Answer:
0.006174 in
Step-by-step explanation:
The thermal expansion coefficients I found were ...
5.8×10^-6/°F for gray cast iron
7.2×10^-6/°F for structural steel
Then the difference in expansion dimensions for a 42-inch length will be ...
(42 in)((7.2 -5.8)×10^-6/°F)(165 -60)°F = (42 in)(1.4×10^-6)(105) = 0.006174 in
The difference in thermal expansion over that temperature range will be about 0.006174 inches.