Jointer question

Re: Jointer question

Barry Irby

That was my first thought. A jointer depends on the number of cuts per inch to develop a flat/smooth surface. If you push the board through faster, you develop scallops. Fewer knives means more scallops. Some jointers have only one knife and if you go very slowly you get a pretty good surface. The RPM's of the head have a similar effect.

Use a steel rule to check the blades. Mark the knives with a magic marker so you can identify them. With the machine unplugged, set the rule on edge on the out feed table and turn the head toward the operator end. Note how far the rule is dragged. Do this on both ends of each knife. With the out feed table properly adjusted or the knives set correctly, the rule should move the small amount each time. I find mine works best when the knife just snicks the rule and moves it about an inch.

Face jointing a knotty snarly piece can be something of a rough ride anyway. Sharp knives help. Firm pressure with push blocks helps also.

Easiest way to check...

John in NM

Swipe the bevel of each blade with a marker, then joint another board. If the ink wears off evenly between all three, they are set at the same height.

Re: Easiest way to check...

Howard Pollack

That is very clever.

Re: Jointer question

Steve jenkins

Knives may be dull. Makes face jointing feel bouncy more than edge jointing.

I stole it!

John in NM

Wish I could claim credit for that one, it was the procedure in a shop I worked for in the 90's.

Something else if edge jointing is fine

Dick Coers

You can't get one fine cut, and one horrible cut with one high blade. At the rpm of the head, you can't even see an issue unless you are throwing the wood through the machine.

Re: Jointer question

Dave Bair

You say the wood has a decent finish. Any chance it is being burnished?

Re: Jointer question

Yonak

Dan, oftentimes, when face jointing an uneven board, the first pass through can be rough .. really rough sometimes, especially when it first catches the leading edge. Once the board starts getting more flat, the go tends to get smoother.

Also, you might be taking too much of a cut.

Re: Jointer question

Dan Bundy

It was a pretty smooth face to begin with, and the initial "bite" was pretty rough. I reduced the cut for a second pass and it was still pretty jumpy.

It is possible (actually likely) that the blades are dull as it's been a while since I sharpened them, though it doesn't get a lot of use.

Looks like I've got a couple of projects to occupy my social-distancing time.

Thanks for all of the input.

Stay safe and stay well.

Re: I stole it!

Clementine

Will Durant said of Shakespeare: "What he stole, he made better."

But

Mark Mandell - Gone Round In New Jersey

He couldn't make Bacon better!

Re: Two birds with one technique

TomD

A simple way to check blade height and set-up at the same time is to disconnect from power, and make it so you can roll the head easily. Place a straight piece of wood, or possibly a straight edge with tape on the edge, along the outfeed table, so it rests over the blade head. roll the head forward in it's normal rotation. It should move the "ruler" toward the infeed table, about an inch. This increment should be the same for both sides of the blade, and all the blades. You can mark a line on the ruler, and align it with the edge of the outfeed table, then mark it where it comes to rest after you turn one blade forward. The same set of lines should work for all the blades and all locations on the blades.

It may seem counter intuitive, but for most jointers, proper set-up is with the blades higher than the outfeed by a fraction. The exact correct degree is adjusted by an adjustable outfeed, or blade leveling system. It is correct when your edge jointing comes out straight or sprung to the degree you prefer. This is a very slight degree of elevation in the blades, probably invisible, which is the reason you have a technique in set up for determining it. But it will also spot a problem in the blade level.