Originally Posted by
RCaffin
I am not sure I fully understand what you are asking, but let's try.
If you need to mill both top and bottom of a part, you will need to flip it over. For this to be done successfully, there are a few things you need to look after.
1) Sacrificial base plate must be used, and it must be skimmed flat and horizontal.
2) Use pins, NOT screws, to locate the part in both positions. Screws are too sloppy. The holes for the pins in both the base plate and the object need to be a nice fit.
3) In theory 2 pins are enough; in practice you should use at least 4. And they should be as far apart as possible.
4) The pins must come in pairs, oriented on-axis. That is, both pins in a pair must have the same Y position (or X, it you want to flip that way).
5) The pins LOCATE: you will also need clamps to hold down.
I use pins of 2.4 mm diameter: either short bit of 2.4 mm Ti welding wire or the shanks of 2.4 mm drill bits. The holes are also 2.4 mm, NOT 2.5 mm. That does mean some tight fits, which is intentional. But you could use any diameter you want.
Then you program accordingly, assuming a straight mirror.
Cheers
Roger