The Sabino Compound Engine

[crueby]

Okay, good progress on the cylinder drain valves today!  Got a working and small enough setup now, so I made up the whole batch needed. Started with the ones that screw into the cylinder block, turned the end of a length of hex bar and threaded the end M4 to match the holes in the block, and drilled a #50 hole up to the middle where the cross pipe will be.


Over to the mill to drill a 1/8" cross hole through for the pipe...

and back to the lathe to finish forming the outer end and parted off

Here are the valve bodies so far, after making and soldering in the cross pipes. They were made from a length of 1/8" bar, drilled through and parted off, pressed into the holes and soft soldered. The ones on the upper right with the short cross pipes are the cylinder top end drain valves, the cross pipe in those was only drilled up to the center of the valve body, not all the way through. The ones under that, lower right, are the lower cylinder drains, they take a pipe from the upper ones, and will connect to elbows underneath. The one on the upper left, the short one, will be the stop valve for the steam inlet for the line that will run around the back of the engine to act as a bypass. Lower left are three more - the one in the middle with the long end screws into the bottom of the LP block to drain the receiver spaces. It is not a valve, just a connector and splitter. Either side of that will be two more stop valves. One leads to the condensor with the other drains, the other would lead to a pressure gauge so the engineer can see what the receiver pressure is. Thanks again to Dave for educating me on what all the valves are and where the pipes lead to!


The top end of the valves were drilled/tapped for 3-48 threads, down to just below the cross pipes. The bottom of that hole will act as the valve seat, to plug or allow steam from the long ends in the cylinder block holes to come out. Next need to make the valve stems and handwheels. The stems will be made from some 3-48 screws, with the bottom ends tapered and the ends of the threads removed to let them seat - the threads in the bodies can't quite reach the seats, even with a bottom tap. After they are installed, the valves will connect to 1/8" OD tubing, using slip fittings at the joints. I probably won't install the valves and tubing till the inlet valves are made and the initial timing work done, to reduce the chance of damaging one as the engine is tipped up on its side during eccentric timing work.
Very happy with how these turned out, they are almost half the size of how the first attempts were working out.
Chris

[crueby]

This morning made up the valve stems by turning a cone at one end of a bit of 3-48 threaded rod (cut from a SHCS), and turned/threaded a set of valve handwheels from some hex bar stock. The handwheels have been loctited on to the ends of the stems. The valves pass the blow-through-the-end test, should be okay for higher pressures. Here is the batch of completed drain and stop valves:

Still to make are the larger starting valve and even larger throttle valve...

[cnr6400]

Very nice valve work Chris! 

[scc]

    MAGIC..............Terry

[crueby]

Thanks guys!        CNR, its very slow magic, the audience would have left the theater long ago!   

Work has started on the medium size valves. These are large enough to make them more like the full size, with the center seat and offset holes either side for the in/out passages. Since they are inline valves, can't just do the seat from one end like the 90 degree ones. So, after some fiddling about, I decided to use two Tee castings that I had gotten for the Mann truck build. These were designed in Fusion, and the 3D CAD files uploaded to Shapeways for casting. To keep the part count down, and likewise the price since they charge by the piece, they were made up into groups with little connector sections between them. Here are two left over from the Mann truck, still connected into one longer casting. The side holes were drilled out and brass inserts made with the valve seats and offset holes. This is as small as I think I could pull off this sort of valve, a very short distance between different holes and diameters.  Again, the stems were made from turned down screws and the handles turned and loctited on.

For scale, those are 4-40 screws, and the holes in the tees are a little under 3/16". With the stems removed, the insides of the holes and the outsides of the inserts were tinned then soldered in place. Here they are after cleaning up, adding the handles, and cutting the two pieces apart:

When I had the pieces cast, I had put them up on Shapeways website in a 'shop' they allow for, lets other people order the castings and I get a cut of the profit for no extra work on my part. A while later, someone else had messaged me there asking for a version with 3mm openings in the Tees (also in the 90 degree elbows I had made at the same time). Those are up there as well, and I realized I needed some for the smaller drain pipes so I have ordered another set to be cast, should have them in a few weeks. Orders others have placed have made the ones I am getting effectively free!

So, that leaves just the main steam throttle valve, which is the largest of the lot. It is another 90 degree valve, and will have a  wheel with a handle on it so the engineer can quickly spin it open and closed one handed. That one will be made from two pieces of hex brass stock, drilled/threaded to assemble and solder before drilling the holes through. Here are the pieces after turning and threading the outsides:

The black screw will be used to make the stem from. Like the smaller ones, the threads were tinned, the parts screwed together, and heated again with more solder wicked in from the ends of the threads:

For scale, that is 3/8" hex bar, and the larger thread on the post sticking out is M7 to match the hole in the side of the cylinder block. I'll get it cleaned up, then next time will start drilling the holes.

