I've just spent a few minutes thinking about the rooster tail of sparks
that would be flying into my saw, and out of that little DC outlet, and
all the plastic parts that saw's got, and I've come to the conclusion
that I'm not going to think about it any more. I'm sure it would work
but I don't want to experiment with how the saw reacts to it. :-)

Seems like you could cut those pieces with a hacksaw, your tablesaw, or
a used bandsaw like Dave says, and then set up a jig for a grinder or
sander so you could fine-tune the angle to 45. That's what I'd think
about.

No actually I'd think about taking them out to a friend who's got all
kinds of metalworking tools but if he wasn't around I'd think about it.