Chris's Slew-Crowd Engines

[crueby]

A little time this morning  working on the timing of the Erie engine, then went out to get more pics and measurements for the  steam crane. Traced all the control linkages and  got underneath to  see how the track clutches and brakes work. Another  600 pictures! More  on timing the engine later...


 

[Michael S.]

It is great to see how well the individual motors are working. That is a fantastic achievement on your part. 
I am very much looking forward to your next project.

[cnr6400]

 

[crueby]

And this afternoon took a little time and got the Erie engine valve timing tuned up, now runs nicely in both directions. That makes three engines up and running, just one more to go!      

<a href="https://www.youtube.com/watch?v=tBTlqn2rWTc" target="_blank">http://www.youtube.com/watch?v=tBTlqn2rWTc</a>

[crueby]

It is great to see how well the individual motors are working. That is a fantastic achievement on your part. 
I am very much looking forward to your next project.

Thanks Michael!  That Diesbar engine will be a very interesting one, a very different design than the usual engine. In researching the Brunel ship's engines, its interesting how much John Scott Russell copied from the earlier Penn designs when he created the 4 cylinder oscillating engine for the paddle wheels on the Great Eastern - almost identical valve system, only difference from the Diesbar is that the reversing is done with a Stephenson linkage rather than the slip eccentrics. And the G.E. engines are a LOT bigger, of course.  I've been thinking ahead on the Diesbar engine, making the cylinders will be a challenge with the steam chest passages coming from the pivot trunnions on either side. I think I have decided how I will make them, maybe...   

[crueby]

Thanks Jeff!  I was out at the steam crane earlier today, which got me thinking about seeing that Erie type B up at the show near you. Were you able to get in touch with the guys who own it to see if they will be running it this year?

The crane has a fairly complex and very interesting design for the track drive clutches and brakes, it looks like moving the steering lever partway to one side will disengage the clutch on one side, and moving it farther will also engage the brake band on the output shaft beyond the clutch. Moving the lever the other way would disengage then brake the other side. In the center both clutches engage to go straight. All done via a sliding tube around the vertical drive shaft down through the center of the turntable and base units. A real step forward from the way the earlier machines steered, using the cab motion to engage external clutches down on the track, on this one the clutches are right next to the bevel gears driving the tracks in the center. Going to be an interesting one to model up in CAD this summer...

[cnr6400]

  In my best Maxwell Smart / Don Adams voice "the old sliding tube over the pivot shaft trick, eh Siegfried?" re the Erie crane steering control...

Glad you had a good visit there and got some more details and pics. 

I did call the guys looking after the Erie shovel that used to be a regular at Blyth. My main contact there is semi retired now I'm told, but the receptionist / dispatcher said she would get a message to him to give me a call. Will let you know the result when he calls back.

[crueby]

In my best Maxwell Smart / Don Adams voice "the old sliding tube over the pivot shaft trick, eh Siegfried?" re the Erie crane steering control...

Glad you had a good visit there and got some more details and pics. 

I did call the guys looking after the Erie shovel that used to be a regular at Blyth. My main contact there is semi retired now I'm told, but the receptionist / dispatcher said she would get a message to him to give me a call. Will let you know the result when he calls back.

   

[PaulR]

Nice! Are we going to see all four running simultaneously or will they demand too much air?

[crueby]

Nice! Are we going to see all four running simultaneously or will they demand too much air?

I'm hoping to have all four running together, even if I need to set up the other small compressor I have for one or two of them.

[PaulR]

Nice! Are we going to see all four running simultaneously or will they demand too much air?

I'm hoping to have all four running together, even if I need to set up the other small compressor I have for one or two of them.

[crueby]

This morning I got the cylinders removed from the Thew engine, and drilled/tapped for the cylinder drains.

Wish I had done these when making the parts in the first place, getting all the screws holding the cylinder out/back in was a pain on this engine since they had to be done mostly with a 1/8" open end wrench - very slow. All back together now though! I did make a new gasket for the steam chest cover too. When I made it originally, I trimmed it a bit too close to the holes, and it tore during handling a while back. Very quick to make a new one, drilled through the gasket sheet using the cover as a drill guide then trimmed around the outside with scissors. This time I left the center solid rather than cutting out the center - will be much sturdier this way.

Here is a picture of the inside of the steam chest to show the orientation of the ports for the cylinders. Unlike the other three engines, the valve ports are vertical on the sides of the cylinders, while the throttle valve is horizontal between them. Will all work the same, just a little tighter quarters for getting at things.

I have the eccentric arms disconnected from the valve rods, and the rods pulled back to allow inserting the valves. So far I have the blanks for the valves milled to overall dimensions, ready to cut the slots for the valve rod/nut, and then the ports. Since the valve rod is fairly close to the valve face, there is less room to drill the connecting passages in the valve. I'm thinking I'll make the adjusting nut stop short of one side, to leave room for the passages. Will start on the shaping of the valves this afternoon or tomorrow morning.

[cnr6400]

    "Thewper!" as Sylvester the cat would say...

[crueby]

  "Thewper!" as Sylvester the cat would say...

Thewferin thuckitash!   

[crueby]

This morning I got the valves for the Thew engine finished up. Drilled the passage hole to connect the end chambers, then milled the chambers themselves:

Then lapped the bottom faces of the valves. Before lapping, I took a picture of the bottom face after marking it blue to show the difference that lapping can make on a valve face that was just milled flat:

Then after the first couple swipes on a diamond sharpening/lapping plate:

You can see how the tool marks from the end mill are still there and some areas have been taken down by the plate more than others. All those blue stripes would be places where air/steam could blow past the valve and into the exhaust and both ends of the cylinder. I then kept wiping it on the plate (the one I am using is designed for use with water, others use oil or some solvent - after use I flush the surface with clean water to clean away any fine bronze particles). Then switched to a finer grit plate to finish it off to a nice smooth surface.

The sides of the valves were marked to show where the walls between the chambers are, and also drew blocks to show where the ports are on the valve face. I used those marks to do the initial centering of the valve travel:

Here is the engine ready to close up and start the eccentric timing. Will do that after lunch, might have it running this afternoon. Or not - never know how long that process might take. For now I have left the caps off the guide posts for the valve rods, where the square section of the rods are. I'll do the initial test to see if the centering is good, with the drain plugs still out, then put the caps on when happy with the centering. With the caps off, the rods have just enough flex so I can rotate the rods to adjust the center position. The rest of the timing will be done after that by adjusting the eccentrics on the crankshaft.