this is what i used to do when i was on the floor;
with the core cut, i'd messure the perallels (rails) and stop buttons, and figure out my packing (between the ejector plates and core). I'd then put the ejector plates on the back of core with packing (123 blocks and shims +.050 to be safe). after securing the plate on with couple of clamps and return pins i'd flip it on it's side and add the rest of the pins. Go to the front of the mold and push the pin back till they are flush with the molding face, then go to the back and scale how much the pin is sticking out past the plate......chop it off on a saw.... Later on i'd assamble the core, put the Jackscrews in (and pull back screws) to make sure the plates are back, and then i'd grind the pins flush with a disk.....or give it to my polishing guy to blend the pins....lot of times he has to get a head start on polishing anyways.......on a medium size mold it can be all done in a day.
as for venting, i make a setup on a surface grinder and grind .001 for about 3" down, on 3 places around the pin. once you set the height, no need to change it, just place the pin and move the table once and it's done.....
all our pins are D-locked. we usually rough out the flat on a bench grinder and then make a setup on a surace grinder to finish it......make one stup....eyeball the flat horizontal.....bring in the wheel and grind it (almost tangent to pin dia.).....DONE!!!!
plates holes and pockets are done CNC, with .031 clearence in the holes in plates (makes the ejection go easyer....ejector guides keep it going straight....if the pins are reamed in plates SOMETIMES they fight eachother)
as for miking the holes....never done it....
I send my ejection to be "gundrilled" and it's usually close enough....sometimes i trow a reamer in the hole by hand just take the burs off if there are any....Cheeper then doing it in house.  |