I found myself in need to cut 1/2" mild steel plate today. The cut was about
4-3/4".
I tried first with my only reciprocating saw which is 18V cordless and a
Lenox 18 tpi blade (the only one I had on hand). The cut progressed very
slowly. I thought I would try my Bosch 1590 jig-saw not expecting much
(Bosch do not recommend use beyond 3/8") and I was not disappointed: It was
even worse. In the end I did most of the cut using a hacksaw with 18 tpi
blade (A DeWalt past its prime). This in fact was the fastest way and also
the cleanest (except for the mess that the lubricating wax makes :-).

I specifically avoided using a 4-1/2" cut-off wheel in my grinder: I find
those things very messy and hard to control. This policy was vindicated when
I tried to cut off a couple of the corners of the said plate. It was not
that fast either.

Oddly enough I find using the hacksaw less fatiguing than any of the other
tools: something about the better posture and rhythmic dynamic movement as
opposed to having to hold a vibrating tool still.

Although I do not expect to have to cut this sort of material in future very
often it got me thinking: Say one needed an even longer cut - 6" to 8". What
would be a good low cost ($200) alternative:
1) A corded recip saw with a 14 tpi blade - something like Milwaukee 6563-21
for $200
2) A portable band saw - no name off EBay for $110 including shipping. This
will cut only 4-1/2 by 4-1/2" so presumably the cut would have to be done
from two directions.
3) Put a abrasive disk in a circular saw with a decent motor and an all
metal construction (I could not do that today with my cordless as the guards
are plastic) - all for less than $100.

Thanks,

--
Michael Koblic,
Campbell River, BC