The router: the tool that votes on direction
Every other machine in the shop lets you decide how fast the cut happens. A router holds an election on every pass: feed against the bit's rotation and you win — the cutter pushes back, under control. Feed with the rotation and the bit wins, grabbing the work and driving itself along the edge faster than you can react.
Machines and tools vary by brand, model, and age. Your manual outranks this page — read it first.
The physics is the whole article: a router bit spins at 8,000–24,000 rpm, and wherever its cutting edge meets wood, it pushes. Meet that push head-on and the bit slows itself against the work like a wheel braking. Travel the same direction the edge is moving and the bit becomes a drive wheel — climb cutting — pulling the router (or throwing the workpiece) along the cut on its own schedule.
Which way to feed
There are two configurations and two rules, built on one principle:
- Handheld (bit pointing down, spinning clockwise seen from above): feed counterclockwise around a workpiece's outside edges, clockwise around an inside opening. Facing an edge in front of you, that means moving left to right.
- Router table (bit pointing up, so the rotation you see is reversed): feed right to left across the front of the fence, every time.
Experienced hands do use shallow, braced climb cuts to prevent tearout on squirrelly grain — taking a whisper of a pass with the router firmly against a bearing or fence. Know that it exists, and treat it as a technique to grow into deliberately, not to discover by accident.
Big bits spin slower
Speed limits on bits are straightforward physics: rim speed grows with diameter, and a 3-1/2″ panel-raising bit at a laminate trimmer's 24,000 rpm has its carbide moving well past highway speed. Large bits are marked with a maximum rpm — commonly in the 10,000–16,000 range — and belong only in a variable-speed router dialed down to match, and only in a router table. The marking on the bit is the limit; set the router to match it.
The router table's own rules
Table routing concentrates its incidents at one moment: the end of the cut, when the trailing hand — the right one, given right-to-left feed — passes closest to the spinning bit just as the resistance disappears. Push blocks and featherboards exist for exactly that handoff; so does the rule that fingers never trail behind the workpiece in line with the bit. Curved work without a fence gets started against the starting pin so the bit can't snatch the piece at first contact, and small parts get held with something sacrificial, never with fingertips bridging past the cutter.
Handheld, the remaining rules are grip and patience: two hands on the machine, the base flat and registered before the bit touches wood, and the motor at a complete stop before the router leaves your hands or gets set down (a spinning bit will walk a router off a bench). Bit changes happen with the plug out, like every blade change in the shop.
The router never hides its vote — the moment a cut feels like it's helping you along, it has taken over, and the fix is always the same: stop, and come back against the rotation. Feed against the bit on every pass and this is the most versatile tool you own.