My A J Reeves Bolton Triple Expansion Engine

[Kim]

Great milestone.  It moves very smoothly and quietly!  Very nice!   

Kim

[Admiral_dk]

Great to see how well it moves 

Per     

[crueby]

Excellent!

[RReid]

Buttery smooth! I like the Ti cladding too, looks great!

[simplyloco]

Air Pump Actuator Links.

I finished the links, apart from the final facing operation, and did a trial fit.  The air pump body is just too fat! I should have taken more off the rear face, and this would enable the rocker bearing to fit properly on the Standard. It will also bring the RH link more perpendicular to the base. I'll take the body off tomorrow and do the necessary. 



EDIT. I didn't make an error: as I suspected, the drawing is wrong.  The scribed line is where the rear face should be relative to the bore centre. It is spot on! I can't take any more off without ruining the holes positions, so I'll just 'adjust' a few things...
GRRR...!

[simplyloco]

Suitably 'Adjusted!'
EDIT. I found and fixed the knock: loose nuts...
https://www.facebook.com/1045066958/videos/pcb.3556779957943444/1038770103808417

[crueby]

Been there, just the other day! Will be there again I'm sure!


 

[simplyloco]

Today's work: Slide Valves
Three in number, and they are supplied on a stick. The ME notes suggest that they are separated and machined individually. He's surely not a machinist as we all know that similar parts should be kept 'on a stick' as long as possible, don't we ? !
Some pics.





And this is where they go! This is the low pressure cylinder valve chest.


Following up the 3/16" endmill with a round rasp, just for appearance's sake!


A spot of rough die sinking courtesy of the Proxxon mill.

[Charles Lamont]

Just a thought - seems those valves have a lot of unnecessary metal on the back, reducing the steam capacity of the valve chest. 

[simplyloco]

Slide Valve Buckles
I've never seen buckles in a model steam engine before. They might stabilise the valve, but all I can see is an increase in the reciprocating mass, thus limiting revs, and impeding the steam entry from the IP cylinder! Still, they are on the drawing, so I will have to incorporate them.
Some pics.

Back to the Proxxon. If anyone tells you that they can't get a finish like this with their Proxxon mill, suggest that they tighten up their nuts!


Components waiting to be married up.


I could have just chamfered the corners of the valves, but what the hell...!


Assembly fitted where it should go. There's not a lot of room left for the steam entry on the side of the chest. Looks like I will have to round the buckle corners.

[internal_fire]

I've never seen buckles in a model steam engine before. They might stabilise the valve, but all I can see is an increase in the reciprocating mass, thus limiting revs,

That is the first time I have ever heard anyone suggest that a model steam engine does not "rev" enough. The usual concern is going slow enough so that the motion is not a blur. 

Gene

[simplyloco]

I've never seen buckles in a model steam engine before. They might stabilise the valve, but all I can see is an increase in the reciprocating mass, thus limiting revs,

That is the first time I have ever heard anyone suggest that a model steam engine does not "rev" enough. The usual concern is going slow enough so that the motion is not a blur. 

Hi Gene.
I didn't suggest that this engine will not rev enough - 900 rpm should be about right, it's just the (excess?) lumps of metal whizzing up and down that I don't like!
John

Gene

[ettingtonliam]

Yes, I think you could with some effect thin down the left hand side of the buckle to give incoming steam a better flow path. I had to do the same on my 7 1/4" model of Locomotion. I suppose you could mill a couple of pockets in the back (side nearest the cover) of the valve to reduce the weight a bit. Its too late now, but driving the valves via a block in a slot, a la Stuart Turner would have given a lighter arrangement than valve and buckle, and better steam flow too.

[Jasonb]

As i posted elsewhere

"A lot of traction engine models have buckles both for valve and regulator, even Minnie (round).

One reason for their use is to reduce the overall height of the valve as you only have the diameter of the rod passing over the valve, if they were the typical bar type nut you need to allow for the material either side of the threaded hole in the nut above the cavity, buckle puts this width above the thin lip around the edge."

The other thing with a buckle like you have with two holes is that it is less likely to wobble on the valve rod than a bar type nut with it's single hole and as these are quite wide valves you will get more even opening if the edge of the valve and it's cavity remain parallel to the slots in the port faces

[simplyloco]

The other thing with a buckle like you have with two holes is that it is less likely to wobble on the valve rod than a bar type nut with it's single hole and as these are quite wide valves you will get more even opening if the edge of the valve and it's cavity remain parallel to the slots in the port faces

Thanks for the info Jason. I get it now!
John