When you cut a strip with shears, the shears will push the metal
ahead of the cut, essentially stretching that edge of the strip a
bit so the strip curves away. I don’t know how wide or thick your
strips are but obviously the narrower and thinner they are, the less
they will be able to resist that push.
If you could stretch the opposite edge of the strip equally then it
might counter and cancel out the stretch you have imposed on the cut
edge. So how about this? Cut your strips twice as wide as needed.
Then re-cut the double-wide strip down the centre into two of
desired width. That way each strip will have been stretched along
each of its edges. Probably won’t produce perfect straightness but
might get the strips closer to straight by balancing the stresses.
This may work - I haven’t tried it myself yet. I prefer to work from
my armchair this morning.
Marty - on the straight and narrow in Victoria.