Page 69 - Issue 45

Metal break:
» This is a large tool used
to cleanly bend sheet metal
in an accurate & consistent
fashion. I have a Roper
Whitney 18 gauge 48” break
that I used quite often.
There are charts

& calculators for
bend allowances.

» Bend allowances: Bend allowances are
the amount of “stretch” that occurs in your
material as a result of bending. For example,
if you have a piece that needs to be precisely
10” wide and have two 10” “legs” (in an L
shape with a single 90 degree corner) you will
actually need to cut your material a little bit
on the short side to account for the material
it will gain through stretching around the
90* bend. Each bend adds to the amount of
overall material you will add to your fi nished
size. There are charts & calculators for bend
allowances. It also depends how you are bending
the steel (radius size) and the hardness of the steel,
etc. A rule of thumb I generally use is to add .100”
additional per 90 degree bend on a piece of 18
gauge with a standard (small) brake’s radius. So
with the single 90* bend, your piece would need to
start as a 19.9”x10” piece.

RATRODMAGAZINE.COM RAT ROD MAGAZINE 69

68x71tinman.indd 69 8/1/17 9:37 PM