[TrentTroop]

Hey there. I do a lot of 3d printing work (I run the Prize Inside! Shapeways store, I can't link at the moment because I'm under my first 10 posts)

I'd be glad to help out.

The first think you want to do is get a pair of digital calipers if you don't have ones already. Once you have it you'll wonder how you got along without.

The rule is measure thrice, print as many times as needed to get it done. If you're using a home printer this is easy enough, if you're ordering from a service like shapeways I tend to recommend either mocking up a part that has the connection port with a number of slight variations on thickness/taper to figure out which one works before printing the connector attached to a larger and more expensive part. Or you can do the connector and main part in two pieces, so that if the connector comes back wrong you can just replace that, not the whole piece.

Typically, anything that pegs in should have a slight taper. For Transformers guns, for instance, the average peg-grip is 5mm in diameter, 8mm tall. For shapeways, in addition to beveling the peg at the end, I also make it so its 1% narrower at the end, and 1% wider at the base. This produces a good friction connection with the way Hasbro makes their 5mm ports/pegs in the Shapeways materials.

It's probable that the Megazord is going to use MM as its measurement of choice, so I recommend when you're doing your measurements to stick metric if at all possible.

Let me know if you have any questions.