[Kim]

That is fine little jewelry you're making there Chris!   

Kim

[crueby]

That is fine little jewelry you're making there Chris!   

Kim

The shop elves keep trying to steal them for their still...

[Baltic]

Another build thread I have wasted time following (64 pages)  and totaly enjoyed, this is my excuse for lack of my own workshop time
Fantastic work Chris,

Gary   

[crueby]

Another build thread I have wasted time following (64 pages)  and totaly enjoyed, this is my excuse for lack of my own workshop time
Fantastic work Chris,

Gary

Hi Gary,




I'll send you a copy of the plans, so you'll have to start building one!!     That way you won't have wasted any time reading up on it!

 

Chris

[crueby]

Yesterday the shop elves cleaned up the soldered valve body, and gave it a test fit...

So, today's word is HandWheel!  Turned up a blank for it, with a hub sticking out one side to hold on to (threaded to match the valve stem), and the sides both inset for the spokes. A hole was drilled/tapped in the rim for the handle after milling a flat spot.


Then went around and drilled starter holes for milling out the spaces between three spokes. Not a lot of measurements, just visually spaced out the first spoke around the handle hole, and turned the rotary table 120 degrees for each of the other spokes.

Then put in a mini end mill in the collet and milled the arcs between the spokes, taking the depth down in several steps since these little mills are not that strong for full depth cuts.

A couple of additional passes down the sides of the spokes and across the inner hub, followed by a little filing to clean up the edges, and the spokes were done.

Then turned up the handle on the lathe. The photo turned out too blurry to use, I didn't check the autofocus on it at the time so no shot of that. Up to your imagination!  Here it is installed:

and a test fit on the engine:

That was the last of the valves, so some great progress. Now for some more pipefitting - need to make the pipes/tees/elbows to connect the main valve to the starting valve next to it, and up to the bypass and main inlet pipe so that I can get some compressed air into the engine at last! That will allow me to finish up the centering/timing of the valves, and check the length of the valve spools too. They were made slightly long overall with the center narrow portions slightly short - wanted to have some room to fettle them to actual port sizes/positions if needed. Turning the engine over by hand and seeing which cylinder drain hole the air comes out of when will tell me what to do to the valve spool lengths, if anything. Once that is good, I can center up the travel by adjusting the position of the spools on the rod, then adjust the timing of each of the eccentrics. When all of that is done (lots of fiddly work!) and installing the drain valves the engine ought to actually run. Really looking forward to that! After the celebration, it will be back to finishing up the pipework, oilers, nameplate, paint touchup...

[cnr6400]

Looks like Bucket Bob on the right in the photo was checking out the sharpness of that finial. Good thing they were made by the Waytu-Sharpfer-Ryder Machine and Tool Co. 

Just kidding. Valve and handwheel look great!

[crueby]

Looks like Bucket Bob on the right in the photo was checking out the sharpness of that finial. Good thing they were made by the Waytu-Sharpfer-Ryder Machine and Tool Co. 

Just kidding. Valve and handwheel look great!

If the engine was runable yet I could have invented the Elf-A-Pult!   

[crueby]

More on the pipework, needed a Tee fitting larger than the cast ones I had, so pieced one up from brass rod. Turned the top of the tee, then chucked it up sideways to drill/bore a stepped hole partway through:

to take this inserted piece:

which was ready to be soldered in and drill the holes.

With the Tee ready (at the top above the valve in the next picture), started making up the other connecting pipes and a barbed tube fitting up top to connect to the compressor later. For display the barbed fitting will be unscrewed and removed. Here is the set of piping parts so far:

Still to make is the elbow connection below the starting valve on the left of that collection. Since both it and the main valve screw in, there will need to be an inline connection above the elbow, otherwise its one of those un-installable parts! Across the top to the left, there will be a pipe that wraps around the LP end of the engine, that is for the bypass to the exhaust/condensor (which I am not making). It has to be up high to clear the cylinder drain valves. This whole arrangement is set up to match the piping on the original engine. Also need to make up the pipes for the receiver drain underneath the LP cylinder, and the cylinder drain pipes...

[Baltic]

Well!
The valves look superb, and the hand wheel!! perfect Chris,

Gary 

[crueby]

Well!
The valves look superb, and the hand wheel!! perfect Chris,

Gary

Thanks Gary!  Got the connection from the starting valve made this morning, pics later. Almost ready to start applying compressed air and get the valves centered! Want to let the loctite cure up a day on the last connection, so will start timing tomorrow.