Calculate minimum starting stock for rectangular, round-bar and square-bar workpieces by adding machining allowance, facing allowance and optional saw kerf.
How do I calculate minimum raw stock size? Add the required machining allowance to the finished dimensions. If the allowance applies to both opposite sides, it is added twice.
What is a machining allowance? It is extra material intentionally left on the starting workpiece so machining can produce the required finished dimensions.
Should I add allowance to both sides? If your specified allowance is per side, yes. For example, a 2 mm allowance per side adds 4 mm to the overall dimension.
Does the calculator include saw kerf? Yes. An optional kerf can be added to the calculated raw length.
Can I calculate round-bar stock? Yes. Enter finished diameter and length plus diameter and end allowances.
Can I calculate square-bar stock? Yes. Enter the finished square side and length plus side and end allowances.
Does this calculator select commercial stock sizes? No. It calculates the minimum dimensional requirement. Actual purchasing should account for commercially available sizes and supplier tolerances.
How much machining allowance should I use? There is no universal value. It depends on material, stock condition, part size, process, tolerance, surface condition and the machining operation.