Final stages of “Jinty”

[don9f]

Hi, new elements silver soldered into the headers, all cleaned up and checked, joint & ‘o’ ring in place, so these are ready to fit to the boiler:-





However before that, the main steam inlet to the cylinder block needed fitting. The drawings show no detail of how the smokebox is to be sealed around the exhaust and steam inlet and the way I’ve done it means the steam pipe can’t be screwed into place until after the boiler goes on, however this is easy to do.

To seal around these two pipes, I made some “infill plates” that match the curve of the smokebox and are a close fit around the two pipes. They each simply fasten with a single screw and on assembly, I smeared some high temp. silicone under them and around the base of the pipes:-







Once this was done the new superheaters were fitted, the pipe to the snifter fitted (very fiddly) and finally for today, the blast pipe cap.

Next job is to try and fit the pipe to the blower, but I’ll probably have to make a special spanner to tighten the end that goes to the hollow stay....it’s getting a bit crowded in there now!



Then it’s on to the petticoat & chimney....

Cheers Don

[delaplume]

Nice one Don-----Exactly as in some full size.....My experiences were of GWR and LMS locos and I think BR Standards as well ??--------They are known as Waste plates and are meant to be changed on a regular basis as and when they deteriorate...

[mbrown]

I have found that the best tool for tightening the blower union on the end of the stay is a home made spanner with the jaws at right angles to the handle, the latter made long enough to be clear of the smokebox, and with another right angle bend to allow you to apply some torque - if that makes sense.

Malcolm

[don9f]

Hi Malcolm, yes it does....that’s the sort of spanner I’m going to make.

Thanks Don

[JonL]

That looks almost identical to my William layout. At the expense of realism I get a split smokebox... might make things a bit easier with my big fingers...

[don9f]

Hi, yes it’s pretty much standard Martin Evans, the internal dia. of this smokebox is just under 5 inch, so not too easy to work in....at least it’s only short though!

Cheers Don

[don9f]

I had some unused combination spanners that I picked up from Model Engineers Laser at one of the shows and filed the jaws of one of them out a bit to fit 3/8” a/f nuts....these particular ones are laser cut from 3mm thick 316 stainless. The jaw part was then bent over at 90 degrees and this tool was used to tighten the blower pipe union nut onto the hollow stay fitting, no problem:-



The chimney was almost ready to be painted but I decided that the skirt needed a little more work to thin the flange edge down and to remove some casting marks that were still visible. More filing, drum sanding etc. but I’m not aiming for any sort of immaculate finish....the real ones sometimes look a bit rough!

Along with the smokebox door and the dome cover, the chimney will emerge painted in the newly acquired Satin Black from a Motor Factors in Derby that I was recommended to use. I’m going to leave the boiler etc. for now in it’s Halfords Satin Black and repaint it later on when the weather has warmed up a bit.

As I’m now looking to carry out a steam test next week, I sealed all the various fittings that are screwed into the manifold, checked any gland packings etc. and mounted it properly via its flange on top of the firebox. Stainless studs and nuts have been made and coated in copper slip during assembly. Same goes for all the pipe union nuts & cones which are now “finally” assembled. A new joint was made for the regulator bush and the regulator rod and its gland nut packed with five turns of graphited yarn. If I was making this fitting again, I would redesign it to use an ‘o’ ring but the packing should work well. The seven studs and nuts that hold the regulator bush in place are stainless and again, copper slip used to aid future disassembly:-



The water gauge fittings are very “chunky” and I don’t really like them, but at the end of the day this is not a scale cab by any means and at least they match the other chunky manifold valves! I made a new bottom nut that incorporated a shroud to give a bit more coverage of the firebox crown when the water is “in the bottom nut”:-



The three (commercial) clacks came with 3/16” stainless balls and I've replaced those with 7/32” nitrile balls. The one near the cab floor is for the handpump, the two for the injectors are near the front tubeplate....non scale positions for the majority of 3Fs but the preserved 47298 has bosses blanked off in those positions and it looks like that for some reason, engines fitted with condensing apparatus had their clacks like that.....anyone have more info for interest?

