Replies

1. 
   rslatm | Dec 19, 2003 07:23pm | #1

   Could be one thing or a combination of things. If you  search the archives you will find this question has been addressed before. Your instruction manual should have some answers as well.  Jointers can be complicated.  Recommend you get...

   http://cambiumbooks.com/books/woodworking_machines/0-8069-6755-2/
2. 
   DonC | Dec 19, 2003 07:31pm | #2

   Measure the height of the knives above the cutterhead. All 3 should be the same.

   Don

3. 
   forestgirl | Dec 19, 2003 07:44pm | #3

   Could, as mentioned, easily be a combination of factors.  Jointers do need to be "tuned up" and technique can take awhile to develop.  I'll throw out another book title for consideration:

   Jointers and Planers:  How to choose, use and maintain them
   by Rick Peters
   ISBN:  0-8069-6755-2

   forestgirl Another proud member of the  "I Rocked With ToolDoc Club" .... :>)  you can take the girl out of the forest, but you can't take the forest out of the girl ;-)

4. 
   JohnWW | Dec 19, 2003 08:42pm | #4

   JP,

   Since you have a new machine, by far the most likely cause of your problem is the outfeed table being set too low.  I would be surprised if this weren't covered in the machine's manual, but few manuals are really complete and clearly written.

   To set the outfeed table height, you need two decently flat boards around three feet long.  Lower your outfeed table a little bit more so it is definitely lower than one of the knives on the cutter head when the knife is at the top of its arc.  It doesn't need to be a lot lower, just a 32nd of an inch or so.

   Now take a pass on each board using the proper technique, applying pressure on the outfeed side as soon as there are 8 to 10 inches of the board past the cutter head.  After making the cuts, place the two planed edges together, they should be obviously convex.  Now raise the outfeed table a bit and repeat the test.  The difference between the right height and too low is only a very tiny amount, so make only small adjustments. 

   As the table is raised closer and closer to the proper height, the edges will become straighter and the gap between the boards will diminish.  When the boards mate perfectly or still have the tiniest gap, the table will be at the proper height. 

   If you overshoot, drop the table and begin over, if you try to drop back down to the correct setting, the table height will probably slip lower later and cause problems.  Cutting especially hard or soft woods or dulling of the blades may require, at some point, that you reset the oufeed table height for the straightest cut. 

   There are other possible causes for your problem, unequal knife height not being one of them, but they are all far less likely.  There are a number of good books about maintaining power tools, you should get one.

   John W.

   
   

   ---

   Edited 12/19/2003 6:52:42 PM ET by JohnW

   
   

   ---

   Edited 12/19/2003 7:20:07 PM ET by JohnW

5. 
   fretmaster | Dec 19, 2003 11:32pm | #5

   Not sure if JohnW is John White or not... but I've got John White's book on maintaining shop machines with simple to make and inexpensive jigs / tools.. I reccommend it to anyone that wan't to keep a precision shop.  New tools, I have found, are not immune to problems like your having.   Also when moving and shipping, things could move on you.  I have also found this problem to be caused by my own old craftsman jointer when the infeed table is not parallel to the outfeed table.  John has an excellent section on jointers in this book:

   http://www.amazon.com/exec/obidos/tg/detail/-/156158424X/102-6409706-1265768

   Good luck,

   Also here's some video's with John's advice on tuning up a jointer when it's a knive problem:

   http://www.taunton.com/finewoodworking/media/wvt056.mov

   Hey John, if I'm seeing small grooves in my jointed boards, and my tables are parallel.. does that mean that my knives need to be reset???

   Thanks,

   Fred

1. 
   scooter1 | Dec 19, 2003 11:52pm | #6

   That Delta has a nifty self adjustment. Just loosen the three bolts on the gib which holds the knives tight. Take out the knives and check the springs under them. Re-insert the knives and tighten the bolts almost tight. Put a straight edge on the outfeed table and loosen the bolts so the springs force up the knife to the straight edge. Tighten the botls. Repeat for the other two sets of knives.

   I'd try this before any other procedure. It is Delta preferred method and works great!!!

   Regards,

   Boris

   "Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934

2. 
   JohnWW | Dec 20, 2003 12:46am | #8

   Fred,

   Are the "grooves" lengthwise and actually slightly raised or are they very regular crosswise shallow cuts, sort of a slight scalloping?

