Replies

1. 
   saschafer | Jun 22, 2009 05:03pm | #1

   That can happen if there is a twist in the wood from one end of the plank to the other. You need to selectively remove wood from the high points at two opposite corners before taking full-width cuts. Alternatively, you can sometimes get away with gluing shims onto the low corners, but those can come off with explosive force if you're not careful.

   How much thickness discrepancy are we talking about?

   -Steve

    

1. 
   Ckenney | Jun 23, 2009 10:19pm | #7

   Thanks for the reminder. I checked the next batch and there was a small amount of twist, but not enough to cause a problem. I think it was a knife issue. (See below)Thanks, for the reply.Chris
   http://acornhouse.wordpress.com/
   a hobbyist's journey

2. 
   KeithNewton | Jun 22, 2009 07:33pm | #2

   I agree with Steve in that I suspected a little twist in the boards before you started.

   If that is the case, and you start into the cut by holding the leading edge flat against the table, this will cause you to keep planing until it is all taken out on the other end.

   I sometimes start by planing from the middle out each way. You can do this by bringing the board down in the middle, then pressing it to the outfeed table there, taking half of the twist out each way, before doing a final pass down its length.

   Another way it to use a hand held powerplane first. on the ends.

3. 
   AZMO | Jun 23, 2009 03:38am | #3

   Absolutely a twist in the board. I have been working some bath cabinets with QSWO and see the same thing. I flatten one 8" side and then run it through a thickness planer to get parallel sides, then back the jointer for a square edge.  Easy enough for short pieces on doors and drawers. With 5/4 stock you may only end up a 3/4" thick top in 4' long table tops.

   AZMO

                     

   -----------_o

   ---------_'-,>

   -------(*)/ (*)   http://www.EarthArtLandscape.com

   
   

   ---

   Edited 6/22/2009 8:38 pm by AZMO

4. 
   SteveSchoene | Jun 23, 2009 04:48am | #4

   As Steve Shafer has pointed out you have to work specifically on the problem of each particular board to get a flat surface on the jointer--particularly if you need to do it removing as little thickness as possible.  . 

   But, the jointer isn't designed to make boards of the same thickness.  For that you need a planer (thicknesser).  The two tools are really both needed as part of the process of 4-squaring boards. 

5. 
   RickL | Jun 23, 2009 04:57am | #5

   I don't really understand the nature of the problem from your description but I do know jointers as I have been repairing them professionally for over 20 years.
   Sounds like your knives are dull which would cause a tapering of the piece. As the knives dull the top edge of the knife goes below the surface of the outfeed table and causes the board to cut in the beginning of the board but it stops cutting as the board is passed over the head.

1. 
   Ckenney | Jun 23, 2009 10:23pm | #8

   Thanks for your reply. I think you hit the nail on the head. It was always the back edge, towards the fence, that was not planing. Which makes sense since that side of the knives would get more wear than the front side. They definitely DO need replacing. I started to try to do it, but many of the gib screws are frozen solid, and my smallish 8mm wrench, just can't muscle them free. Aside from a bigger wrench, any tips for freeing up frozen gibs?Thanks,Chris
   http://acornhouse.wordpress.com/
   a hobbyist's journey

1. 
   RickL | Jun 23, 2009 10:34pm | #10

   Get a better quality wrench.  Sometimes you have to cut them loose and replace the gib screws. Cutting half way through is enough to take the pressure off.  An abrasive wheel on a dremel is one way. A sharp tap with a cold chisel on the screw is another.  Take care in the direction the screw rotates.

   A bigger wrench should not be used to tighten or you will have the same problem loosening the screws.

1. 
   Ckenney | Jun 24, 2009 10:48pm | #14

   After a frustrating trip to (not-so-nearby) HD, Lowes and Sears; I came up short in a search for a decent quality, decent sized 8mm wrench. I know its a smaller size, but someone must make something useable.
   Any recommendations on a brand, or where to find one?Thanks,Chrishttp://acornhouse.wordpress.com/
   a hobbyist's journey

1. 
   RickL | Jun 25, 2009 04:02am | #15

   Sears should have one or your local auto supply store. Sometimes one has to grind the thickness a bit. Shouldn't be a complicated process/

2. 
   AZMO | Jun 26, 2009 04:20am | #16

   Us bike guys have great allen wrenches from Park Tools. I have found some other brands that are nice as well, but they are so worn I don't the brand.  Even so they wear our, and I grind down the ends to get to a fresh set of edges. 8MM is the size of bike pedals, so you can find those with a longer arm as well.

   Morgan                  <!----><!----><!---->

   -----------_o

   ---------_'-,>

   -------(*)/ (*)   http://www.EarthArtLandscape.com

2. 
   082250 | Jun 24, 2009 06:14am | #13

   Sometimes, the heat from the tip of a hot soldering iron will cause enough expansion/contraction to break the screw loose

6. 
   JohnWW | Jun 23, 2009 06:30am | #6

   Chris,

   Are you surfacing both sides of the rough stock on the jointer and finding that the thickness isn't even when you are done?

   Also is the set up jig the type where there are two small knife positioners connected by a bar, and the positioners sit directly on the cutter head and not on the outfeed table?

   John White
   Shop Manager for FWW Magazine 1998-2007

1. 
   Ckenney | Jun 23, 2009 10:25pm | #9

   Thanks, for the reply.
   I was jointing just one side, then to the planer for S2S. I think the problem is dull knives. (see above)The set-up jig is the Grizzly standard issue as you describe, sitting on the cutter, not the table. Is this a good thing, or a bad thing? (I did check the knives with the table after checking them with the cutter head.)Thanks,Chrishttp://acornhouse.wordpress.com/
   a hobbyist's journey

1. 
   mike4244 | Jun 24, 2009 02:41am | #11

   Make sure you are turning the wrench the correct way, my jointer uses left hand screws on the jib.Look in your manual or email grizzly tech if it is not apparent.A shot of wd-40 helps too.

   mike

2. 
   JohnWW | Jun 24, 2009 03:16am | #12

   Dull knives are a likely cause of your problem. On most machines the gib screws are conventionally threaded but you will be turning the screws so they go into the gib bar which can seem counter intuitive.The knives have to be parallel to the outfeed table, which is why, up until a few years ago, all knife setting tools worked off of the outfeed table. If you use the new style of tool, which was really designed for setting planer knives, there is a fair chance that your knives won't be set right.John W.

7. 
   Ckenney | Jun 26, 2009 04:30am | #17

   SUCCESS!!

   I finally managed to get the gib screws moving, and got my knives changed. Thanks to all who offered advice. I think it came down to three factors.
   1. I applied some penetrating lubrication (PG2000), which may or may not have helped.
   2. I rechecked the screws with a dial caliper and found that they are 5/16", not 8mm. An extremely small difference, but it makes a big deal. It would help if manufacturers would list what tools are needed for maintenance!
   3. At the suggestions of the Fine woodworking prof where I teach, Eric Mattson, I hit the wrench with a wooden mallet. I had tried a regular hammer, and I think the recoil lessened any benefit. The wooden mallet absorbed just enough for more of the force to be used; esp. with having a nice tight fit with the wrench.

   Now I just have to adjust the outfeed table a little higher to get rid of a little snipe (it was getting late when I finished the change), and I'm back to making piles of shavings.

   Thanks again, gang. Back to the bat cave!

   Chris

   http://acornhouse.wordpress.com/
   a hobbyist's journey