Methodology

The ranking score

Every machine is scored 0–100. Components are scored against absolute reference scales rather than percentiles within our current database, which means a machine's score does not change when an unrelated machine is added, and you can reproduce any score from the spec sheet plus these weights.

Reference scales

How we handle a specification a maker does not publish

This is the most consequential decision in the model, so it is worth stating plainly. When a manufacturer does not publish a figure - the FoxAlien XE-Ultra ships without a spindle, so it has no spindle wattage at all; SainSmart states a stepper model for the 4040-PRO MAX but never says whether it is closed-loop - we exclude that component and renormalise across the weights we could actually apply. We do not score it zero. Scoring an unpublished spec as zero would punish a machine for a fact we simply do not know.

Renormalising on its own has a flaw we are not willing to live with. A maker who publishes only their machine's strongest figures gets scored on just those figures, and rescaling that partial result can lift it above a competitor who published everything. That rewards withholding - on a site whose entire argument is that withholding should count against you.

So there is a hard ceiling: a score can never exceed its coverage percentage. A machine scored on 68% of the model cannot score above 68, however well it does on the components it did publish. The unpublished component is still excluded rather than scored zero - we do not invent a number or punish a machine for a fact we do not know - but it can no longer be used to lift the machine above what we were actually able to verify.

The effect is that publishing a specification can raise a score and withholding one can only lower the ceiling. When we introduced the cap the FoxAlien XE-Ultra went from 89 to 68, its coverage figure, and the fully-documented Genmitsu PROVerXL - scored on 100% of the model - moved up beside it. Every machine page and the database table still show coverage next to the score, so you can always see how much of the model a number rests on.

When we withhold the score entirely

The cap fixes one failure and exposes another. Score and coverage are two different axes, and below a point the cap collapses them: a machine scored on 30% of the model would show a number in the twenties, which reads as this machine is bad when the truth is we could not verify enough to say. Publishing that would be stating something false, which is the one thing this site exists not to do.

So below 50% coverage we withhold the number altogether and say which components we could not compute. The page still carries everything else - the full specification with the gaps marked, the components we could score, the price and the buying route - because a machine can be thoroughly covered and unscored at the same time. In rankings those machines appear in a separate band, with the reason stated inline, rather than being dropped: excluding a machine because its maker publishes less would punish the reader for the manufacturer's choice.

Prices in the maker's own currency

Not every manufacturer prices in dollars. Sienci Labs is Canadian and lists in CAD, and more non-US makers will follow. Where that happens we show the figure the manufacturer published, in the currency they published it in — “CA$1,890” rather than a converted number. A conversion moves with the exchange rate and was never a price the maker quoted, so presenting one as the price would be the same error as deriving a cutting area from a machine's name.

The value component still needs something comparable, so we hold a dated exchange-rate snapshot and use it for that calculation and for matching price-band alternatives — internal comparison only, never rendered as the price. The rate is committed in the codebase rather than fetched live, deliberately: a score that silently moved with the currency market would not be reproducible, and reproducibility is the whole promise of this model.

What coverage measures - and what it does not

Coverage is a statement about the manufacturer: how much of the model their published specification could fill. It is not a statement about our processing. That distinction had to be enforced rather than assumed - when we first seeded a CAD-priced machine its coverage fell to 53%, not because Sienci withheld a price but because we had no currency handling. The machine was being marked down for our gap.

A price published in any currency now counts as published. The cap and the sub-50% suppression rule key off manufacturer disclosure alone, so the number on a page reflects what a maker was willing to tell you - which is the only thing it ever claimed to measure. Correcting this moved the LongMill MK3 from 53 to 68.

Why we never derive a cutting area from a machine's name

Several manufacturers name a machine by its nominal size - “4x4”, “2x2” - without publishing the actual travel. It is tempting to convert 4 feet into 1219mm and fill the gap. We do not, and the reason is sharper than it first appears: the difference between nominal size and real travel does not run reliably in either direction. Carbide 3D's own specification sheet shows the Shapeoko 5 Pro 2x2 travelling 24.53″ against a 24″ nominal - the machine travels further than its name suggests.

Because the error is not even predictable in sign, a derived figure would be a guess wearing the clothes of a measurement. We record the maker's designation verbatim, label it as their designation, exclude it from scoring, and let the coverage figure carry the consequence.

The calculator model

Feed rate = RPM × flutes × chip load. The chip load is looked up per material and cutter diameter, then multiplied by a depth factor and a geometry factor. The recommendation targets the midpoint of the adjusted window, because published charts assume rigid industrial machines and a desktop router reaches its own stiffness limit first.

Chip-load anchors (mm per tooth)

Adjustment factors

Calculator outputs are estimates derived from published data and the stated formula. They are explicitly not test results, and this site does not claim to have measured them. The calculator cannot see your machine's rigidity, your cutter's sharpness, your work-holding, or whether your spindle holds its commanded RPM under load - which are exactly the variables that decide whether the arithmetic survives the cut. Prove every new setting on scrap.