Question 1

Why does actual metal weight differ from calculated weight?

Accepted Answer

Calculated weight uses nominal dimensions and standard density. Actual weight varies due to rolling tolerances (typically ±2.5% for hot-rolled products per ASTM A6), alloy composition differences within specification ranges, and surface conditions. For critical applications, always weigh the actual material.

Question 2

How do I account for material removed by machining?

Accepted Answer

Calculate the weight of the raw stock, then subtract the weight of material removed. For complex shapes, calculate the finished part volume from your CAD model. As a rule of thumb, machined parts from bar stock may lose 30-60% of the original material weight depending on the geometry.