On Thu, 1 Oct 2020 22:33:59 +0100, Graeme
wrote:

snip

Thanks chaps. Yes, I do have a fairly old but reliable B&D jigsaw, and
a selection of blades, almost certainly including a metal cutting blade.

You might need 'blades', depending ... ;-)

That is now Plan A, but at slow cutting speed?

There are formulae for the right speed for cutting all sorts of
materials, with and without lube and so to answer that we may need to
know the thickness of the steel and the pitch of the blade (which I
think ideally needs to be 'matched' (or within certain criteria)).

https://en.wikipedia.org/wiki/Speeds...#Cutting_speed

https://www.bosch-professional.com/p...592774-ocs-ac/

https://www.wonkeedonkeetools.co.uk/...ed-of-a-jigsaw

Will fast just take the
teeth off the blade in short order?

If the cutting action heats the blade too much, potentially 'yes' but
again, how / when / if that happens depends on the above, the quality
of the blade and how hard you push it?

If you have a variable speed jobby then you can often get a feel of
what seems to work best (for fast it goes though the material) and at
what points (fast / slow) it seems like nothing is happening.

The other thing is if you have a rake(?) control, the blade going
forward, up, back, down or not. Sometimes adjusting that (probably
none or 1 on thin steel, depending on the quality of the blade etc
etc) and again, it will often tell you what's right (or not if it
grabs) by how 'nicely' it cuts.

And that often = the fastest cut with the least effort from you and
with no grabbing.

I was wondering, if you cut it off a bit from the top, if you could
make a support / base with the top? Cut some legs / holes in it to let
the heat out / air in (if you have holes in the bottom) and wire it to
the main part with some coat hanger?

Cheers, T i m