Necessity of hardened crank pins on 3/4” scale

[matthew-s]

for that it is worth, I use 1144 (stress proof) for all my axles and pins.
I do not harden pins. so far this has not been any issues with wear. but i also run propane fired locomotives so i do not have any issues with coal dust etc.

I’m so far away from the boiler, it’s not even funny. That said, I would seriously consider building for a gas-fired burner when I get to that point.

It’s not clear to me whether that actually works out on these small scale (3/4”) models, especially when it comes to having a place for the fuel, not having icing issues, etc.

[matthew-s]

To close the loop on this:

I successfully machined all 4 crank pins out of 1144 “ultra-strength” steel. Advertised at Rockwell 30c.

The material was pretty easy to machine. I was able to hold the tight tolerances in the drawing, with my micro mark 7x16 lathe. Although I hit most of the final dimensions using Emory paper.

Truth be told it machines so well, I sort of wonder If it is REALLY Rockwell 30c! Material was from McMaster so I have no reason to doubt it.

So, check back in about 18 years* to see if I was able to get away with 1144 over hardened pins!

Thanks for the help, I would not have gone this way on my own.

* 8 more years to build, 10 to run in for wear!