Jointing making all boards have crook - Convex side down

[Alan Lightstone]

This one has me baffled. Basically, all the boards I'm running through my Felder A941 jointer are not getting straight, they are developing crooks with the wider part of the crook in the middle of the board on the edge that is getting jointed.

Never had this happen before. I'm not new to jointing, so I'm thinking my technique has been ok, but now seriously reconsidering that.

Jointed wood developing crook.jpg
Crook on Board Drawing.jpg

The boards I ran through (sapele) all had relatively straight edges, but rough, not finished.

Is there something out of whack with my jointer, or am I somehow pushing the boards through wrong?

I use two Magswitch dual roller guides set to the thickness of the board (one before, and one after the knives) to keep the board pushed against the fence.

I have absolutely no idea what is causing this. Any ideas?

[glenn bradley]

First indication is that the outer end of your table(s) is/are high. This path deviation would cause this result.

[Matt Day]

The simple answer is to do a jointer table/cutter head alignment. Have you done this?

[Alan Lightstone]

I thought of that Glen but the machine was commissioned by Felder upon arrival it’s never been moved and I never played with any adjustments so I don’t know why it should now be out of alignment suddenly.

[Alan Lightstone]

The simple answer is to do a jointer table/cutter head alignment. Have you done this?

I haven’t done this yet, as far as I understand the outfeed table should be aligned with the top of the cutter heads,correct?

That would show if the outfeed table is too high or too low, but the end being too high would be a level checking thing, right?

[Stewart Lang]

This one has me baffled. Basically, all the boards I'm running through my Felder A941 jointer are not getting straight, they are developing crooks with the wider part of the crook in the middle of the board on the edge that is getting jointed.

Never had this happen before. I'm not new to jointing, so I'm thinking my technique has been ok, but now seriously reconsidering that.

Jointed wood developing crook.jpg
Crook on Board Drawing.jpg

The boards I ran through (sapele) all had relatively straight edges, but rough, not finished.

Is there something out of whack with my jointer, or am I somehow pushing the boards through wrong?

I use two Magswitch dual roller guides set to the thickness of the board (one before, and one after the knives) to keep the board pushed against the fence.

I have absolutely no idea what is causing this. Any ideas?

First off don't touch the tables right away. Once tables are set for coplanar, they rarely ever move, and very often, don't. It's not going to be the issue if you've been getting good joints previously. Often what happens for me is the outfeed table will ever-so-slightly drop just a little too far below the knives. Check the outfeed table and adjust it ever-so-slightly. Run a board 6" over the head, and turn off the machine and adjust your outfeed table to just kiss it, without raising it. Even if it seems like it's already good enough, still mess around with it.

That's what happens to me every few months or so, my jointer (16" Moak) will start producing convex-ed joints, and the first thing I do is check the outfeed table height and that's ALWAYS been the case. I haven't adjusted the beds in years and have no need to. They're rock solid. But when that outfeed table drops just a few thou from where it needs to be, things get messy.

[Alan Lightstone]

First off don't touch the tables right away. Once tables are set for coplanar, they rarely ever move, and very often, don't. It's not going to be the issue if you've been getting good joints previously. Often what happens for me is the outfeed table will ever-so-slightly drop just a little too far below the knives. Check the outfeed table and adjust it ever-so-slightly. Run a board 6" over the head, and turn off the machine and adjust your outfeed table to just kiss it, without raising it. Even if it seems like it's already good enough, still mess around with it.

That's what happens to me every few months or so, my jointer (16" Moak) will start producing convex-ed joints, and the first thing I do is check the outfeed table height and that's ALWAYS been the case. I haven't adjusted the beds in years and have no need to. They're rock solid. But when that outfeed table drops just a few thou from where it needs to be, things get messy.

I have noticed that boards have started catching on the outfeed table as I push them through, so the table may have somehow moved higher, not lower. Could that cause this?

I've never adjusted the outfeed table (or frankly anything) on my jointer, so I'll have to find the instructions.

Erik, if you're listening, do you have a link for the instruction manual for the A941 that you can share?

[Stewart Lang]

I have noticed that boards have started catching on the outfeed table as I push them through, so the table may have somehow moved higher, not lower. Could that cause this?

I've never adjusted the outfeed table (or frankly anything) on my jointer, so I'll have to find the instructions.

Erik, if you're listening, do you have a link for the instruction manual for the A941 that you can share?

Haha yeah I've had that happen too sometimes. No idea how lol, probably just minute machine vibrations. Seems like you probably found the issue though. I'd reset the outfeed table height and see if it corrects it.

[Warren Lake]

the how is knife wear.

I have two settings marked on the jointer. One for facing a board and one for edging, those marks change as i go as the knives wear.

[Jamie Buxton]

That’s a jointer-planet, right? Perhaps the outfeed table is not latched down properly.

[Alan Lightstone]

OK, so I finally found the owner's manual, and adjusted the outfeed table height. It was too high. It was a royal PIA to adjust, because the locking nut must be loosened, and you need a very short metric wrench to reach it.

So, eventually I got it dialed in per the directions (which tell you to take a "gauge" and have the cutter move it 2-3mm when it is the correct height.

When I measured that with my digital height gauge, it came out as the exact height of the cutter.

Now the bad news - somehow the locking nut fell off, and I can't figure out how in the world you can get it back on, as the heavy cast iron table rests on the nut with no clearance above. So, likely, with vibrations the setting will change over time again. It was locked down rock hard before I made my adjustments. I put a large piece of sticky ass tape on the knob, and hopefully that will prevent large movement.

I made a test edge joint, and all looked well.

I'll take a digital level to the outfeed table later today to see if it is level or the trailing edge is high as has been suggested by several people.

[Alan Lightstone]

the how is knife wear.

I have two settings marked on the jointer. One for facing a board and one for edging, those marks change as i go as the knives wear.

Including helical cutters??

[Richard Coers]

I was taught an old fashioned way of setting out feed table height. Lower the table and get it to make a snipe at the end of the board. Then raise it just a tiny bit. Keep raising it until the snipe just goes away. I'm talking about moving the table just a few thousands at a time. I've also found that when the out feed table is set correctly, you can put a straight piece of wood on the out feed table and then rotate the cutter head by hand. It should lift the board and move it about 1/8" towards the infeed table.

[Osvaldo Cristo]

If I understand correctly you have a pair of guides forcing the board against the fence: if the board is not sufficiently thick and resistent, the preassure from those guides can bow up the board resulting the convex shape when released from lateral pressure.

Try to take off those guides.

This one has me baffled. Basically, all the boards I'm running through my Felder A941 jointer are not getting straight, they are developing crooks with the wider part of the crook in the middle of the board on the edge that is getting jointed.

Never had this happen before. I'm not new to jointing, so I'm thinking my technique has been ok, but now seriously reconsidering that.

Jointed wood developing crook.jpg
Crook on Board Drawing.jpg

The boards I ran through (sapele) all had relatively straight edges, but rough, not finished.

Is there something out of whack with my jointer, or am I somehow pushing the boards through wrong?

I use two Magswitch dual roller guides set to the thickness of the board (one before, and one after the knives) to keep the board pushed against the fence.

I have absolutely no idea what is causing this. Any ideas?

[Alan Lightstone]

If I understand correctly you have a pair of guides forcing the board against the fence: if the board is not sufficiently thick and resistent, the preassure from those guides can bow up the board resulting the convex shape when released from lateral pressure.

Try to take off those guides.

Those guides aren't like featherboards. They really don’t exert any real pressure - just keep things in line. It’s 4/4 sapele, so I don’t think it’s flexing. But worth a try also.