Just recently, I read an article describing, and showing a method for making model engine pistons with crowns consisting of two or more pieces, stacked, in the crown area for easy, distortion-free ring installation. I cannot find the article, nor the photos. I don't even know where to begin to look. A search led me to no results.
The conventional-looking piston(s) had a modified and removable crown section which was made up of stacked, discs (piston material), some having a smaller diameter, some having full-bore diameter (plus clearances). Conventional, cast-iron rings with correct clearances, end-gap etc. were made, and became part of the stacked assembly, so the piston crown, once installed, captured the ring(s). The piston rings were never distorted for installation, but simply slipped onto the outside of the smaller diameter discs, and capped with a larger disc, or the final, crown section.
CCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCC
RR DDDDDDDDDDDDD RR
DDDDDDDDDDDDDDDDDD
RR DDDDDDDDDDDDD RR
PPPPPPPPPPPPPPPPPPPP
PPPPPPPPPPPPPPPPPPPP
PPPPPPPPPPPPPPPPPPPP
PPPPPPPPPPPPPPPPPPPP
PPPPPPPPPPPPPPPPPPPP
PPPPPPPPPPPPPPPPPPPP
PPPPPPPPPPPPPPPPPPPP
C= crown section
R= rings
D= stacked disk
P= Piston skirt
Anyone use this method? I would like to re-read the article....where do I find this information? I hope the above diagram reproduces as I have originally drawn it. It should all be the same diameter...and represent a stacked piston with captured rings.
Frank