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Cutting Parameters

Tool Runout & Chip Thickness Calculator

Tool runout causes uneven chip loading on multi-flute cutters. One flute takes a thicker chip while the opposite flute takes a thinner one, accelerating wear on the overloaded...

Input Parameters

Results

Average Chip Thickness (mm)
Max Chip Thickness (mm)
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Runout and chip thickness formula

Tool runout causes uneven chip loading on multi-flute cutters. One flute takes a thicker chip while the opposite flute takes a thinner one, accelerating wear on the overloaded edge.

Frequently asked questions

What is acceptable tool runout?

For carbide end mills under 12 mm, aim for runout below 10 µm TIR. Over 20 µm significantly shortens tool life and degrades surface finish. High-precision hydraulic or shrink-fit holders typically achieve under 5 µm.

How does runout affect tool life?

With 10 µm runout, the heaviest-loaded tooth can see 20% higher chip thickness than average. This disproportionate load can reduce tool life by 30-50% compared to a perfectly centred tool.

Can I measure runout without a dial indicator?

No. You need a dial test indicator (0.001 mm resolution) mounted on a magnetic base. Measure TIR on the tool shank near the holder, then at the tool tip to separate holder error from tool error.

How to use this Tool Runout & Chip Thickness Calculator

Measure the total indicator reading (TIR) at the tool tip with a dial indicator. Enter that runout value in microns and your programmed feed per tooth. The calculator shows average and maximum chip thickness to help you determine if runout is within acceptable limits.

Common mistakes to avoid

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