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3 1/2 inch small boilered TICH

Construction of TICH according to the words and music by LBSC

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J Hancock10/01/2018 17:50:05
179 forum posts

Just a few thoughts for when you come to put the boiler together.

If you want to bring the 'spear' of the superheater tube into the firebox then perhaps consider silver-soldering

a small pre-tapped bronze plate to the top of the firebox. The 'spear' is attached( screwed) to the block.

The purpose is to prevent the 'spear' overheating with obvious result.

Consider how/what type of firedoor you will fit and best way to fit it.

Consider best type of regulator to fit and how.

Ryan Norton15/01/2018 14:12:24
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168 forum posts
655 photos

Hi J

Thanks for your advice. Based on what you have said, the superheater would then need to be made longer to get it into the firebox. I assume that by attaching the spear to the firebox top, the thermal mass of the boiler would prevent the spear overheating? Surely by attaching it though, it would reduce the effectiveness of the superheater altogether?

In chatting to some of the guys at my local club, it has been noted that special measures should be taken to prevent the superheater from touching the flue sides for this very reason.

What are your thoughts?

In terms of the regulator, and fire door, I will be doing these based on the "Words and Music" as depicted below.

tich - superheater and regulator ga.jpg

In terms of the firedoor, instead of screwing directly into the backhead with "plumbers jointing" i will make separate bushes to accept these screws which will be silver soldered into the backhead.

Ryan Norton15/01/2018 14:21:10
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168 forum posts
655 photos

This past weekend I managed to do a bit of work on the crown stays. They are now 95% done.

I need to do a bit more careful bending before riveting to get them exactly right.

The same procedure as the rest of the boiler plate work was followed. mark out, cut out, file to size, drill holes, anneal, bend, repeat.

Finally they were pickled in citric acid and cleaned with a brass wire brush.

Both stays came out pretty much exactly the same.

crown stays 001.jpg

crown stays 002.jpg

crown stays 003.jpg

crown stays 004.jpg

crown stays 005.jpg

crown stays 006.jpg

J Hancock15/01/2018 17:41:44
179 forum posts

Just an observation and (another ) point for you to consider.

I have a few 'problems' with the 3/16" tube from the regulator being screwed into the tubeplate bush.

Consider extending it through the bush 'as tube' but using a silicone O-Ring to seal it , in a properly designed recess in the bush.

All connections are now made accessible in the smokebox.

I see the superheater spear is stopped well short of the firebox ,that's ok, a safe play.

Ryan Norton17/01/2018 10:17:01
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168 forum posts
655 photos

Hi John

Are you referring to something like this? John Baguley posted this drawing on ModelEng Proboards.

steam pipe.jpg

J Hancock17/01/2018 13:14:51
179 forum posts

Yes, that is the idea.

In your case , the O-ring must be silicone, or perhaps a PTFE ring, will cope with the tubeplate temperature well enough.

Easy to experiment with different materials ,if necessary.

Doubletop17/01/2018 19:11:16
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322 forum posts
4 photos

In the same setup as Ryans drawing I was advised to use a PTFE ring, by a guy who has made in the order of 30 boilers and fixed no end of others. I had an "OK if you say so" moment but went ahead and did it.. I've never had a leak and the wet header tube comes out easiliy if needed.So no experimentation require PTFE is recommended.

Pete

 

Edited By Doubletop on 17/01/2018 19:11:38

John Alexander Stewart17/01/2018 21:21:17
661 forum posts
49 photos

Hi Ryan;

Just to add support to two recent posts:

1) My Tich - I did do the "screw-in" thing, but my regulator was a coarse thread 1/4", screw-down regulator (much like the blower valve, but larger) and it works fine. It's a large boilered Tich, so the regulator is like LBSC's Disc in a tube regulator, but with the screwed spindle.

2) I'm re-starting my 3-1/2" Martin Evans designed "Ivatt" and will most certainly use Doubletop's message - the boiler is done and tested, but PTFE ring not made yet.

On the Tich, sealing the regulator with all of those threads is a bit of an issue, and LBSC did not have PTFE or other newer materials available to him.

Oh, and you are GOING TO BUSH ALL holes where things thread into the boiler? Screwing directly into copper sheet is now recognized as a bad thing to do.

John.

julian atkins17/01/2018 21:52:15
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1172 forum posts
352 photos

Hi Ryan,

Your LBSC drawing on 15th January of the regulator arrangement would not be ok on a new build in the UK or Australia.

Instead of the copper backhead and smokebox tubeplate being threaded, bushes are now required which are threaded and silver soldered to these plates (the threading is only partly done before silver soldering the bushes to the plates).

The threaded smokebox end of the regulator steam pipe into a further threaded bush is quite tricky to do, and so I would also recommend John Baguley's arrangement.

I would silver solder a bronze tube to the smokebox end of the copper regulator steam pipe. (The regulator pipe should be of thick wall copper tube to accept the thread to screw into the regulator valve body). A screw driver slot can be added to the smokebox end which if bronze will be undamaged.

I am very interested in Pete's use of a turned PTFE bush to seal the smokebox end between regulator steam pipe and the wet header.

