Parts of a Planer Machine – Thickness Planer Labeled

All 15 parts on the diagram

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The whole machine 7

Table Turning the handwheel moves it up or down. That sets how thick the board comes out.
Extension rollers They hold up a long board on its way in and out.
Handwheel It raises and lowers the table to set the depth of cut.
Depth scale It shows the height of the table, in inches and millimeters.
Return rollers A rest for the board as it is passed back. It goes over the top to the infeed side for another pass.
Dust hood It covers the outfeed side of the cutterhead. It joins the planer to a dust collection system.
Motor On this machine it sits in the stand. It turns the cutterhead through a belt. The feed rollers take their power from the cutterhead.

Inside the head 8

Anti-kickback fingers A row of fingers that swing freely on a rod. They let the board go in and are there to stop it being thrown back out.
Infeed roller It is grooved to grip the rough board. It is sprung down on the board to feed it toward the cutterhead.
Chip breaker It bears down on the board right before the knives. It supports the wood as it is cut.
Cutterhead It turns at high speed above the board. Its knives cut the top of the board down to thickness.
Knives They do the cutting. The dashed circle is the path of their edges.
Pressure bar It holds the freshly planed board down. That stops it lifting after the cut.
Outfeed roller A plain steel roller, sprung down on the planed board. It carries the board out of the machine.
Table rollers (bed rollers) They stand a little above the table. They turn as the board passes over, which cuts down friction.

How this list was compiled: Every name checked on 2026-09-30 and kept only where at least two independent sources use it. (1) A maker's 20-inch planer manual, full text at https://archive.org/details/manualsbase-id-251172 : infeed and outfeed rollers, chipbreaker, pressure bar, cutterhead, knives, bed rollers, table, table extension rollers, handwheel, scale, stock return rollers, dust hood, anti-kickback fingers, motor. (2) A second maker's 20-inch thickness planer manual, https://archive.org/details/generalmanual_000004588 : infeed roller, chipbreaker, cutterhead, pressure bar, outfeed roller, knives, table rollers, table, table extension rollers, handwheel, cutting depth scale, return rollers, dust collector hood, anti-kickback fingers, motor, gear box. (3) Two makers' benchtop planer manuals, https://archive.org/details/manualzilla-id-6311737 and https://archive.org/details/manualzilla-id-5643088 : infeed and outfeed rollers, cutterhead, blades, depth scale, infeed and outfeed tables, return roller. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's machine, nothing traced. Licence: own work

How it works

This is the woodworking thickness planer, the machine that planes a board to an even thickness. It is drawn from the side with a board going through, then cut through the head to show each part the board meets.

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What the board meets, in order

The board slides over the table rollers and under the anti-kickback fingers. The grooved infeed roller grips it and feeds it on. The chip breaker holds it down just ahead of the cutterhead, whose knives cut the top surface. The pressure bar holds the planed board down behind the knives, and the outfeed roller carries it out.

Setting the thickness

The handwheel raises or lowers the table, and the depth scale shows its height. The cutterhead stays where it is.

Small benchtop planers work the other way round: the table is fixed and a crank raises and lowers the head.
A planer for metal is a different machine with the same name. This page is the woodworking one.

Questions and answers

What are the parts of a planer machine?

A table with table rollers, a handwheel and depth scale, and a head that holds the anti-kickback fingers, infeed roller, chip breaker, cutterhead with its knives, pressure bar and outfeed roller. Extension rollers, return rollers, a dust hood and a motor complete it.

What does the chip breaker do on a planer?

It is a bar that bears on the board just ahead of the cutterhead. With the pressure bar behind the knives, it supports and controls the wood as it passes under the cutterhead.

What is the difference between the infeed and outfeed rollers?

Both are sprung down on the board and feed it through. The infeed roller comes before the cutterhead and is grooved to grip rough wood. The outfeed roller comes after, runs on the planed surface and is plain, not grooved.

What are the fingers at the front of a planer for?

They are anti-kickback fingers. They hang from a rod and swing freely, so a board can pass in under them, and they are there to prevent the board being kicked back out toward the infeed side.