When the jointer jams...

[Art Mulder]

I have a 6" Delta x5 jointer. Bought it 10 months ago or so. Before that, my only jointing was done with an old Stanley #7c.

My understanding is that you should joint a board with the concave face down. If you put the convex face down, it could rock, giving you grief.

My problem is this: I put the board concave down, and push it along the table into/over the blade. The blade cuts off the front bit of the board, and now the board rests lower and instead of clearing the rear table, it bangs into it and stops dead.

What is the proper and safe way to handle this?

As far as I know, the jointer is tuned correctly, the blades are installed correctly, and the rear table is at the correct hight. Boards that are mostly flat go through the jointer with no problems.

[Kirk (KC) Constable]

When that happens, if you pull it back and start over it'll usually go.

KC

[Ian Gillis]

I always start on the convex side. Balancing the piece on its "hump" and removing some of the compression wood helps get the board flatter faster. Starting on the ends of the concave sides often means that you have to remove a ton of material to achieve flatness - often leaving the ends thinner than you want.

If you plane the humpy side, the board will often "relax" quite dramatically - maybe 1/2" or more, meaning fewer passes and less time to flatten one face. After the initial passes on the convex side, you may decide to flip the board over and joint the hollow side - you'll still be ahead of the game because it will be less hollow than before.

Same applies for handplanes.

Cheers

IG

[Mark Singer]

Ian is correct...but the technique of making a flat spot takes experience and I have found many people have problems with jointer technique. You must feel the flat spot you are making and apply pressure on that spot. That is why concave down is normally suggested. I sight the board and if its really bad straight line it on the tablesaw using an aluminium extrusion as a straight edge a level works well also. The same is true for handplanes as Ian statedfind the flat area and work from there....I keep a straight edge and a square handy just to check....1 degree off and you have a coopered table top:rolleyes:

[Mike Cutler]

Ian.

I never knew that. I'll have to try that next time.

Art.
If I have boards with that much of a concave to them, I draw a line along the edge and hand plane, or power plane both ends until it's closer to true and will feed properly. I'll also just freehand it through the bandsaw. You can alternate ends through the jointer, but one way is going to make a lot of chatter as the grain is caught. You're just trying to knock it down enough to joint. This works the same for edge, or face jointing.

As far as setup. I doubt if my jointer removes a 32nd on each pass. I joint slow.

[Ian Gillis]

I don't disagree with anything Mark said, but I thought we were talking about jointing a face and not an edge. You can use a tablesaw to joint an edge. My favourite was a sliding panel saw with 10 ft of travel and 10 hp :D

Jointing a convex face does mean deviating from the "textbook" method of jointing the full length on each pass, but it is standard operating procedure among all the experienced people I've worked with.


As always, if a procedure doesn't feel safe, don't attempt it.

IG

[Mark Singer]

Ian,
You are correct I was talking edge...face is the same story as you said...and shorter passes is what I do ...."skip" we call it here... I have a friend that makes wood windows and doors.....he says it is really difficult to find someone that can run a jointer....read the board and the grain and not turn nice stock into garbage.....it takes a little sensitivity,,,,just think about each piece

[Art Mulder]

I don't disagree with anything Mark said, but I thought we were talking about jointing a face and not an edge. You can use a tablesaw to joint an edge.
...
Jointing a convex face does mean deviating from the "textbook" method of jointing the full length on each pass, but it is standard operating procedure among all the experienced people I've worked with.


Actually, I specifically did not say if it was face jointing or edge jointing -- the reason is that the same thing happens for both.

This is quite fascinating. I have never ever heard of someone recommending to joint the concave face first. Something new to try...

[Steve Clardy]

I don't normally face joint anything. Just edge joint.
If it jams, I usually back it up and it goes on through the second time.
If not, raise it slightly.

[Chestnut Tool]

Try attachment again.

http://www.sawmillcreek.org/attachment.php?attachmentid=47617&d=1159327924:

Wow! Was that confusing. The attachment above is just a regular post. I couldn't get it to stick here any other way. Sorry.

[David Rose]

Art, didn't you say...
_________
"My understanding is that you should joint a board with the concave face down. If you put the convex face down, it could rock, giving you grief."
_________

Sounds like "face" to me. Twice even... :D

I'm not trying to be persnickity. I just read the same as the Ian. Once the face is flat, the edges are easier. Usually, the bandsaw works over my first edge.

I do like Kirk and pull back and run again when that happens. However, I had not experienced or heard what Ian said about stress relieving better when the outside of the curve was cut first. That is good news! I'm going to try that on the next few pieces that are cupped.

I use a lot of s2s that is not too "s'ed" on the "s" sides. :rolleyes: Even after much digging through the stacks, I seldom find a flat board. I look for enough thickness to get it flat most of the time.

David


Actually, I specifically did not say if it was face jointing or edge jointing -- the reason is that the same thing happens for both.

This is quite fascinating. I have never ever heard of someone recommending to joint the concave face first. Something new to try...

[Steve Jenkins]

I agree about jointing the convex face first. It really does help the board "relax" and takes fewer passes to get straight. Often I will work the convex face a bit then flip the board over and place the center over the cutterhead and joint off the trailing end then spin the board around and do the other end from the center. There is no law that says you have to make a full pass over the cutterhead each time.

[Art Mulder]

... then flip the board over and place the center over the cutterhead and joint off the trailing end then spin the board around and do the other end from the center. There is no law that says you have to make a full pass over the cutterhead each time.

Maybe not a law, but I am under strict instructions from SWMBO to keep all ten of my fingers. If I understand your method, Steve, what you describe would require propping open or removing the blade guard, and dropping the board down over the spinning cutter.

I'm rather reluctant to do so.

Wouldn't it have the same effect to feed in the board from the end, but only go until the blade stops cutting (due to the bow/arch in the wood), lift it off, and then repeat from the other end? that would seem safer.
Of course, why not just run the whole board? What are you saving?

[David Rose]

Art, Steve can probably better explain what he is doing. But I think I do the same a lot. If I set the middle of the board down on the guard of my old Delta jointer, and push it forward gently, it will push the guard back in a few inches of board movement. It is no less safe than other cuts on the "meat grinder". I almost always use push paddles/sticks for feeding. One exception is when I can hook fingers over the fence. I always ask myself where my fingers will go if the board "goes away". My mind kind of automatically gives me a "play" of what the first body parts to contact the cutter would look like. I think that comes from my age. :eek:

I just happened to think that what I am doing is dealing with a board concave "end to end" not "side to side". This may not be what you meant. And I think there is a different term for this kind of warpage. But I can't remember what for sure. :o

What usually causes my cupped boards (concave side down) to catch, is that the trailing end of the board is not supported by my short infeed table. As the board is pushed farther across the cutter, the tail end of the board rises as it comes over the edge of the infeed. This causes the end of the board going past the cutter to dip slightly and catch on the infeed side of the outfeed table. Does that make sense?

If you feed the trailing end of the board over the cutter a couple of cuts, then use that end of the board for the leading edge, you will likely have a slight bevel (in your favor to clear the outfeed table edge). Of course you will cut it away in a pass or two, but that is often enough to take care of a slight bow. Bow! That's it! Is that what we are speaking of, or is it side to side cupping?

When you run the full board through only taking minute cuts off either end, you are cutting air most of the time. Sometimes, with a short board, it takes less time to just go ahead and go full board. But if you cut air for 4' in the middle, it may save some time to lift the board and cut what will cut.

David