Posted by casebro on Monday, January 05, 2004 at 10:36AM :
In Reply to: Re: Anyone need speed parts for there PW posted by Dave Speed on Monday, January 05, 2004 at 8:37AM :
It's not so simple to make a pattern. You can't just copy the original, patterns have to be 3% oversize to allow for the shrinkege of the molten metal as it cools(3/8" per foot). The inner core pattern would be a mold itself, to make the sand core that makes the casting hollow. Everthing has to be within .030 so thickness won't vary by more than 1/16 throughout. And when the casting is done, it will need some machineing too....