Posted by Willy-N [108.162.246.218] on Wednesday, October 04, 2017 at 22:27:50 :
In Reply to: Re: Piston Pin "Thumb Press Fit" posted by Vaughn [162.158.255.25] on Wednesday, October 04, 2017 at 22:14:12 :
I found this on the subject;
It is generally accepted that an oil film is .0005 thick, which is half a thousandth if I got my decimal places right. Since that film is on both sides of the piece it totals .001. The clearance for heat expansion is generally .002, which give a total clearance of .003. Any more than that is too loose so logically any less is too tight, but these are figures to keep in the back of your head only to be used if the machinist says something like, "It's good enough".