Cut Doctor
Bad cut? We'll tell you why.
Melting, chipping, burning or tearout — tell us what you ran, or upload a photo of the edge, and you'll get the cause, the corrected numbers, and the bit that does the job properly.
Free — no signup, no login
Built on Onsrud & Amana published data
Reads a photo of your cut
1,100+ bits with published data
1 · Material2 · Your bit3 · The problem4 · Your settingsDiagnosis
Diagnosis is computed from manufacturer chipload data across 1,100+ spec'd bits. Need a bit instead? Use the Bit Finder — or dial in a known bit with the Feed Rate Calculator.
Where these numbers come from
- Chipload targets are taken from published manufacturer engineering charts — the LMT Onsrud 2023 catalog (per-series chip loads by cutting diameter), LMT Onsrud's 2020 Aluminum Cutting Data, and Amana Tool's official speed charts (compression spiral, mortise compression, carbide-tipped straight plunge, plastic and aluminum O-flute, ball nose and V-groove series). Over 1,100 bits in our catalogue carry their manufacturer's own chipload table, and every stored value cites the exact source document it came from.
- Where manufacturers disagree, we say so instead of averaging it away. Amana publishes deliberately more conservative chip loads than Onsrud for the same geometry — both are correct by their own testing, and a recommendation tied to a specific bit follows that maker's numbers.
- Baseline ranges assume a 1/4″ two-flute tool at 1×D depth of cut. Below 3/16″ we scale chiploads down to match Onsrud's own published small-diameter ratios. Manufacturer convention for depth: full chip load at 1×D, reduce ~25% at 2×D, ~50% at 3×D.
- Your machine bounds every suggestion. Save your spindle's max/min RPM, max feed rate and rigidity class, and recommendations are capped to what your machine can actually execute — a light gantry gets depth-of-cut guidance instead of feed rates it can't hold.
- What no calculator can know: your machine's real rigidity under load, workholding, spindle runout, and tool wear. That's why chatter advice here starts with stickout and collet condition, not feed math — and why we ask “Did this fix your cut?” after every diagnosis. Those answers, along with reorder intervals measured from our own order history, feed back into the tool.