Next will be fitting the blowdown valve and making something that can make use of the discharge pipe for backfilling the boiler. I’ve got two safety valves but they are both what I call the “Farting type” and make that loud irritating noise when blowing off. I have the drawings and springs to make some Gordon Smith types but will have to get some bronze rod to do that.

Cheers for now Don

[Deleted]

I've bought a few of those spanner sets from Malcolm...they are excellent for tight spacers...would also with a little modification make good scale spanners for the loco toolbox...

[steamer5]

Hi Don,
Looking good, hope the steam test goes well.
On the nitrile ball front my experience with them is they are great for a while & then you start having issues that come & go. By shear chance I discovered that in use they change shape! I used like for like size & I see you have gone up a size so may not be such an issue, it will be interesting to find out how you get on over time. I’m going to change mine out for nitride ones, just got to get my act together!


Cheers Kerrin

[don9f]

Hi I mentioned recently about making new safety valves, as the commercial ones I had made too much noise (I had tested them under steam a while ago).
Not only that but the threads at the base, wasn’t very concentric / true with the centreline of the body on either of them, this being visibly evident when they were side by side, screwed into their bushes....so they had to go !

I had located the correct springs for the Gordon Smith type in my workshop, but despite a thorough search of there and the entire house, could I find the drawing, which I know I had bought at the same time as the springs? Of course I couldn’t !

From measurements scaled from various photos, the GS type for the Jinty are obviously based on his “SV#2” design, so as a drawing of this type was available online, it enabled me to carry on without having to re-order a drawing, making my own alterations to the SV#2 to suit. Only the upper part of the real ones are normally visible, so it doesn’t really matter what the lower part looks like:-



Anyone familiar with the Gordon Smith designs will know that one of the crucial dimensions is the amount the ball protrudes beyond the shroud of the guide rod part. I have noted references elsewhere on this forum to possible errors in achieving the correct distance from the bottom of the shroud to the top of the valve seat....no doubt being influenced by the precise diameter and shape of the edge of the seat. Anyway for now, I’ve made them to the drawing and hope to test them under steam soon:-





At this stage, the brass adjusting piece and the guide rod are a bit over length....I’ll trim them once I’ve set them to 90psi, so they’ll look a bit scale-like:-





Hoping to do a preliminary 1.5 times hydraulic test tomorrow prior to steaming it if things go to plan!

Cheers for now Don

[steamer5]

Hi Don,
Have sent you a PM. Can I just ask, what type of ball are you using? It looks to be ceramic, or is it a trick of the light & stainless?

Cheers Kerrin

[don9f]

Yes, I was going to mention that but forgot....I’ve used 3/16” Silicon Nitride balls in these particular valves.

Cheers Don

[steamer5]

Hi Don,
Thankyou, now did you press them, as per Roger, to form the seat or just leave the seat as machined?

Cheers Kerrin

[don9f]

I’ve never had much success with giving the ball “a light tap”, as you sometimes hear, but find gently squeezing the ball onto its seat works well for me.

Having put water in the boiler yesterday with the clacks newly fitted for the first time, one of the two at the front leaked back through the injector with a steady drip (they are below the waterline). I took the cap off to make sure it was clean etc. (remember this is with a nitrile ball), reassembled it but it still leaked !

Today I took this commercial clack off and looked at the seat under a magnifying lamp and could see that it was poorly finished....ie chatter marks etc. I set it up in the lathe and carefully re-cut the seat, checked the hole with a 5/32” reamer but this was a loose fit, so I don’t know what size it was made with. Anyway I know at this point the seat had a nice square edge, squeezed a silicon nitride ball onto it, rechecked under the magnifier and could see a nice tiny chamfer on the seat edge. Replaced the nitrile ball, reassembled and now....no drip !

Cheers Don

[don9f]

Hi, having mentioned a few days ago about carrying out a 1.5 x working pressure hydraulic test, then steam test, I thought I'd write a bit of an update on that, as things didn't quite go to plan....

Firstly the regulator leaked such that hydraulic pressure couldn't really be raised at all. When I "finally" assembled the regulator valve, its stand and the main steam pipe etc. recently....like many parts, these had been made a good few years ago....everything seemed ok, but obviously it wasn't!

