Jointer guide
What a jointer does, how deep a 6 in jointer cuts in one pass, the shortest and thinnest board it takes, and its safety rules, from the makers' manuals.
Jointer vs planer
A jointer flattens one face of a board and then squares an edge to that face: the board rides on the tables, so the cut follows a straight reference rather than the board's own shape. A thickness planer then makes the opposite face parallel to the first and brings the board to an even thickness. That is why the usual order is jointer first, planer second: the planer's cut follows whatever face lies on its bed.
Limits of a 6 in jointer
The median of three makers' manuals for 6 in jointers. Your own jointer's manual is the authority for your machine; use it where it differs.
| Limit | Value | Where it comes from |
|---|---|---|
| Deepest cut in one pass | 1/8 in | Median of 3 sources |
| Shortest board | 10 in (manuals: 8 in–12 in) | Median of 3 sources |
| Thinnest board | 1/2 in (manuals: 3/8 in–1/2 in) | Median of 3 sources |
Counted: RIKON, 20-600H 6" helical benchtop jointer operator’s manual (specifications); Grizzly, G0452 6" jointer data sheet; JET, JJ-6HHBT 6" helical benchtop jointer manual (specifications; operating safety). All read 2026-11-07.
Cutterhead speed, machine by machine
Speeds differ a lot between jointers, so there is no class figure here: each value is that maker's own.
| Jointer | Cutterhead | Speed |
|---|---|---|
| Grizzly G0452 | 3 straight knives | 4,800 RPM |
| JET JJ-6HHBT | 14 inserts in 2 spiral rows | 10,000 RPM |
| RIKON 20-600H | 12 two-sided HSS inserts | 12,000 RPM |
You feed a jointer by hand, so its cuts per inch depend on how fast you push. The cuts per inch calculator takes an estimate of your feed.
Safety
OSHA requires a jointer’s knives to project no more than 1/8 in from a cylindrical cutterhead, and a guard over the cutterhead on both sides of the fence (1910.213(j)(1), (j)(3), (j)(4)).
One source: OSHA, the federal standard , sources [1]
OSHA requires push sticks or push blocks for jointers (1910.213(s)(12)).
One source: OSHA, the federal standard , sources [1]
JET: never surface a piece shorter than 12 in or thinner than 3/8 in without a fixture made to hold it.
One source: JET, the maker of that jointer , sources [2]
Sources
For snipe, cutterheads and the planer itself, see the thickness planer guide.