Many ingot molds however make 3.5 mm ingots. If your mills max thickness
is 3.0, the best thing to do is to grind down the sides of the ingot mold
so that it makes an ingot of 3.0mm or less.
One other way to decrease the size of the billet that’s not as wasteful of
material as grinding, is forging. The billet is relatively soft in it’s
normal state after cooling. Place the billet on an anvil or solid steel
surface that’s well supported. Use a heavy (2-3 lb.) hammer with the wide,
flat face to forge the billet thin enough to go through the mill. Work the
billet evenly to leave the surface as un-dimpled as possible. If there’s a
thick (3/4 in. or greater) piece of flat steel available, it could be
placed on top of the billet & the hammer applied to that. Depending on the
reduction necessary, the billet may have to be annealed after forging &
If more billets will be made for rolling in the future, the mold used to
make them should be marked with a depth indicator indicating the height to
which billets intended for rolling are poured.
Determine the depth (D) of your mold at the deepest spot. Subtract the
mill roll opening distance (O) from this number. The result is the distance
from the top (T) of the mold a mark should be placed. The formula is D - O
When making the roll opening measurement, be sure the teeth stay meshed
for the entire circumference of both gears. How much the gears need to be
meshed depends on the contour of the gear tips. If the gears do not mesh
sufficiently, they’ll wear more at the tips & have a tendency to try to
climb over one another. If they climb over one another there’s every
probability of serious damage to some part of the mill.
Use a scribe or cut off blade to incise a mark along the inside of the
mold for the full length at a distance ‘T’ down from the top of the mold.
The line only needs to be deep enough to be easily seen while pour billets
for rolling. When pouring billets that will be rolled, stop pouring when
the line has been reached. The line won’t interfere with casting billets
that are thicker than rolling billets.