Cheers,

Julian

Ryan Norton18/01/2018 06:28:06
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168 forum posts
655 photos

Hi Julian

This is something I have considered and thus far ignored for the time being. wink

With that said, I will be bushing all areas that require threaded connections, including the safety valve spring piston linkage.

The boiler will be constructed similar to the one shown below.

3656-j.jpg

3656-k.jpg

3656-l.jpg

3656-m.jpg

3656-n.jpg

I do also think that the top gauge glass fitting will be silver soldered as well, similar to above but more along the lines of the original and screwed to the boiler before soldering.

J Hancock18/01/2018 09:19:00
179 forum posts

The other choice to make.

Do I pre-drill and tap the regulator +dome bush before fitting them to the boiler ?

Ryan Norton19/01/2018 06:00:22
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168 forum posts
655 photos

Morning John/ Julian

I reckon I would drill and tap the regulator and dome bush before fitting to the boiler, it would be easier for me.

In terms of the attachment of the regulator stand to the boiler barrel, I would assume that this is no longer standard practice? I am referring to the GA above.

What is the modern standard?

Any advice would be appreciated.

Thanks,

julian atkins19/01/2018 10:07:55
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1172 forum posts
352 photos

Hi Ryan,

I have always drilled and tapped the dome bush, regulator bush on the backhead, and regulator bush on the smokebox tubeplate before silver soldering.

I have always used hard drawn phos bronze for these bits. The usual tip is not to fully complete the tapping in case the threads get damaged by the long heat ups on the boiler and repeated dunking in sulphuric acid. I have never had this problem, but it might be more of a problem if you use gunmetal for these bushes.

The regulator stand is ok because the fixings are tapped into it and not the copper.

One of my least favourite jobs is making all the fitted bolts out of stainless for all the fixings.

Good luck!

Cheers,

Julian

Ryan Norton19/01/2018 12:22:50
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168 forum posts
655 photos

HI Julian

Would copper for the various bushes be OK?

Also, excuse my ignorance but "all the fitted bolts out of stainless for all the fixings"

What are you referring to here?

Regards,

Ryan

julian atkins19/01/2018 13:32:48
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1172 forum posts
352 photos

Hi Ryan,

You can use copper and I note you appear to have some big pieces noting how your firehole ring was turned out of solid. LBSC often used copper for the dome bush.

Personally, I hate turning copper, and drilling and tapping it even less. Save the copper for something else.

The fixings - you will need bolts to hold the dome to the dome bush. Brass screws are not strong enough. I prefer to have an unthreaded plain shank up to the bolt head which aids sealing. Commercial bolts in stainless will probably be undersized on the thread, and won't have an unthreaded portion, and the heads will be too big and will interfere with the dome itself. So I make them all myself out of stainless hex.

Cheers,

Julian

J Hancock21/01/2018 18:32:44
179 forum posts

As Julian A , avoid copper bushes and any form of leaded bronze bushes.

J Hancock21/01/2018 18:34:56
179 forum posts

Should have said, if you are in any doubt about material, try silver soldering it on some 'scrap' item first.

Ryan Norton06/02/2018 15:48:02
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168 forum posts
655 photos

I have done some more work on Tich, this time on the brake gear.

I'm sure you would have all seen the naked brake shaft in some of my previous pictures of the full locomotive.

The first item made was the drop arm, this was marked out, drilled, cut out and then filed to final size.

brake 008.jpg

Next, the two actuating arms were made. As these needed to be exactly the same in every respect, two plates were soft-soldered together and the operations were performed on both arms at the same time.

brake 009.jpg

brake 010.jpg

Above you can see the fine line where the soft solder is.

The shape was then rough cut with a hacksaw.

brake 011.jpg

Filed with a bastard file.

brake 012.jpg

brake 013.jpg

Then filed with a second-cut file.

brake 014.jpg

brake 015.jpg

Finally finished to shape with a smooth file and the edges draw-filed.

brake 017.jpg

brake 016.jpg

The small hole at the small end was lengthened into a slot to accommodate the changes in radial length as the nut is screwed up and down.

brake 018.jpg

Finally the two pieces were separated with a bit of heat.

brake 019.jpg

Cleaned up.

brake 020.jpg

and then test fitted to the shaft and locomotive.

brake 021.jpg

The whole lot was then silver-soldered, remembering the square nut between the arms before soldering.

brake 022.jpg

brake 023.jpg

 

Edited By Ryan Norton on 06/02/2018 15:59:24

Ryan Norton06/02/2018 16:48:43
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168 forum posts
655 photos

At the same time I fabricated the the brake column and spindle with all the various components.

See the pictures below of the various stages of work.

brake 001.jpg

brake 002.jpg

brake 003.jpg

brake 004.jpg

brake 005.jpg

brake 006.jpg

brake 006a.jpg

brake 007.jpg

brake 025.jpg

brake 026.jpg

Instead of pinning the brass collars to the shaft I made M2 x 1mm long grub screws which hold the collars to the shaft.

brake 027.jpg

brake 024.jpg

brake 028.jpg

Neil Wyatt06/02/2018 17:05:51
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Moderator
12517 forum posts
557 photos
66 articles

Lovely work Ryan.

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