Replies

1. 
   RickL | Dec 18, 2006 06:40pm | #1

   Sounds like a simple case of your outfeed table being a few thousandths higher than the cutting circle. It's a common occurance to happen as the knives dull it creates this condition. Drop your outfeed table down and rise it back up slowly until the snipe from dropping it down goes away. It will take a few tries to get it right. Most likely you will go a bit high and recreate the conditions you have know but it's a good thing to learn how.

    It's a very common problem with jointer users...

1. 
   melonhead | Dec 19, 2006 01:18am | #2

   Hi Rick:

   This isn't a case of snipe at the end of the cut. The workpiece keeps getting thiner on the side farthest from the fence,and isn't getting cut at all on the side closest to the fence. It is as if the knives aren't parallel to the tables, but by using a straight edge to check them, they seem to be parallel.

   Bill

1. 
   JohnWW | Dec 19, 2006 01:52am | #3

   Then the tables aren't parallel.

   John W.

1. 
   melonhead | Dec 19, 2006 02:18am | #4

   Hi John:

   If both tables are parallel to the knives, aren't they parallel to each other by definition ?

   Bill

2. 
   RickL | Dec 19, 2006 03:50pm | #5

   Sorry. My answer wasn't on snipe but on what happens when the knives are set a bit low or dulled where they are below the outfeed table which is part of the the answer to your problem.

   If the knives are cutting on whatr you call the outboard or edge toward the operator and not cutting at the fence edge that would mean your knives are not set to the outfeed table. You didn't clarify how your knife setting gauge works but I'm betting it sets it to the head which would mean your tables can be perfectly coplanar and parallel but your knives will be off as you described. The cure would be to line up the knives with the table.

   If a dovetailed ways type jointer the tables were ground slightly off parallel to the bearing journals. Another possible fix is to shim the bearing journals if they are of the type that can be shimmed. If the jointer is a parallelogram type then the tables can be adjusted to the head.

   The simplest way is to line the blades up with the tables.

1. 
   Dan1120 | Dec 19, 2006 04:18pm | #6

   Another possible problem is your technique. Are you applying pressure at the back of the board? Always put only light pressure on the board, on the outfeed side of the cutter. On a board up to about 3 feet long, I start with my left hand on the left end of the board and my right in about the middle. As the board moves through the cutterhead, you can shift your weight to the right hand, but only after it passes the cutterhead.

1. 
   melonhead | Dec 19, 2006 05:33pm | #7

   Hi and Thanks everybody.

   Since my origional post I have double checked that the tables are parallel to the knives and each other ( coplaner) . I have run a couple of pieces of red oak over it without reproducing the problem.

    One thought is that the origional workpiece was slightly cupped which I didn't notice.  Since I was trying to remove the bandsaw marks I inadvertantly ran it cupped side up and put pressure more  on the edge away from the fence .

   The other posibility is that I have one of those machines I have read about that "prefers" to have the depth set by adjusting the table / cutting depth by starting with it shallower that the desired depth and lowering the table rather than starting deep and adjusting the table up to the desired depth.

   I probably should have just smoothed it with a hand plane .... it is only for a box lid. but I was in a hurry (late with a Christmas present ) and it seemed like a quick way to go. See how much time I saved.

   Thanks again,

   Bill

    

3. 
   highfigh | Dec 19, 2006 06:10pm | #8

   I have a Grizzly 6" jointer and after having the knives sharpened, reinstalled them and tried it. The cut was very smooth but I thought, "Oh, no! There's no way they could have all been ground the same and there MUST be some way I can make it better". OK, I'm a schmuck. Yes, they could have been ground the same and it took very little time to really mess the blade adjustments up. It did, however, take quite a while to re-adjust it so the cut was smooth again. In case you missed it, I'M A SCHMUCK!

   I had never needed to adjust the jointer and leaned a few things:

   1) How to check the tables to see if they're co-planar. Winding sticks work great for this and if they're accurate, they can give an immediate indication right at the mouth. A long straightedge works, too (positioned along the tables- if it passes over the front or rear and hits the other edge, it needs adjustment).

   2) Leaving the springs in place is a good way to become really frustrated. Either the springs OR the jack screws are needed, not both. I found this first-hand and by reading the posts here about jointer setup.

   3) Machinists do know/understand that whatever they grind as a set all need to have the same amount removed and their grinding attachments or dedicated knife grinders are capable of doing this very accurately. I probably shouldn't have doubted this fact but I did.

   4) Making a mistake in setting up the knives wasn't the end of the world. It took some time to be able to RE-adjust them to be the same height but I learned the other things in the process and next time, it will be a piece of cake.

   5) The adjustment gauge shipped with the jointer isn't the best way to go if the springs are in place. Much better if the jack screws are used.

   My jointer now surfaces wood better than ever and before this brain fart, I hadn't been using it very much. I thought it was pretty good before and now, I think it does a great job especially for a machine that wasn't particularly expensive. Re-checking the setup periodically takes time but it makes a huge difference. We did it in high school wood shop and I think the 30 years that have passed caused me to forget this fact. Annual checks and setup on all machines will ultimately save me quite a bit of time and lumber.

   For smaller pieces like what you were jointing, I think I would have used a hand plane. I think it would have been faster and you may have finished before you had the machine set up, considering test pieces, etc. Also, you won't have any knife marks from a jointer or planer and the grain visually pops better with hand plane use when they're very sharp.

   "I cut this piece four times and it's still too short."
4. 
   Rich14 | Dec 19, 2006 09:36pm | #9

   Melonhead,

   You've got enough replies to the problem you asked about - I won't add to that.

   But I do want to comment about the fact that you are using a jointer to surface plane a very thin (1/4") bandsawed veneer. That is extremely dangerous practice and should not be done.

   Please tell me you were pushing the 1/4" thick piece with a push block and not your hands! Even though you were taking very thin cuts, the thin stock could have shattered (exploded) and you would have been exposed to the rotating cutter head. Even using a push block, you could get seriously injured.

   The preferred method is to use the jointer to prepare a surface on the wood block from which the veneer is going to be removed. Then slice the veneer from the block with the bandsaw. The jointed surface is the "good" face that gets glued down to whatever substrate. The bandsaw marks get removed later by hand planing or sanding the assembled piece.

   Or, if you must have 2 good faces on the veneer, put it through a planer, good side down.

   Rich

1. 
   melonhead | Dec 20, 2006 02:45am | #10

   Rich:

   You are absolutely right and I am probably lucky. A momentary lapse in judgement is all it takes to get hurt. I was at least using a push block , but as you say the piece could have exploded. The spalting  in maple is caused by the wood being invaded by a fungus which can leave it on the 'punky' side and even more prone to comming apart.

   Hmmm .... maybe I need a new plane ... Oh Santa!...;-)

    

   Bill 

1. 
   Rich14 | Dec 20, 2006 04:59am | #11

   Yeah, Thoughts that go through one's head just prior to tragedy with a power tool . . . "I probably should have just smoothed it with a hand plane . . . "it is only for a . . . "I was in a hurry . . . "(I was) late with a Christmas present . . . "it seemed like a quick way to go . . . Glad nothing happened.