# Jointer safety, is there a minimum length and thickness?

What is the minimum length and thickness of a piece of wood to be used on the jointer?

• it really depends on the geometry of the tools. The size of the piece is limited by the gap between the beds and knives on the jointer, and rollers and knives on the planer. for run of the mill tools (6" jointer, 12" "portable" planer) this works out to about 10-12". – aaron Mar 12 '18 at 13:07
• Minimum length for the planer has already been covered here, link, so I've just edited the Question to leave the query about the jointer. – Graphus Mar 12 '18 at 15:54
• To whoever voted to close as too broad: very funny. ;-) – Caleb Mar 12 '18 at 21:46

What is the minimum length and thickness of a piece of wood to be used on the jointer?

That depends on the jointer, and to some degree on the depth of cut. With respect to length, you want significantly more wood on the infeed or outfeed table than in the space between them. Having plenty of wood on the tables does two things:

1. it helps you keep your hands away from the cutting head

2. it gives you plenty of bearing surface and leverage to keep the work traveling parallel to the tables and resist tipping into the space between the tables

Check your owner's manual for the manufacturer's recommended limit. For the 6" jointers that many of us have in home shops, I don't think I'd be happy jointing a piece shorter than about 12". If you're jointing short pieces, take light cuts: setting your jointer to remove only a little wood at a time will minimize the width of the opening between the tables, and also reduce the force that the cutter can apply to the work.

With respect to thickness, the work should be thick enough that it won't flex as it passes over the cutting head. If the work flexes as it's being cut, it's not really being flattened.

If you have any doubt about whether a piece is long enough or thick enough to be jointed safely, use a different method. A hand plane provides excellent results with little fuss. A router and a straight bit with a bearing or guide bushing and a good straight edge also work well.