TFW’s workshop

[Tim Watson]

The cylinders have now been fixed to the frames on the NER 4-6-2 class. I decided against trimming the top of the cylinder but cut out the underside of the thick running plate instead. This gave a ‘cradle’ to support the cylinder whilst it was being soldered to the mounting pad.

The two components were held in place by hand against the frames, after tinning both pieces, but wearing two nitrile gloves. These don’t give that much heat insulation, but better than nothing. The alternative, which I tried on the second side was to use a piece of emery cloth to grip the cylinder and push it against the frames. The gloves worked better and the cylinder was just tacked into place with an exceedingly hot iron.



The assembly was then removed, clamped up with some locking tweezers and properly sweated together.


An air gap was cut around the cylinders using a fine bur and files to insulate from the bodywork (actually only needed on one side - the other is live). The cylinder had a small rebate cut into it so that it did not touch the valence: this may be coated in epoxy resin later on.


The positioning of the cylinders is very critical, the first one was OK, the second more tricky. From the front they look OK.

From the side the angulation is quiet subtle: the sighting rod helps to check it out.

Next bits to make will be the cylinder covers and slide bars. The rear cover is actually quite deep and incorporates the stuffing box, which will make constructing a bit easier.

I really need to get a high resolution copy of the works photo of 2400; it has some good details in it.
Tim

 

[Tim Watson]

I do like making the ‘engine’ bits on steam locos. The slide bars are now 50% complete on the NER 4-6-2 class. I always make these types of slide bar as part of the cylinder back cover. The steel rod was drilled 1.9mm and then finished to 2mm diameter with a flat end mill. This gives the distance between the slide bars.

This was then turned down to 3mm diameter: the distance over the slide bars and then the actual cylinder diameter. This was reversed in the collet and turned down to 1.5mm - the bore of the cylinder. Finally, a 0.5mm hole was bored for the piston rod.

The next job was to cut down the sides of the ‘tube’ using a diamond disc to reveal two rather rough slide bars.

After some careful filing, using the piston rod to make sure everything is in-line and central, the slide bars are complete on one side - just got to do the other now.

The motion support bracket will help to protect the vulnerable ends.

Tim

 

[Richard Taylor]

I am very much enjoying this approach to loco construction, by way of sacrificial components. Even though sometimes my inadequate brain can only describe what you’re doing as “take a lump of brass and file away everything that doesn’t look like a Raven Pacific…”

 

[Tim Watson]

“take a lump of brass and file away everything that doesn’t look like a Raven Pacific…”

Inside every lump of metal there is a shape trying to get out…

Tim

 

[simond]

Inside every lump of metal there is a shape trying to get out…

Tim

this is true. Unfortunately, in my case it’s not always the shape I want…

 

[Ian@StEnochs]

Inside every lump of metal there is a shape trying to get out…

Tim

Michelangelo did exactly the same but with marble!

Ian.

 

[DavidB]

Inside every lump of metal there is a shape trying to get out…

Tim

Eric Morecombe - 'all the notes are there, not necessarily in the right order'.

 

[Tim Watson]

I never said it always works! I made four of the slide bar tubes to get two how I wanted them. The others were useful practice.

Tim

 

[michael mott]

I never said it always works! I made four of the slide bar tubes to get two how I wanted them. The others were useful practice.

Tim

Ah yes the apprenticeship program in action, I imagine that the collective scrap parts bins of this forum could weigh quite a bit.
Michael

 

[Tim Watson]

The motion support brackets for the Raven Pacifics was quite a chunky affair.

These were made from some 1mm thick steel - two pieces sweated together with soft solder. A number 6 cut Valorbe file with a safe edge was used to produce the rebates on the front edge of the bracket, which support the slide bar ends. Finger nails make good filing guides. All the soft solder must be removed before trying to silver solder.

A simple jig consisting of a hole in a lump of brass acted as an analogue for the cylinder, resting the slide bars on the bracket rebate.

This was then transferred to the charcoal block, a small amount of silver solder paste added and the joint heated with a fine flame.

The bits that might stay bright were cleaned up, but the rest of the bracket was left fire stained and black - saves painting.

The whole front end is beginning to get a bit more busy. I might thin the bars a little, when I have a fresh pair of eyes: taking photos is very useful for showing up dodgy bits.


Tim

 

[michael mott]

Dodgy bits, you say! Pray tell inquisitive minds need to know.

Inspiring work Tim.

Michael

 

[Kylestrome]

Dodgy bits, you say! Pray tell inquisitive minds need to know.

Tim's dodgy bits (!) are what anyone else would call perfection.

David

 

[Tim Watson]

If you compare this photo with the previous, Michael, you will see that the slide bars are now correct thickness and the angulation is better.


Tim

 

[michael mott]

Thanks Tim that’s great, it is amazing what such small changes can do.

Michael

 

[Richard Taylor]

A question to Prof Tim if I may, and apologies if the answer is upthread, but from where do you get your raw metal bar and sheet stock for projects such as the Raven 4-6-2? Was it the late Eileen’s Emporium, or do you have another preferred supplier? Thanks in anticipation.

Richard

 

[Rob Pulham]

A question to Prof Tim if I may, and apologies if the answer is upthread, but from where do you get your raw metal bar and sheet stock for projects such as the Raven 4-6-2? Was it the late Eileen’s Emporium, or do you have another preferred supplier? Thanks in anticipation.

Richard

Hi Richard,

I can't say where Tim get's his materials from but Paul has just asked a similar question.

See this thread

 

[Richard Taylor]

Hi Richard,

I can't say where Tim get's his materials from but Paul has just asked a similar question.

See this thread

Much appreciated. I followed the link to Metalsmith - terrible website but they do have a lot of useful stock listed in nickel-silver & brass. Couldn’t see any steel stock though.

 

[simond]

Maidstone model engineering,

or online sellers like

“Metals are us”, ”Metals 4 u”, ”the metal store”

hth
Simon

 

[Tim Watson]

Those are also the ones I use, Simon.

Tim

 

[Tim Watson]

It’s always a great feeling when a loco has a good first run on the MRC test tracks. The Skittle Alley easily started and ran with 18 on. She will probably take more but the loco and tender are minimally lubricated, so I didn’t want to push it.

Tim