Chris's Diesbar Engine Build

[crueby]

Interesting method.  I'm having a hard time wrapping my head around it now, but I assume it will become more clear as you move forward.  I'm looking forward to it!   

Kim

Yeah, it took me a long time going through the videos and pictures of the original engine to figure it all out. Its kind of like the very early big pumping beam engines that had a 'driver' to manually move the valves at startup. I'll  post a sequence later on with details of how it works. Assuming I get it to work! 

[cnr6400]

  re running - just be sure to send shop elves Engine Eckhard or Valvegear Viktor down to the operator position, and not Bucket Bob or Lifting Larry...

[crueby]

Lots more done on the release mechanisms. With the side cover plates screwed on, a small end mill was used to cut the slots from the center holes out to the inner edge of the straps and up/down to the ends. This was done in a few passes, the tiny end mills prefer a shallower cut or they can flex too much.

Then drilled two more holes in each piece. The one on the right, near the bottom end of each part, is for a screw to hold the end of the bar that goes back to a leaf spring at the rear of the engine. This spring pushes the eccentric arm forward, to keep the post on the link plate in the notch in the center of the release. The lever arm that will go in the center slot of this release can be pushed by the engineer to push the release block back, so that the vertical slot lines up with the post, releasing the post from the eccentric arm and allowing the engineer to move the valve manually. The control rod that moves this lever arm has a step on it that holds it in the released position, where the end of the lever comes out flush with the long slot so the post can slide up/down freely. I'll show that in action later on when all the parts are done. The hole on the left, towards the top of each block, will hold the pivot for the lever arm.

Then cut the recess into the block that will hold the lever arm and the end of the spring rod.

With the cover plate back on, you can see the opening where the end of the lever comes through to push on the post:

Then it was time to shape the outer profile on the blocks:

The front side was notched to form the top posts

Then the back side was notched to form the other side of the posts

and the angled sections milled away one at a time

Here it is after some corner rounding on the belt sander

Then drilled/milled in the slot for the control rod, one end will connect to the lever arm, the other end has a handle for the engineer.

And here are the two parts after being cut apart. Last step on them will be to drill/tap the hole in the top end to attach them to the eccentric arms. Then I can start making the lever arm and control rod...

[cnr6400]

  Some complex bits there Chris! 

[crueby]

Thanks 
Jeff! 

[crueby]

After lunch I got the blocks drilled/tapped and installed on the arms:

and the link plate posts and eccentrics installed on the engine

Here is a closer view of how the post on the link plate sets into the horizontal slot in the release block:

The hole in the end of the post allows another linkage to be attached, going up to the manual reversing lever that will pivot on the front vertical frame post, and extend out the front of the engine. These levers are the ones you can see going up and down in the videos from Michael.
And here is what it looks like when the block is pushed back, letting the post ride in the long slot so the engineer can manually move the valve with the lever. I still need to make the release lever, handle, and the manual lever/link.

I engaged the blocks on the posts one at a time and manually turned the crankshaft over to check the trave. The one on the right is fine, but the one on the left goes downwards just a little too far, maxing out the valve travel. So, I need to pull that one back off and shorten the arm a little bit. Both eccentric arms need to come off anyway to continue work on the levers. All that can wait till tomorrow!

[cnr6400]

 

[Michael S.]

Well done, Chris.
Now that I can see the parts up so close, their function is slowly becoming clear to me.

Michael 🍻 

[crueby]

Well done, Chris.
Now that I can see the parts up so close, their function is slowly becoming clear to me.

Michael 🍻 

Great!  It took me a long time studying the pictures and videos.

[crueby]

And, I should have studied the pictures and the CAD model a little more. No big problem, but it turns out the lower-middle screw I added for the spring rod is in a bad place, and I'll have to plug that hole. When I made a template for the release lever, I realized that it will interfere with that screw as the lever moves. Here is the template (cardboard) in place in the opening, after I milled back the back side of the opening a bit more for clearance. At the lower/left of the template, you can just see the screw hole it covers. In this picture, the lever is in the position where the post is pushed out of the operating position and into the manual valve movement position.

Why not just trim back that corner of the lever? Well, when the lever is swung over to the running position, the lower right corner would still cover it. And, the right hand edge of the lever has to fill the running position slot so the post can slide up and down without catching.

Its not a big issue, I will just plug the one one hole, and use the lowest hole for the spring rod.
Next step is to machine out the actual levers from thin stainless flat bar. I've drilled the pivot holes in the bar, and used those holes to bolt the bar down onto the same plate that I used for earlier parts. This plate will attach to the rotary table with T nuts and a center post, and allow me to rotate it to the angles needed for the shapes on the lever. I don't need any of the pivots to be on the center axis of the rotary table, which keeps it all simple.

So, next I'll start the milling process on the levers. It will likely take a little finish filing to fit them into the release blocks...

[Kim]

Sounds like a good plan for recovery with the plugs.   

The release lever is an interesting little piece there. I think I'm starting to understand what's going on.  I'm just waiting for it to all come together for the grand reveal!

Kim

[cnr6400]

Sorry to hear about the minor setback. Glad to hear you can add that to-scale feature , the P-Lug, to make it even more realistic!    (it's all in how you spin these things)   

Just kidding around, looking forward to seeing the next assembly after the fix. 

[crueby]

Thanks  guys! The sparkyp lug was too big, and I  am out of spare lug nuts, so the p-lug will have to do!   

[crueby]

A lot of fiddly work this morning on the release linkages. I took a fresh look at the lever shape, and relaized I was making it too complicated, and that I could just file/sand them from some strips of tool steel! Here is what the shape ended up as:

When assembled into the block, and with the lever in the 'disengaged' position, pushing the post out into the vertical slot so the valve can be manually moved:

and in the 'engaged' position, where the post would be in the horizontal slot and moved by the eccentric:

To move the release levers, there are control levers that pivot on the ends of the release levers, and go through slots in the blocks to where the engineer can reach them. I bent the ends of some stainless strips to reach over and next to the release lever ends and drilled/tapped holes in the ends.  Some 1-72 nuts and bolts complete the connection.

To hold the release lever in the disengaged position the control lever has a notch that lets the control lever drop down and hook on the block, holding it in place. Here I have rough sketched where the notch will be, later I will come back and file in the notches. Also, the outer ends of the control levers need to get drilled for handles, and cut to final length. Then I will make the rods that go from the lower back of the blocks to the leaf springs on the rear of the engine frame. Then I'll be able to do final (hopefully) assembly of these pieces, and start in on the manual valve levers, which link the the ends of the same posts that these blocks engage. A lot to this mechanism!
These two pictures show the real engine, with all the linkages in place:

[cnr6400]

  Top notch! (and top lever and top operating rod too) ... Looking great Chris.