley. I always say that the day I stop learning will be when they nail the lid on my coffin! Or do they screwthe lids on? I’ve never noticed screw heads on a coffin.

[Stanley]

Thanks Bob, all went well this morning until the gremlins decided to attack from another direction.... Read on....









You all know what I was doing and I was very lucky, at no point did the bigger clearance holes for the studs break out of the castings. Even better I realised I had 2BA bolts long enough to fasten the steam chest on by the time I have finished doing the final adjustments to the steam chest and lid.





I refinished the chest and lid, put them back on the cylinder and took the final cuts to tidy the joints up and this was where the gremlins stepped in. The lid had some chills in the corners and as I was finishing one skim cut the cutter grabbed on a hard shop and jammed in the cut. This broke the corner off the lid and jagged into the steam chest. Luckily the latter is on the bottom side of the chest and will not be noticeable.







No point pissing about, I need to make another lid. Remember the pieces of cast iron I have from the cistern I found in a scrap yard? I still have a few pieces left and found a piece that was near enough the right size. I gulleted my cutter and resharpened it and set about cutting. As you can see I have done the resizing and cleaned one side off. The other side has all the flaws in it and they will vanish as I mill it down to thickness. But that's the first job for tomorrow. Despite everything we have progress!

[Stanley]

I decided to reduce the lid in the chuck, you can hold a square object in a three jaw chuck as long as you are taking a facing cut. I'll get a better finish this way and I can do it on auto feed. I'm feeling lazy!





I cut it down to thickness with no dramas, marked it and drilled it.



Knocking off time. Ready for fitting. The stock was only just big enough but to good to reject. It's marked with witness marks and doesn't have any bits missing out of it!

[Stanley]

This morning I want to make 6 X 2BA studs for the steam chest. Before I do that I need to check that the holes in the new lid are in the right place. I can't guarantee my eyes are telling the truth.



As suspected, the holes need adjusting so I got the lid in the vice and adjusted the holes (made them bigger!) with a needle file.



As an aside, can anyone tell me what use fluteless HS 4BA taps are? I have often wondered and tripped over them again this morning.



I checked with 2BA set screws and the holes allow the lid to be fitted.



I need to make six 2BA studs for the steam chest and lid. Here I am set up in the lathe with clean 3/16" rod, the tailstock mounted die holder and my Trusty tin of Trefolex.



I tried the first stud I made to check I had it right....



Knocking off time, all the studs are fitted and now I can move on. Not a perfect fit but I shall do a bit of adjusting later to make it pretty.

[MickBrett]

As an aside, can anyone tell me what use fluteless HS 4BA taps are? I have often wondered and tripped over them again this morning.

Fluteless taps, sometimes called roll taps, don't cut the thread. They form it. They are supposed to create a stronger thread bacause they displace the metal rather than remove it. The drill size you use for them is different from cut taps (slightly larger).

You cannot hand tap with them as the cutting action is eccentric, they have to be used in a machine.

These kind of taps are used extensively in the aircraft manufacturing trade.

[Stanley]

Thanks for that Mick! I didn't know that.... they can sit in my BA box undisturbed.

[Stanley]

It's been a morning of small things, making the small brass parts that are the flanges for the steam and exhaust pipes and the gland for the valve rod. The flanges had to be drilled and tapped for 3/8" and 5/16" X 26tpi pipes. The gland is a straight turning. Even after knocking off they all need drilling for the holding down bolts and adjusting nuts. I've always said that you can't have too many chucks and once more the two jaw brass-finisher's chuck came out and saved the day.









As you can see, there was some very delicate turning! And here's what it looked like at closing time after 2 hours in the shed.



The parts are made, now they need fitting on the cylinder, but that's for another day.

[Stanley]

I have two flanges and one gland. I want to start fitting them to the cylinder and valve chest. The first move was to mark the PCD of the studs, these marks don't matter as they will vanish when I adjust the thickness of the webs.



I have drilled the holes and now I'm reducing the webs.



One thing that has to be done is break the cylinder and steam chest down so I can work on it. While I'm doing this I have eased the fit so that the steam chest and lid fit together easily.



This was where I had got to at knocking off time. I have the flange for the exhaust fitted. I haven't tightened it down completely because it has to come off again. One problem I have hit is that the 5BA studs included in the kit are slightly over size and very difficult to fit into holes tapped with my almost new Presto 5BA HSS taps which I am sure are accurate. No point moaning, just carry on working at the fitting. You'll see I have the flange and gland ready for fitting and have found two of the four studs I need. I shall make the other two.
Slow and complicated but no mistakes and quiet solid progress. That'll do me!

[Stanley]

One point before I post today's work. I said I was sure that the new Presto taps were accurate. I might have been wrong because I tried another 5BA tap and the studs fit. This might of course mean that the tap is cutting oversize.



Here's the start of today's jobs which is to fit the valve rod gland and the steam pipe flange. Drill for tapping the stud holes for the gland.



The gland is fitted and the valve rod slides freely. On to the Steam inlet flange.



I've drilled and tapped and fitted the flange using two larger studs (The correct ones are missing.) Not a perfect job because the right hand stud has hit the bolt hole in the steam chest. I shall have to be imaginative when fitting it, it will be all right but not perfect!



Next I had to cut the over size studs and thread them, no easy task when they are that short! This is where I knocked off. Ready for making the steam and exhaust pipes and then addressing the valve. The casting is laid on the drawing, Number 31 on the sheet.... But that's for tomorrow.

[Stanley]

I returned to the bad stud in the steam pipe flange and spent twenty minutes getting it straightened up. It's better now but when I get round to fitting it I shall make two new studs. The main thing is it is straight.



This is the focus for the rest of the morning, the steam valve. My first move was to clean the flash off it and get it ready for measuring, marking and milling.



I started on the milling but decided my cutter wasn't sharp enough.



So into the T&C grinder and back off and resharpen.



I won't bore you with more pics. This was finishing time, the cutter is much better. I still have more cutting to do on the valve but that is for tomorrow....