Thread: Jointer technique

Not enough weight on the leading edge,
or
to much weight on the trailing section.

You want to keep moderate pressure on the timber just past the cutterhead once it has cleared the C/H. So basically you just stand in the one spot behind the C/H on the infeed side with you pushing on the timber on the outfeed side and guide the timber through

So the blades are set alined with the outfeed table (a touch higher is ideal)....what could be happening is the blades are slightly lower than the outfeed.....so as you push through its hitting the edge of the outfeed table..lifting it slightly continuiously as you push through,,,, causing a bow like that.

But how bad is the bow anyway.....What sort of rise over what length are you getting ?

Originally Posted by apricotripper

But how bad is the bow anyway.....What sort of rise over what length are you getting ?

Blades are aligned with out feed table, used a straight edge to set them and was very particular. I will drop the outfeed table slightly and see if that helps

Both ends are about 2-3 mm less than centre of board around 1000mm long.

I think DJ's Timber and Ivan in Oz are probably on the money. I need to practice my technique i think. I wont be able to have a play until Saturday but will run a lot of crapiata thru to practice on then.

Thanks for the tips.

I set my blades just a touch higher than the outfeed (like paper thickness or less) I found it makes a difference, and have had no hassle flattening boards with this method.
Obviously, you have the infeed table set slightly lower than the blades/outfeed
Also, Ive found better results come from light pressure on the board as you are passing it through. If you use too much downward force, the bent board will just spring up again after it has been passed through.
If you feel you need to use too much downward force, while pushing it over the blades, you are either taking too deep a cut, or the blades need sharpening (not in your case, as you've just had them done). With sharp blades, and a slick table, the wood just glides through with hardly any downward force needed.
cheers!

I normally apply very little downward pressure. Just enough to push the stock forward.

Too much pressure will force the board flat on the jointer, board gets cut evenly by the cutters, board leaves the jointer, bow reappears.

Sounds to me as if your out feed table is too high. The blades must be just slightly proud of the table, not level with it.

Easy way of setting it is to put a steel ruler on edge sitting on the out feed and touching the blade. Rotate the cutter head by hand and the blade will lift the ruler and carry it a couple of mm (read off the edge of the out feed) when it is at the right height.

yep. thats what I said. But he doesn't believe me.... its hard to say really.

Check for shyt on the infeed table too. Don't want any shavings or dust between your timber and the bed. That could alter things.

Try again maybe......take a few passes at the centre first to take that hump out...then make a full pass and see if its there again.

Probably shouldn't recommend it, If I was having that problem, I'd check everything......first thing I'd do is pull the guard away, get my eye down lower and push the timber through a bit and see whats happen at the cut on both beds.

Originally Posted by apricotripper

yep. thats what I said. But he doesn't believe me.... its hard to say really.

yes I do, gunna try.

Originally Posted by Geoff Dean

Blades are aligned with out feed table, used a straight edge to set them and was very particular. I will drop the outfeed table slightly and see if that helps

Originally Posted by apricotripper

Check for shyt on the infeed table too. Don't want any shavings or dust between your timber and the bed. That could alter things.

Try again maybe......take a few passes at the centre first to take that hump out...then make a full pass and see if its there again.

I'll give that a go too, willing to try anything.

Originally Posted by apricotripper

Probably shouldn't recommend it, If I was having that problem, I'd check everything......first thing I'd do is pull the guard away, get my eye down lower and push the timber through a bit and see whats happen at the cut on both beds.

gunna leave this one to the very last, don't like the possible ramifications.