Hi and Andrew Barclay model engine

[stevep]

Most fixed steadies open up to allow this.

[ettingtonliam]

If its one that doesn't, I would (shock, horror) saw a slot in the casting to allow a shaft to slot in. Many older small lathes had fixed steadies which didn't have a hinged top, but had a slot cast in.

[Kevan]

Here is the set up I used for the leading axle

Eventually I got it to run true.

Unfortunately as soon as I started cutting the pin preventing the wheel rotating sheared and the wheel came loose. So I did these straight in the 4 jaw gripping the flange.

For the driving and trailing axels the crank pins prevented gripping the tyre. So out came the crankpins, one took serious force! Once they were out, one of the wheels sat flat in the chuck gripped by the flange allowed light cuts on the other without trouble.

What I didn’t realise was how bad the castings for these wheels are. Once I scribed a circle on the rims it showed how irregulary the spokes met the rims so about an hour and a half of dremmeling has helped tidy them up. I have decided to follow the prototype and paint the rims so they are primered.

Having a loose wheel on the leading axel opens up the possibility of an eccentric for a water pump. Once I have returned the wheel sets to the frame I will see what space is available. I guess something like the William pump would deliver enough water.

Cheers Kevan😃

[JonL]

Good lighting on your lathe! Very jealous!

[Kevan]

Progress report. Wheels and rods painted and back in the frames. Cylinders stripped cleaned in paint thinners, faces cleaned and lapped on wet and dry on the glass table😃


For some reason the right hand cylinder and crosshead are quite rusty so they have been consigned to the de rusting solution overnight. The cylinder cover on the right side is brass and on the left steel. Also the cylinder castings are a bit crap. There seems to be some porosity in the valve faces showing as small black specks even after lapping. No sign of these in the cylinders though.

I am waiting for drain cocks from Polly engineering before I start reassembling. After all the gunk has been removed the piston fit in the cylinders is a bit looser than I expected. Another aberration is that the piston rod fits to the crosshead with a nut and bolt rather than the taper pin in the book. Should I change this?

Kevan🤔

[stevep]

Kevan,

That looks very tidy.

I shouldn't worry about the black specs, as provided the flaws don't go right through, it will be fine.

I also wouldn't worry too much about the piston fit - that will be taken up by the rings or packing (provided it's not too bad).

You say the piston rod fits to the crosshead with a nut and bolt. Is that through the cross-drilled hole in the picture? That is unusual, and I would think would be OK if it is a tight fit. You don't want any slack there, so it may be worth considering reaming it out and either fitting a roll pin or a taper pin.

[Kevan]

Another day another issue! Having now thoroughly cleaned the cylinders in thinners the nice shiny surface has gone away to be replaced with this
The pistons are already an ‘easy’ fit bit the covers are a good fit so I am not inclined to take a lit of metal off the bores. As mentioned the castings are not that nice and are covered with little black specks it looks like these are in the cylinders as well as on the other machined faces. What should I do to rescue these cylinders?

Kevan😟

[timb]

Could try a hone, failing that bore and sleeve if there is enough meat on them.

Tim

[Kevan]

What should I think of as the minimum thickness for a sleeve and what would be best material as in easiest to work with for that?

Thanks Kevan

[uuu]

Just leave it. Honestly, it will be fine.

Wilf

[timb]

If I was to base this on the thickness of say an oilite bush then they are about 1/16 thick for the smaller sizes, however you have to consider the integrity of the casting once you have removed enough material to fit the sleeve - specifically the threads for securing the end covers. I think I would have 1/16 as a minimum and go from there.
I would also take into account the rest of the casting and the state of the machining as to whether there would be a benefit from redoing the lot.

Others may have a different view, I would think there will be more advice before the day is out.

Tim

[stevep]

I'm with Wilf - leave them. You said that one of the cylinders is rusty - does that mean they are cast iron?

If so, fit the pistons with proper rings, and the bore will soon polish up nicely.

[Kevan]

I believe they are cast iron. The pistons are brass and are grooved for 1/8” graphited packing rather than rings.

[stevep]

Jun 18, 2020 16:37:08 GMT Kevan said:

I believe they are cast iron. The pistons are brass and are grooved for 1/8” graphited packing rather than rings.

If the bore is rough, it will tear soft packing. Re-machine the pistons to take proper rings, and everything should be fine.

[uuu]

Just to reassure you - here's a picture of Jessie's cylinder end cover. You can see it has the same mottled appearance:

JessieCylinderEndCover by Wilf, on Flickr

It doesn't feel rough at all.

Wilf

[steam4ian]

Jun 18, 2020 15:20:29 GMT Kevan said:

Another day another issue! Having now thoroughly cleaned the cylinders in thinners the nice shiny surface has gone away to be replaced with this
The pistons are already an ‘easy’ fit bit the covers are a good fit so I am not inclined to take a lit of metal off the bores. As mentioned the castings are not that nice and are covered with little black specks it looks like these are in the cylinders as well as on the other machined faces. What should I do to rescue these cylinders?

Kevan😟

Your thinners have washed off the heavy oil coating that was on the walls. Considering the low cost a brake cylinder hone I would buy on and give it a go. You have almost nothing to loose and a lot of work to avoid. The surface appears like it would cut away packing or O rings.

[uuu]

I wouldn't touch it. Get it running and try it out. If it became all shiny and smooth before then it will again. Only if it keeps eating the packing will you need to take action.

Wilf

[Kevan]

This weekends activities include a visit to the only accessible pug during COVID

Sadly not in good condition but useful to look at for details. This is at Polkemmet where it worked. First the wheels


How did they cast these and how would you do this for a model?

The brake rigging is way simpler than Martin Evans describes for Rob Roy. The cross beams are simple bars
, the pull rods are rectangular section with no adjustment held on with collars retained by set screws! The hangers are simply retained by split pins. This locomotive had only a handbrake not even a steam brake!


Other interesting discoveries were that all 4buffers were different! The rear buffer beam was bent and cracked. Goodness knows what kind of impact caused that.

Today was spent making swarf. The only thing I had to make brake blocks was an old cast pipe flange. What horrible metal! At slow speed on back gear I could only manage 10 thou cuts and even then I broke a lot of carbide. tips in the end I used a high speed steel bit which seemed to keep its edge better. Last thing was trying to cut a slot with a parting tool. No chance! Any idea how I should make an edge on it that might actually cut rather than chatter?

Thanks Kevan

[Jock McFarlane]

Jun 21, 2020 20:56:52 GMT Kevan said:

How did they cast these and how would you do this for a model?

The brake rigging is way simpler than Martin Evans describes for Rob Roy. The cross beams are simple bars
, the pull rods are rectangular section with no adjustment held on with collars retained by set screws! The hangers are simply retained by split pins. This locomotive had only a handbrake not even a steam brake!


That is an interesting arrangement of the balance weights. Looks like they have been designed in the simplest possible way to balance the rotational masses but no allowance is made for reciprocating masses. In a slow speed shunting engine i think that was normal and in miniature sizes probably makes no difference.

[ettingtonliam]

Unless you are intending to make an accurate model of a particular engine, I wouldn't worry too much about the shape of the spokes. Those are H shaped, like the old London North Western freight engines. It would complicate the pattern making no end to replicate them

Having said that, there is a chap who has a stand at model engineering exhibitions selling drawings and castings for a 5" gauge LNWR Coal tank, which in full size had H spokes. I don't know if his 5" versions do. I can't remember his name and contact details, but someone else on here probably does.