Hunslet 5 inch gauge build.

[jma1009]

[/quote]I don't think it matters a damn who is happy other than the builder and the boiler inspector.

[/quote]

1. Ok,
scrape all the paint off the smokebox to have plain
brass etc.

It would not look right, agreed?

So a brass unpainted firebox door is acceptable?!

2. The horizontal brass square tube used for the displacement tank for the steam oil. This is subject to boiler pressure via the feed from the boiler, and therefore should be pressure tested at least to working pressure.

Extruded brass square tube is not suitable.

There is also the problems with separating the oil from the condensed steam on a horizontal long 'tank'.

Far better to adopt the standard vertical copper tube cylindrical tank.

I could not see any staying of Malcolm's brass tube to make it even potentially suitable as a pressure vessel, and I consider the choice of material to be dodgy anyway, and will cause problems with the way the tank will work notwithstanding any issues of the brass square tube being
unstayed and unsuitable as brittle etc.

The first hydrostatic lubricator displacement tank I made was out of high pressure RN phos bronze tube. Always pumped them up to test them.

Cheers,
Julian

[stevep]

It may have not come over very well, but I suspect the point that Julian was making is that with a hydrostatic lubricator, the oil tank is subject to boiler pressure. A square box is not the ideal shape for a pressure vessel, and would need to be made of substantial material.

The conventional form is cylindrical (much stronger) with flat ends - possibly with a central stay. And if mounted between the frames, the ends wouldn't blow out too easily.

EDIT - just seen Julian's response.

[JonL]

And that response is reasonable. Your original post was bordering on rude.

[jma1009]

May 22, 2021 16:21:28 GMT JonL said:

And that response is reasonable. Your original post was bordering on rude.

"Rude" only because you don't know the context of my pithy remarks.

I spent a considerable amount of time checking the valve gear for Malcolm and re-designing out the errors in Don Young's original design.

I then re-designed the smokebox draughting for Malcolm.

Malcolm has made a very good job on the loco, and I don't want it to have any issues.

Cheers,
Julian

[springcrocus]

May 22, 2021 20:39:30 GMT jma1009 said:

May 22, 2021 16:21:28 GMT JonL said:

And that response is reasonable. Your original post was bordering on rude.

"Rude" only because you don't know the context of my pithy remarks.

I spent a considerable amount of time checking the valve gear for Malcolm and re-designing out the errors in Don Young's original design.

I then re-designed the smokebox draughting for Malcolm.

Malcolm has made a very good job on the loco, and I don't want it to have any issues.

Cheers,
Julian

And how sad that you feel the need to highlight your own efforts over Malcolm's exceptional engineering skills, as shown by his photos.

I agree with Jon, you could have explained this in your first post but chose to be provocative instead. You need to get back in your own workshop, Julian, and put your considerable talents to better use.

Regards, Steve

[keith1500]

Pithy remarks is the one of the reasons I don’t post anymore.

You/we post here in good faith that it will be of interest to others and gain some feedback. If feedback must be negative due to oversight or error then surely it’s polite to give some rationale. We can and all do learn from this its not unreasonable.

I hope you carry on with the build.

[JonL]

May 22, 2021 20:39:30 GMT jma1009 said:

May 22, 2021 16:21:28 GMT JonL said:

And that response is reasonable. Your original post was bordering on rude.

"Rude" only because you don't know the context of my pithy remarks.

I spent a considerable amount of time checking the valve gear for Malcolm and re-designing out the errors in Don Young's original design.

I then re-designed the smokebox draughting for Malcolm.

Malcolm has made a very good job on the loco, and I don't want it to have any issues.

Cheers,
Julian

I suspect you and I would get on very well indeed in person. We both aim for different things in model engineering (I'm a novice trying to learn techniques but not too worried about accuracy, you seem to be a very experienced engineer keen to encourage high standards) but we still have that same hobby in common, even if we apply it in different ways. 

