Jointing long stock

[Nathan Yeager]

I am fairly new to woodworking and am having problems edge jointing long boards. I have a small 6" benchtop jointer, and am currently attempting to square up boards that are 5 feet long. I find that after jointing, the edge to face angle is a true 90 degrees, however the edge itself is now concave over the length of the board.

While my blade height is set to 1/32", there appears to be ~1/8" more material taken from the middle portion of the board than from either the leading or trailing ends. I am dumbfounded and cannot understand how this is occurring.

I have focused on not applying any downward pressure other than what is ncessary to keep the board steady. I am also fairly certain that I am not raising, then lowering, the blade as I run the board across it...I have lived with this situation for my previous projects, and just clamped the heck out of panels I am gluing up. I've read that the concave situation is better than convex, but I'd rather just have 2 nice edges to glue up...

Thanks in advance for any advice.

[Michael Ballent]

I try to keep the blades even with the outfeed of the table. I have seen this happen when the blades are proud of outfeed. The quickest way to check is to lower the infeed table to take a 1/8" cut and edge joint about 3-4" on some 12" or longer scrap. Turn off the jointer and look to see if the part that is over the outfeed is touching the outfeed side. If you have a set of feeler guages it can make it easier to determine, but a piece of paper is about .004" thick too . If there is a gap between the wood and the outfeed, then raise the outfeed until it touches the part you have just jointed. The rest is technique

Also you should be shifting the pressure from the infeed to the outfeed side as you make the pass... You start with all the pressure on the infeed side making sure that the wood is against the fence... then as you have have 1-1.5 feet on the outfeed you apply the downward pressure on the outfeed side, with no pressure on the infeed side.

[Nathan Yeager]

Thanks for the hint. I will check the outfeed height tomorrow. Would check tonight, but doubt the neighbors are as concerned about my problem as I am.

[Michael Ballent]

Just offer them some Krispy Kreme's as they leave in the morning

Thanks for the hint. I will check the outfeed height tomorrow. Would check tonight, but doubt the neighbors are as concerned about my problem as I am.

[Dan Forman]

Nathan---Sounds like your infeed and outfeed tables are not co-planer (tables are not parallel). Here is a link to a jointer tuning page; the first example deals with co-paner issues. http://woodworking.homeip.net/wood/T.../Jointers.html

Dan

[Deirdre Saoirse Moen]

In addition to the co-planar issue...

Since you're trying to joint boards longer than the length of the bed, what I used to do was to get infeed and outfeed tables to help support the stock at either end. And I made sure they were dead level to the infeed and outfeed portions of the jointer, too.

Get a 3-4' straightedge, put it on the edge of the infeed or outfeed table, adjust infeed and outfeed table so that there's no gaps when the wood goes onto or comes off of the jointer.

This won't fix the co-planar issue, but it may reduce any other issues you're having.

(edited to add: I say "used to" because I don't currently own a jointer)

[Don Henthorn Smithville, TX]

Your blades should not be moved once they are set. You raise and lower the infeed table to adjust for depth of cut. The blades should be even with the outfeed table. To acomplish this, lower the outfeed table a slight amount below the blades. Run a two foot piece of wood through the jointer and notice the snipe on the end of the board. Raise the outfeed table a TINY increment and run the bord through again and check for snipe. Keep raising the table in TINY increments and run the board through until the snipe just disappears. Lock the outfeed table in this position and you should not have to change it until you remove the blades for sharpening or replacement. Hope this helps.

[Nathan Yeager]

Thanks for the tips, though I have not corrected the problem.

I verified the infeed & outfeed tables are in the same plane. I utilized both the straight edge & 2 90-degree squares methods. I can detect nothing askew. I suspect I am not using the tool correctly.

[Cliff Rohrabacher]

Raise the outfeed some more - just a schos.

Some folks prefer a slightly concave joint geomety. The idea (I believe) is that it prevents the ends from pulling apart.
I have seen this pull-apart at the ends happen in 2" and 3" thick maple butcherblock slabs It's heartbreaking when it happens.

I am unsure that prestressing the joint in such a manner is the best idea especialy when using a Polymer glue as the glue will always be in a state of plastic flow because - well- it will always be a plastic.

[Tom Jones III]

I don't understand some of the suggestions here, I was under the impression that if the outfeed table was not 0.001" or 0.002" lower than the blades then the wood would be tapered towards the trailing edge.

I just got finished jointing 6 boards 5' long on a PM 54 short bed jointer. It is tough and your machine had better be in top form and your handling must be excellent.