Home Workspace | New Stock and Milling Advice

While I was out today, I also stopped by a local machine shop to discuss better ways of milling out small parts, primarily the pendant that I worked on a couple of weeks ago. 

He suggested that instead of having the two pegs for the part to stand on, it would have better rigidity to have a thin flap of metal surrounding the piece. It would also help with cutting the pendant loose; for my system, I would simultaneously cut off the part and finish the face, which was quite difficult and left a bunch of imperfections I couldn't remove later. He also suggested using putty to fill in the first side milled out; this would prevent vibrations, which could cause a bad surface finish. You can see in the images of how he milled out similar parts.

In addition to all this, he mentioned that it would be easier to get the side's filleted with a square endmill vs. a ball endmill. The reasoning behind this was you would need the ball endmill to reach farther down past the part and would interrupt the metal flap around the piece. I initially thought he meant to do step-downs with the square endmill, which would leave steps on the finished part, but rather mill it to flow over the sides.

Another great piece of advice he gave me was for the tooling itself. He was saying that you only want as much flute length as you're going to use, and any more than that would be pointless and give you less tool rigidity. I've heard this from Saunders and a few other people as well but forgot it when ordering the new endmills. He also gave me a Harvey tool catalog which he said would explain the purposes behind coating and the best endmills for the material being used.

After giving me this very much needed advice, he gave me a bunch of new stock I could use to mill. Mostly 6061 aluminum but also a bar of 7071, and aluminum & bronze compound, some more acrylic, and black material that I forget the name of but reminds me of micarta.