You've been very quiet of late, which is a shame as I enjoy your posts. I would just suggest that the wording of some of the things you say, specifically with regards to others work, can come across as very abrasive and scathing. Your knowledge and experience is something I'm glad you are sharing, but perhaps it's worth just re-reading what is posted before you click send to ensure you won't discourage anyone.

I notice you don't post much on my work, which is a shame as I do think your guidance would be of great value. I just sometimes find it hard not to bite my tongue when your comments come across as scathing. Looking through your previous posts the criticisms outway the congratulations by quite a heavy margin.

I apologise for derailing this thread, however I am glad to have got my opinion out there even if it comes across as a bit whiny!

[mbrown]

Julian's blunt comments are legendary on this forum and do sometimes lack subtlety. But less well known is his considerable generosity in sharing his skills and experience with other members - usually "behind the scenes" rather than via public posts. I have personal reason to be very grateful to him in that regard, and I know others do too.

The brass firedoor is neither here nor there - like a hypothetical brass smokebox, it can be painted (or blackened) if the builder desires - although many model engineers seem to go in for bright metal where the prototypes would be painted - look at the majority of handrails!

But Julian's points about the rectangular oil tank deserve more consideration in my view. The shape is not ideal for a pressure vessel, so it will be good to hear how it stands up to a pressure test. My hunch (only a hunch...) is that the material thickness will mean it is OK.

But the ratio of the tank volume to surface area in a displacement lubricator is an interesting issue where some more experimental data would be very useful. As most such tanks have a fairly small surface area compared to volume, I suspect that such a ratio reflects practical experience. A large surface area in relation to volume could - I am guessing here - lead to it feeding big gulps of oil rather than a steady trickle. Don Young made some comments about this ratio, but only to advise builders to make the oil tank to his design - no theoretical or experimental data was given.

So I hope Malcolm will let us know how his lubricator performs in practice.

Malcolm (the other one....)

[rrmrd66]

Evening All

I have tried to not get involved in the fracas that Julian's recent post has created.

However I now feel that everybody has had their say and would respectfully ask that we now get back to the original objective of the thread i.e. the build diary of a 5" gauge Hunslet to Don Young's design.

The comments that have been made regarding the design of the horizontal square section displacement tank lubricator are welcome and I will report back in due course on its effectiveness. The alternative and more acceptable design (vertical axis cylindrical tank) is an option. Prior to being given the ME article I had made such a tank to go under the cab floor by the rear buffer beam. A soldering mishap with an oxy/propane welding torch (don't ask), the ash pan damper lever and a quick release coupling to feed the horizontal injector all conspired to thwart me.

I have had along conversation with Julian and thanked him again for all the free advice he has given me over the years, as I did not wish him to think I was in anyway orchestrating the tone of some of the postings on my thread.
He is, in fact you may be interested to learn, a delightful person to talk with and does not come over at all like his trenchant e mails.

I did point out that as Ralph Waldo Emerson said (misquoting him) that the journey for some was more important than the destination.

Prototypicality was not a major concern for me.

So come on guys, back to the workshop and get on with it.

Oh! I've just noticed. The Yorkshire Pixies stole into the workshop over night and painted the firebox door matt black. Would you believe it?

Cheers

Malcolm

[ngfan]

Hi Malcolm,

I hope the recent posts haven't put you off further postings, Anyway, I continue to follow you progress with great interest, and I thought that I would get things going again.

I've just finished the smokebox and I have attached a couple of photos below. I'd never previously flanged anything, so with some trepidation followed your procedures, making wooden formers, and repeatedly annealing the copper. It came out pretty well, apart from one expensive lesson that I've learned. I only have a small lathe (an ML10) so couldn't swing the flanged plates. I therefore mounted them on my 6" rotary table, and milled the holes for the stiffening ring and boiler joint ring. The load on the table was too great and I have managed to damage its gear ring and worm. (I have since read that if you want to attempt such a large diameter rotary milling, it's best to drill a series of holes around the periphery of the table, and then rotate it using a tommy bar.)

