Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I was having a problem with the mason. made progress yesterday on my 1901 model C mason, I was able to remove the piston from the cylinder. The problem was that I could not unscrew the connecting rod from the crosshead. I loosened the piston rod assembly nut, but it would not unscrew. After a very close look, I found a pin going thru the crosshead rod. I drove the pinout and then was able to unscrew it. My question is why to use a pin when you have a locking nut. My last mason 1899 did not have this pin just a locking nut.