I purchased a older,used Rockwell 10" Unisaw. The motor is a 3HP/220v. I recently noticed that the blade is flush with the top of the table when the blade is all the way down. I am not sure if this condition existed when I originally set the saw up. I'm trying to figure out how to get the blade to lower further because I can't put in a new zero clearance insert with the blade as high as it is now. The blade mechanism is raised and lowered by a screw gear moving a circular gear and the screw gear is locked to a shaft by a roll pin.