I silver soldered the stiffening ring to the front flanged plate. I was concerned that the heat might distort the flanged plate, but fortunately this didn't happen.

I temporarily fixed the flanged plates to the smokebox wrapper with 6BA hexagon bolts. Having now made the smokebox door, hinges etc to my satisfaction, I've replaced the hexagon bolts at the front with slotless 6BA roundhead screws in order to give the appearance of rivets. I also filled any slight gap between the front flanged plate and the wrapper with Rocol Steamseal to try to ensure the final smokebox assembly will be airtight. I will treat the rear flanged plate and boiler joint ring similarly after the boiler has arrived and I can bore the joint ring to the correct size.

The petticoat pipe is simply held on to the chimney tube with a 4BA hexagon bolt. I just hope it doesn't differentially expand in the heat of the smokebox, and fall off.

I hope you don't think I'm trying to take your thread over. Hopefully my comments may encourage (or perhaps warn) other potential builders.

Best regards,
John

www.flickr.com/photos/192090967@N05/51362684413/in/dateposted-public/
www.flickr.com/photos/192090967@N05/51362684358/in/dateposted-public/


PS I'm sorry these are hyperlinks rather than embedded photos, I just can't get the embedding to work this time

[rrmrd66]

Hi John and everyone else.

Well, now you ask I would prefer it if you started a new thread for your build.

I have basically finished the build of my Hunslet. I am about to steam it. Major problem with the regulator valve not holding pressure on the hydraulic test.

I can understand the need for safety if involved with public running and club boiler tests. However bearing in mind the stricture of never filling the boiler higher than half way up the sight glass(es) I can not get my head around filling the boiler up to the very top of the manifold and then pressurising to 50% plus working pressure (120psi). This is a thing that would never occur in normal running unless one tried to simulate "hydraulicing" of the pistons/cylinders with all its dangers. I have a new Western Steam boiler plus works certificate (to 2x WP). All seems a bit OTT to me.

I may just run it on a garden track after having set the safety valves,. The engine pressure gauge seems, surprisingly, in line with the pressure gauge on my hydraulic pump.

Some final photos to follow.

After a non stop 4+ year build, like Roger, I wanted to do something different for a bit so have built a Hemingway pipe bending kit which, as always, was not quite as easy as I thought, the 5 circular cross section bending dies being a bit tricky. Anyway I will now have beautiful copper pipe radii for my next build (Bridget).

Thanks to all those who have followed this build thread. I hope you may have learned something? I have learned LOTS!

Cheers

Malcolm

[stevep]

Malcolm, the reason for filling the boiler completely with water for the hydraulic test is that water is (largely) incompressible, so if the boiler shell were to fracture, the loss of water would immediately dissipate the pressure. If the boiler was only partly filled with water, to pressurise the shell, you would have to compress the air that was in the boiler too.

As I am sure you are aware, compressed air can be dangerous, and it the shell fractured, the resulting expansion of the compressed air could be lethal.

Quite by the way, if the boiler were only part filled, you would be pumping your test rig for a long time to compress the air. With the boiler filled right up, it only takes a couple of pumps to produce the pressure required.

[ngfan]

Hello, perhaps for the last time, Malcolm,

Congratulations on finishing your loco.  4 years seems an impressively quick time for a first time builder, and particularly of the build quality that you have managed to achieve.  I am rather in awe.  I will continue to consult this thread whenever I feel uncertain.  I won't start my own thread, but will probably pose occasional questions to this august body - as I have sometimes done in the past.

As regards completely filling the boiler for the 1.5X pressure test, I believe it is essentially for safety.  I worked in the chemical industry, and I remember an incident when our engineer was hydraulically testing a 1L laboratory autoclave, which had a lid sealed with a ptfe ring.  He made the mistake of not filling it completely full of water.  The ptfe ring broke during the test and fired a piece into his stomach, giving a very severe bruise. Basically it was a crude compressed air gun.  (It was also probably at 1000 psi!)

