How do you calculate regrind yield?

Divide the rejected tool count by the total tools in the batch to get the reject rate. With 8 rejects out of 250 tools, the reject rate is 3.2%, meaning about 96.8% of the batch was salvaged.

What is a good regrind yield for a sharpening shop?

Salvage rates above 95% are healthy for tools screened at intake, so a reject rate under 5% is the common target. The 3.2% reject in this example is solid; a climbing reject rate points to intake screening or wheel and process problems.

What does the gap to target mean here?

The gap is your target rate minus the calculated rate in points. With a 95% reference target and a 3.2% calculated reject rate, the tool reports a 91.8-point gap, which is a raw arithmetic gap; interpret it against whether your target is a salvage target or a max-reject ceiling.

Why is my regrind reject rate rising?

Common causes are worn or wrong grinding wheels, too-aggressive stock removal that runs tools under minimum length, dull tools arriving past salvage, and weak incoming inspection. Isolate by tracking reject reason codes alongside this rate.

Regrind yield vs first-pass yield, are they the same?

No. First-pass yield counts tools that pass the first time without rework; regrind yield here is the salvage-versus-scrap split for the reconditioning batch. A tool can need a second grind pass yet still be salvaged and counted as good yield.

Should intake inspection reject count toward this rate?

Decide once and stay consistent. Many shops track two numbers: tools scrapped at intake and tools scrapped after grinding. Combining them hides whether your screen or your process is the problem.

Tool Sharpening, Reconditioning & Industrial Repair Services calculator

Regrind Yield Calculator

Regrind yield tells a reconditioning shop what fraction of an inbound tool batch could not be salvaged, so it is the scrap side of your salvage performance. Grinding supervisors and quality leads watch it to catch tools coming in too worn, chipped, or short to bring back to spec. It matters because every scrapped tool is a customer that either buys new or blames the shop, and a creeping reject rate signals worn wheels, aggressive stock removal, or an intake screen that lets dead tools through. This calculator turns a reject count into a yield-loss percentage and shows the gap to your salvage target.

What this calculator does

Regrind yield tells a reconditioning shop what fraction of an inbound tool batch could not be salvaged, so it is the scrap side of your salvage performance.
Use it when regrind yield in tool sharpening, reconditioning and industrial repair services needs a clean rate and gap-to-target you can put on a tier board.
It computes the reject or scrap rate as rejected tools divided by total tools, then the point gap between that rate and your target salvage rate.

Formula used

Regrind Yield rate = affected amount ÷ total amount
Gap to target = target rate - calculated rate

Inputs explained

Tools scrapped or rejected after regrind:
Tools entering the regrind batch:
Target salvage rate:

How to use the result

Use it after finishing a regrind batch to score salvage performance, or during intake to test whether a worn incoming lot is worth accepting.
It treats every rejected tool the same; it does not weigh a scrapped carbide hob against a cheap HSS drill, so pair it with a cost view before acting on the percentage.

Common questions

How do you calculate regrind yield? Divide the rejected tool count by the total tools in the batch to get the reject rate. With 8 rejects out of 250 tools, the reject rate is 3.2%, meaning about 96.8% of the batch was salvaged.
What is a good regrind yield for a sharpening shop? Salvage rates above 95% are healthy for tools screened at intake, so a reject rate under 5% is the common target. The 3.2% reject in this example is solid; a climbing reject rate points to intake screening or wheel and process problems.
What does the gap to target mean here? The gap is your target rate minus the calculated rate in points. With a 95% reference target and a 3.2% calculated reject rate, the tool reports a 91.8-point gap, which is a raw arithmetic gap; interpret it against whether your target is a salvage target or a max-reject ceiling.
Why is my regrind reject rate rising? Common causes are worn or wrong grinding wheels, too-aggressive stock removal that runs tools under minimum length, dull tools arriving past salvage, and weak incoming inspection. Isolate by tracking reject reason codes alongside this rate.
Regrind yield vs first-pass yield, are they the same? No. First-pass yield counts tools that pass the first time without rework; regrind yield here is the salvage-versus-scrap split for the reconditioning batch. A tool can need a second grind pass yet still be salvaged and counted as good yield.

Last reviewed 2026-05-12.