1/3-rd scale Myrick Model H vertical hot tube engine

[myrickman]

Here is the beginnings of a project to make a one-third scale model of a Myrick Model H engine circa 1912 from Olean, NY. I saw this model in finished form at Coolspring Power Museum a few years ago. The fellow who made it intended it to be a one-off. It was made from aluminum castings. This one will be all cast iron. The patterns for the engine then went to another friend who had plans to put it on pattern boards but alas, he ended up returning them to the original owner. The original owner sent them to me and here we are. I have a copy of the orginal blueprint for this engine so it will make sizing the piston, gears and con rod much easier. The enlargement of the drawing I made just happened to be exactly the same size as the model patterns- how is that for luck? Flywheels are 11" and quite beefy so with a 2" bore and 2.5" stroke, it should thump pretty good for a model. My plans are to replicate the earlier model H with the "lollypop" governer instead of the usual 2-weight system found on many other models. Con rod will be bronze. A few artistic liberties were taken with the fins; fewer than on the original engine. Will try to run it on a hot tube and propane. Pictures of the project will be posted to my picasa album at:
https://picasaweb.google.com/113212157040763340674/MyrickModelHModel
Check back every few weeks. Today I finished the piston pattern.

 

[willburrrr2003]

Looking good!!! I love to see casting projects please post pics of the pours and when you take the parts out of the sand!

Good luck, and best wishing on your project!

Will R

 

[JorgensenSteam]

Nice patterns and engine.

 

[myrickman]

Couple of new pix on the link the original post. Working on a useable hot tube which will scale down. Took some time fooling around with fuel pressure and air vents to get the heat right. Next thing when the engine is done is to try various lengths to get the timing right.

 

[myrickman]

I posted a couple of pictures of the castings from the foundry to the picasa album at the top of the thread. I was pleased with the way they came out. The finished model will weigh in at about 60-70 pounds. This is going to be a team build of sorts with two friends of mine over the winter.

 

[myrickman]

I got back on this build today and should be working on it hard throughout December. This weekend was spent machining the base and bearing caps. The plan is to pour Babbitt bearings with a 1 inch OD and 3/4 inch ID. If you go to the link to the Picasa album in an earlier post, there are many more pix.

 

[idahoan]

Great stuff Myrickman

Thanks for the the tip on the Picasa link: I enjoyed looking at your progress and setups.

Dave

 

[myrickman]

Used in the oil and gas fields in the NY/PA area. Stands about 4 feet tall.

 

[myrickman]

Made some more progress on the model over last few days. Got the flywheel rims and hubs finished. The keys will be 3/16" gibs. Crankshaft diameter 3/4". If you go to the link at the top of the thread you can see how I did the bores. Then they were dogged to a piece of 3/4" drill rod on the lathe for cleanup. One flywheel has the inner and outer hubs machined to accept a sleeve for the governer and the outer one to clear the lollipop which rotates the sleeve which moves in and out against two spirals lots in the sleeve. The head and intake chest was begun today. Since this a natural gas engine, a hole in the intake valve seat supplies the gas to the engine. The head cleanup was straightforward, but making the passage from the combustion chamber to the valves took a lot of setup. The passage is at a 35 degree angle so I had to mount it to a tilt table which was bolted to an angle plate. I'll cut the passage in two days when I get back to it. I included a picture of the mocked up engine to give you an idea of what it will look like. Have to order a 16DP 20 and 40 tooth gear set for the cam drive.

 

[vcutajar]

Following your progress as you move along the build.

Vince

 

[Brian Rupnow]

Very impressive build. You seem to know what you are doing, and I mean that as a compliment.---Brian

 

[myrickman]

Thanks Brian and others for the kind words of encouragement. There are so many great builds documented on this site. I have learned a lot of shop tricks from them. Seeing others' projects is very inspirational and helps keep the momentum going.

 

[myrickman]

I uploaded 9 more pix of the Myrick build to the Picasa site. See the top of the thread for the link. This time, there are pix of the rotary table being used to machine the arch piece which supports the cylinder. Also detailed is the setup used to cut the passage between the combustion chamber and the valve chest.

 

[myrickman]

Added some more pictures of the build to Picasa link at top of thread. The bore was honed in to 2.000 on a Sunnen hone by a good friend of mine. Machined the piston od and cut the ring grooves for two 3/32 rings. Next was to finish up the intake valve assembly. The valve seat needs to be wide enough to seal 2 0.050" holes which deliver gas during the intake stroke. Valves were made from drill rod in two pieces. The governer assembly was begun. The lollipop on the outside of the flywheel pivots against a shaft. On the inside of the flywheel, a dog rotates a sleeve. 2 helical slots in the sleeve (not done yet) move the collar in and out to move the latch arm against the exhaust valve to achieve hit and miss governing.

 

[myrickman]

Worked on the pivot point for the governer latch lever. I hogged it out a piece of 1 inch round stock and soldered on the ear which holds a spring to push the lever out away from the latch block. Shown is the full scale gear which is about 6 inches across and the scaled gear. I did not put the radii on the vertical tabs until I make the lever and drill the holes for the retaining pin. The scaled gear will get a dishing on the front face like the full scale and to remove the china embossing.

 

[myrickman]

Made the stand for the model from 50+ year old tongue and groove mahogany. It will get two rows of brass screws where the decking joins the runners. Usually I make this last but had the wood shop fired up on another project.

 

[myrickman]

Made up the crankshaft over last two days. The web holes were 0.001 undersized. I heated the webs to about 1100F and slid them into place. A one inch gage block kept the spacing correct. The journal pin was press fit. Cross pins were also press fit through the rods and the webs. All pin ends were TIG welded to fuse the pins to the webs. When it was all finished, there was a slight spring of the webs together. A quick bump on the arbor press brought the assembly back to running true. If you go to the picasa link at post beginning, more detail is shown. For some reason I can only attach one photo at a time from my iPad. Here is shown the crank after the first welding was done and the center cut away.

 

[myrickman]

Spent most of the day finishing the governer sleeve actuation. A spring-loaded weight and arm on the outside of the flywheel rotates a shaft through the flywheel spoke and drives a dog or finger which rotates the bronze sleeve a few degrees. Two spiral slots in the sleeve and two pins in the flywheel hub cause the sleeve to move in and out parallel to the crankshaft axis. To layout the 35 degree slots, I made a sleeve to go over the bronze governer collar where I machined a large slot where one side passed through the layout sleeve center. Then I scribed one side of the slot in the bronze sleeve, rotated the outer sleeve, and scribed the other side of the spiral slot.

 

[myrickman]

Once the slots were laid out, the sleeve was placed in the mill and the right side of it against a stop. The cutter was centered on the sleeve axis (x direction) and the y axis was eyeballed to be within the center of the layout lines. Through 7-8 rotation steps, y-axis adjustments and plunges, the spiral slot was developed. Afterwards, a small flat file was used to dress down the ridges leaving a smooth slot. The sleeve was rotated 180 degrees and the slot profile repeated. More detail is on the Picasa link at the thread beginning.

 

[myrickman]

Here is what the finished assembly looks like. It works freely and the sleeve moves in and out about 3/32"; plenty to move the latch lever and hold the exhaust valve open.