I removed the superheaters etc. and blanked off the main steam pipe where it emerges into the tubeplate header bush and was then able to successfully pressurise the boiler to 135psi no problem.

I rigged up a gas burner in the bottom of the firebox and raised steam, albeit slowly to avoid the flame snuffing out. It took about 25 mins. to achieve full pressure and to be able to set the homemade Gordon Smith type safety valves set to 90psi.

The handpump in the sidetank and the LH injector both worked fine but the other injector wouldn't work at all, just overflowing with a distinctly "milky" looking discharge. I was pretty sure this was going to be due to air being drawn in, but statically there were no water leaks from anywhere and no loose coonnections in the water feed system to this injector, to give any clue where air might be getting in.

To cut a long story short, the problem was with the threaded cap at the bottom of the injector water valve. It is a commercial item and air was getting in around the threads which I obviously hadn't sealed properly after I'd taken it off to have a look inside!



Next I removed the inner dome cover and spent some time improving the "flatness" of the regulator valve faces. Eventually I was happy that I'd done a better job and having sealed the water valve cap threads, a further steam test showed that both of these particular problems were resolved.

A few other minor things were also put right....the ball in the Whistle Valve was re-seated to stop it leaking, one of the injector steam valves was re-seated for the same reason (both also commercial items) and as you'd expect after the first steamings, various valve gland packings were dealt with as things relaxed with the heat.

All in all a success, so next job will be to replace the superheaters etc. and see if the wheels go round! After that, it can be presented for the 1.5 x hydraulic and steam tests to be carried out formally. Better get myself geared up to light a coal fire!

Cheers for now   Don

[coniston]

Great perseverance Don, glad you had success.
Talking to one of our boiler inspectors, who is a very experienced model engineer, some time ago when I last had a hydraulic test, he said it is almost impossible to seal the regulator (sliding plate or rotating disc type) as when under water it can lift off the seat, something to do with the effect of liquid as opposed to gas (steam). Any way I tend to blank the steam outlet of the super heater that way the super heater also gets pressure tested (regulator open) which is a recommendation in the boiler test code.

Keep going

Chris D

[don9f]

Hi Chris, thanks for that....I was thinking that whilst the superheaters are out of the boiler, I might make a small alteration to the short pipe from the dry header to the steam inlet to the cylinder block i.e. fit an additional nut / cone to enable this short pipe to be taken off and the dry header outlet blanked off. The elements can then be tested easily in situ. As currently made, this is not possible without bending said pipe out of the way....that’s no good at all!

Cheers Don

[don9f]

Hi all, time for a bit of an update....Last time I was ready to refit the superheater elements and mentioned about modifying the pipe from the hot header to make it easier to blank them off for testing. Well I decided not to do this but whilst they were removed from the boiler, subjected them to their own hydraulic test to 200psi for my own curiousity / peace of mind etc. These are the new welded elements from Polly Models and I am pleased to report that they were completely leak free! The original ones I made have been scrapped:-



Having "boxed up", it was time to actually turn the wheels under steam! Again it was only with a gas burner up the firebox as I didn't want to dirty everything up before its official test (booked for this coming Sunday).

Here is a link to a short video clip of its first runnning:-

One other job completed today was the making of a new safety valve cover. I wasn't satisfied with the shape and size of the original, so looked around for something to make it out of....anyone with a good memory may recall this photo from another thread some time ago:-



Its the broken remains of the main manifold shutoff valve from 6233 "Duchess of Sutherland“, I made a new one for it last year. Whilst turning it today, I encountered some slag inclusions in what had been the main valve face....even the LMS/BR had problems getting perfect castings!

Anyway it doesn't really matter and a bit of filler / paint will hide what shows:-



Here are the old & new, the fastenings are 1.2mm hex screws from Knupfer:-



I'll see how it goes Sunday and report back....

Cheers for now Don

[Deleted]

Excellent progress Don...I bet you had a big smile on your face when raising steam...congrats.

Pete

[don9f]

Thanks Pete, I knew it ran on air and knew the boiler steamed ok, but it was still a “Momentous Occasion”, one of many I have been involved with in connection with steam engines!

Don