1/16 scale 1916 Case 65 HP Steam Traction Engine

[internal_fire]

I have spent a lot of time studying plans for the Case 65, and I think I now understand the clutch mechanism.

Your version is very, very close to the original. Yes, there is a collar to separate the over-center parts from the pinion.

Here is a sketch that shows the basics.

Gene

[raveney]

 A few more parts this week for the case 65 HP,
First crankshaft flywheel was too small, second one looks better. I measure the pictures and do a ratio comparing to the wheels or boiler shell (known diameters)
Made a crosshead cylinder and support that will sandwich between crosshead and cylinder head. It will also support the maintenance shelf and steps.
The crosshead on Rudy's plan is much simpler, but this one was used by Kim on his build and looks much more representative to the real one. I would have liked to use more studs/bolts than the four, but it appeared that they would interfere with the steam passages and exhaust port.

[Kim]

The larger flywheel and crosshead look great! Much better proportioned to the substantial machine that this truly is! 

Kim 

[Roger B]

Excellent    I like the way you are calculating the forces in the clutch mechanism 

[Zephyrin]

the clutch mechanism is very clever and works perfectly, well done.
does the hexagonal part for adjustment have left and right handed threads?

[raveney]

Thank you for the compliments and comments,
 
this project is a lot of fun as I am able to deviate from plans often and there is a lot of reference materials online.

I assume that the hex should have both left and right hand threads, but I omitted them as I don't have the LH dies or taps for 2-56 thread. I'm not sure they even make left hand taps this small?

I still thought hex threaded couplings were needed. Adjustability was necessary to ensure equal lengths, and I set that using two drill bits through the clevise ends of both rods. Then I secured them using green loctite. The shoe friction is then adjusted by how far the flywheel is pushed onto the shaft.

For now I have tiny strips of work glove leather attached on the shoes using contact cement. Should last a while?

[raveney]

image to better show what was meant about hex couplings and adjustment of clutch

[Krypto]

You are doing some great work here!  It will be interesting to see how the clutch works under a load.

PM models has LH tap & dies at 0-80 & 1-72 if you feel the need (also found LH 2-56 at various other places).

The leather should hold up well.  Back in the day, I used to race nitro-powered RC sprint cars and my car was using an aftermarket brake system that was basically a brass strip with bonded leather wrapped around an aluminum drum.  The leather held-up well for several seasons in a much harder use case so in your engine it should last practically forever.

[raveney]

Thank you Krypto,
A few more weekends and I might be able to test it on air.
Continued work on the steam engine parts. Mainly using Rudy's excellent book but made dimensional adjustments to make the modified crosshead and flywheel work out.
I used a bit of 304 SS for the piston rod, and thought I was going to have a fit threading it, but it went fine. Used bronze offcuts for the piston and valve. Still need to make one more gland nut and I can put it together for keeps.

[crueby]

Great looking parts!       Following along here. 

I also tried some 304 stainless on a recent project, never again! It work hardens really quickly.