Tools / Stock
Stock and Weight Calculator
You are buying the block, not the part. This works out how much of it you are paying to turn into chips.
Stock block, mm
Finished part
Stock weight1.166 kg
Finished weight0.324 kg
Removed72 %
What to do with the number
A high removal percentage tells you two things. The alloy premium lands on the whole block, so switching from 6061 to 7075 on a part that is 85% swarf is an expensive decision. And the roughing time is a large share of the cycle, so anything that lets the shop take heavier cuts pays back.
- Drop to the next stock sizeA part drawn 52 mm thick forces 60 mm plate. Drawn at 50 mm it may need no facing at all.
- Open the internal corner radiiA 3 mm corner lets the shop use a bigger, stiffer cutter than a 1 mm corner does. Same part, far less time.
- Say what is negotiableMarking a dimension as free to move to the next standard size regularly takes double digits off a quote.
Questions
Why does the stock block matter more than the finished part?
Because you pay for the metal that arrives, not the metal that leaves. A part that would clear 60 mm plate but is drawn from 80 mm carries the extra material cost and the extra machine time spent turning that material into swarf.
What is a normal buy-to-fly ratio?
It varies enormously. A plate bracket might remove 40% of the block. A pocketed housing routinely removes 80% or more, and aerospace structure can exceed 90%. The number itself is less useful than what it tells you: the higher it is, the more the alloy price and the roughing time dominate your quote.
Does this calculate my part price?
No, and be wary of any tool that claims to. Material is only one input, alongside setups, cycle time, tolerance, inspection and finishing. This shows you how much of the quote is being driven by metal you are paying to remove.