Sacrificial block

[7HC]

I've done that very thing several times, aluminum works great, but watch that it doesn't gum up on you.
Larry

In that case, would it be better to use the aluminum spacer up to just before and just after the point of milling, leaving a gap where the endmill will penetrate?


M

 

[wawoodman]

Thanks for all the suggestions. I looked at my 3/4" cutter again, and realized it was a four-flute, not center cutting. So I wound up doing them individually, and coming in from the side. Worked fine (for certain definitions of "fine.")

 

[Hawkeye]

If you take a good look at the picture in the link, you'll see that both pieces are cut at the same time. One arm just happens to be longer than the other. The reason for doing them at the same time is that the arms are registered at the other end. I wanted the grooves to be the same distance from the pivot points.

The spacer isn't sacrificial in this case. It is clamped between the arms in the vise. The plunge milling is being done just outside of the jaws. Having a space between the arms prevents the aluminum from gumming up and allows the steel swarf to escape.

It actually worked quite well. Work pieces that aren't as stiff as those ones were would be better done with a sacrificial spacer.