Anyway, best of luck with the Bridget.

John

[John Baguley]

The 1.5X hydraulic test is to test the integrity of the fittings such as the clacks and water gauges, not the boiler. You would not want any compressed air in the boiler if a fitting were to break loose. It would probably fly off like a bullet. Not nice for anyone in the way.

John

[rrmrd66]

Hello John (Baguley)

Thanks for the advice.

My problem is that I am getting water, under pressure, past the faces of the Stroudley type regulator. I lapped them in, but maybe not enough?

This resulted in water getting into the cylinders and emerging through the blast nozzle into the smoke box. Not what I wanted to put it mildly.

To get into the regulator means stripping the boiler manifold/super heater feed right back and re-lapping the faces.It has been suggested that maybe I could blank off the super heater feed but this appears to be as difficult as stripping it all out.

Frankly I am disappointed to have got this far, only to fail at the last hurdle.

The Hunslet may have to retire to the black hole under the bench!

All suggestions greatfully received.

Cheers

Malcolm

[ettingtonliam]

Cap off the blast nozzle? If its removable unscrew it and fit a blank cap. I know this means subjecting the exhaust pipework to 1.5 x boiler pressure, but desperate times call for desperate measures!

[smallbrother]

Aug 8, 2021 18:09:07 GMT rrmrd66 said:

Hello John (Baguley)

Thanks for the advice.

My problem is that I am getting water, under pressure, past the faces of the Stroudley type regulator. I lapped them in, but maybe not enough?

This resulted in water getting into the cylinders and emerging through the blast nozzle into the smoke box. Not what I wanted to put it mildly.

To get into the regulator means stripping the boiler manifold/super heater feed right back and re-lapping the faces.It has been suggested that maybe I could blank off the super heater feed but this appears to be as difficult as stripping it all out.

Frankly I am disappointed to have got this far, only to fail at the last hurdle.

The Hunslet may have to retire to the black hole under the bench!

All suggestions greatfully received.

Cheers

Malcolm

I always understood that a slight leak in the regulator would be OK providing there are no other leaks. If the rest of the boiler is dry, no sign of water anywhere, how can there be a problem?

Pete.

[Roger]

Hi Malcolm,
Very well done on getting your locomotive to this point. I would consider the problem to be a minor glitch in the big scheme of things, I'm expecting much worse when I get that far! Maybe it's not such a big problem as it seems? You wouldn't normally expect to do a hydraulic test with the regulator holding the pressure. That's not what you're testing. I'm sure you can block off the feed to the cylinders for the test.
If it leaks too much when it's in steam, it's time to dig deep, resolve to fix it once and for all, and reap the rewards of all your efforts. Once you've fully engaged with recifying the problem, you'll feel much better about it. I try not to wallow in the temporary misery these problems bring. I find it much better do dust myself off, shrug my shoulders and crack on with it. We have to go from where we are, not where we want to be.
It's a cracking locomotive, and you'll be rightly proud when it's working to your satisfaction. I only wish I was at the same stage myself.

[jma1009]

Hi Malcolm,

Please do not worry about the regulator leaking on test as I am sure the steam pipes in the smoke box can be blanked off, via various means.

I will have a look through your thread to hopefully provide some positive and constructive suggestions, but this won't be for a few days or till next weekend as I have a busy week at work ahead.

Cheers,
Julian

[John Baguley]

Hi Malcolm,

I think that I would just temporarily remove the superheaters and fit blanking caps to the connections on the wet header. That way it won't matter if the regulator weeps slightly when you test. That won't test the superheaters (you could do those separately if you wanted to) but it's not compulsory to test the superheaters anyway. Off hand, I think the code says to test the superheaters 'if possible'.

Another way might be to insert some very thin discs made from say brass or copper shim in the superheater connections to the cylinders and then tighten the joints again. That should seal off the connection and enable you to test the superheaters as well.

John