John, Don't worry about making cores for those steam ports for therein lies madness. Make a core for the cylinder bore and let it go at that. I have cast cylinders for my 2-1/2" scale Mich-Cal Shay using a core for the bore and then milled and drilled the steam ports. Worked out just fine and it will for you also. Jesse the Redneck in Tennessee does anyone think that it is worth doing small cores for the ports, I would think i could get in by machining them and that would make the casting easier. yours for now John Burridge This email was cleaned by emailStripper, available for free from http://www.papercut.biz/emailStripper.htm MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.