Building the Trevithick Engine

[brian Rupnow]

Had a visit from three ghostly characters this afternoon. My grandchildren are all getting older. I'm glad they still come across town to Grandpa's house for a visit.

[brian Rupnow]

Not really a lot left on the "build" of this engine, but I still had to contend with the hole in the top of the boiler that the actuator arm for the 4 way valve (that I couldn't make work) stuck up through. I decided that the perfect answer to that hole would be a "steam dome". Steam domes are marvelous things. They can be anything that your fertile imagination wants them to be---a safety valve, a pressure indicator, a speedometer. Most living people under 60 years of age have never actually seen a steam engine. I've been fighting a mild flue all week so I think I'll spend the rest of the day on my couch with a good science fiction book.---Brian

[brian Rupnow]

Today I'm making wheels with cut-outs in the face. My approach is a bit different, but worth posting a shot of. I have to make four wheels that are identical in the cut out areas, bores, and outer diameters. I used a caliper and compass to lay out the diameter of the wheels on a sheet of 1/2" thick aluminum, cut out four rectangles, drilled and reamed on center and pushed a size on size rod thru the holes to keep everything centered, then ran bolts thru two opposing corners (which will become scrap), then stacked all four plates together in my machine vice to drill all of the holes in at once. That way I only have to do the set-up once. Next trick will be to separate all of the plates and cut the corners off, then turn to size in my lathe.

[brian Rupnow]

This shows the material that will be cut out of the four wheels. The material is 1/2" thick aluminum. Two of the wheels are only going to be 5/16" thick. The two wheels which have gears mounted on them will be 0.408" thick. My next step will be to cut off all of the outer corners and then turn the wheels to be round. Then I will grip them by the round outer rim with my 3 jaw lathe chuck and thin them down to finished thickness and open the center hole out to a finished diameter of 1/4". The windows will be cut out after the wheels are thinned down.

[brian Rupnow]

And we spent a goodly portion of the day on my lathe, making shiny wheels. The two wheels on the right which have raised bosses on the face are the ones which the gears attach to. The wheels are finished now except for cutting the windows in tomorrow on my mill and rotary table.

[brian Rupnow]

That went well!!! I still need to do a bit of hand filing, but very little. These four wheels are straight off the rotary table with no other work done on them. Putting in the windows was not difficult, but was time consuming.

[brian Rupnow]

I have reached the end. The engine runs very well, and is completely finished mechanically. I started this "design and build" on the last week of August, so it has been about a ten week job. My next step will be to paint the engine and then it goes up on the shelf with all of my other engines. Thank you very much to all of the people that had a look, and thank you for the comments that were made as I progressed with the build. I hope you enjoyed it.---Brian
https://www.youtube.com/watch?v=mSDcE8Jfn2g

[woodenbird]

Thanks for taking us along for the ride. It has been a very enjoyable watch. Fine job!

[Hawkeye]

Great build! Thanks for sharing!

[olf20]

Great job! I again learned more processes to use in doing my little fun projects. You are quite talented.

[Cuttings]

Very good job Brian. Your persistence payed off.

[brian Rupnow]

A stinky business!!!--Wish I could have done this painting a month ago when it was warmer outside. As things set, I open my big garage door, set out all the stuff to be spray painted, paint it, then move everything into my machine shop so it will dry enough for a second coat. This comes out to four trips into and out of the garage (2 coats on each side). My house smells like a body and paint shop. I am fortunate to have a very understanding wife!!!

[aostling]

Did you run out of drop cloths to cover the vice grips?

[RB211]

Painting and finishing is my least favorite thing to do, but accounts for 90% of the Oooh's and Ahhh's of an item.

[brian Rupnow]

No, I didn't run out of drop cloths to cover the vice grips. Over the years the vice grips do take on some interesting colors.