   In the first case, the knives have a nick in them and shifting a couple of them sideways, each by a slightly different amount will give you a good cut without having to resharpen the blades.  Usually the only way to do this is to loosen and reset all three blades as though you were installing a new set.

   The second case is probably the condition you are describing.  It is caused by the knives being at slightly different heights, usually just one of the three being slightly higher.  The effect, as the board moves over the head, is that there are two shallow cuts followed by a deeper one from the high knife.  If you place a wood block on the outfeed table so it overhangs the cutter head, and then rotate the head by hand, you should be able to spot the knife that is out of line. 

   The solution is to reset the knives.  Depending on the knife setting system you use, it is usually easier to reset all three knives than to try to get the one offending knife at the same height as the other two.

   I just thought of a third possibility, if there is a lengthwise groove in the wood, there is a raised burr somewhere on the jointer table, usually along one of the table edges that overhang the cutter head opening.

   John W.

1. 
   fretmaster | Dec 20, 2003 01:41am | #9

   >> very regular crosswise shallow cuts, sort of a slight scalloping?

   EXACTLY what is happening...I had recently purchased some 6 1/8 blades (Frued) from amazon for my old crafstman jointer.  The outfeed table is cast to the base and the infeed has 4 screws to get the infeed parallel with the outfeed.  What I did to set the blades was kind my own thing.  After getting the infeed parallel to the outfeed, I tried my best to find the absolute center line where the blades would be in the highest point of the cut.  I clamped a straight edge to the table to kind of be a fence for my dial indicator with a magnetic base to slide so that I could check both sides of the blade height.  I slid the indicator down the fence and checked the height at both sides after 0'ing it with the edge of the outfeed table.  Then I tried to get the blades set to within .003 of that mark.  There were some small variances with the actual outfeed table where it was machined, but I thought it was good.  Perhaps when I tightend the wedges down they moved somewhat??  I need to make the magnet jig as described in the book.. that seems to be a better way to do it.. what do you think?

   Thanks,

   Fred

1. 
   JohnWW | Dec 20, 2003 02:49am | #11

   Fred,

   Trying to set up fixed outfeed table jointers is always a challenge.  The simple theory is that the blades should be set at exactly the height of the outfeed table, but the vagaries of wood and metal often result in the true best height for the outfeed table being a few thousandths on either side of the theoretical best height.  With an adjustable outfeed table you can fine tune the table's height to get a straight cut, the fundamental fault of fixed table machines is that they can't be fine tuned after the blades are installed. 

   You may find, through experimenting, that placing a thin shim between the jig and the table, to raise the blades, or between the jig and the blades to lower them, will result in a straighter edge on the stock you are planing.  Cigarette rolling papers are a good shim material for making such small adjutments. 

   Using a magnetic jig to set the knives is usually both faster and more accurate than using a dial indicator.  I found that by using a magnetic jig I could regularly get all three blades set to within a thou of each other without fussing.  Our sense of touch and vision can easily feel and see a step of .003 inch on a piece of wood, so your blades being off that much in height would produce a noticable scalloped edge.

   Since thousandths count when setting blades, it is important that the locking bars and gib screws all work smoothly or they'll shift the knives when they are tightened.  It is especially important that the heads of the screws be symetrically rounded or pointed, depending on their style. or they will almost always shift the blades position.

   John W.

   Edited 12/19/2003 7:24:52 PM ET by JohnW

1. 
   15Broad | Dec 20, 2003 02:40pm | #12

     When adjusting/replacing blades on my 6" Delta I've been using a flat plate from the outfeed side slid over top of the knife.  It's just narrow enough to allow me to secure the end screws to hold the knife in position, I then remove the plate, tighten all screws and re-check.  I've had good success planing the 710 pieces of oak for my living room floor and any other lumber I've planed so far.  The hard part is ensuring the knife is at it's apex.  Perhaps the dial indicator should be used to find that and a pencil mark on the fence for reference, rather than apexing by eye.  I find it easier to be consistent with the plate than using the ruler method laid out in the manual.  Whether I've just been lucky remains to be seen, but so far, so good.

2. 
   patternmaker | Dec 20, 2003 04:29pm | #13

   Raise the outfeed table until the test board jams against it.Now gradually lower the outfeed table until the test board just slides by. For my jointer this is the right height.Now carefully turn the outfeed adjustment to just take up the slack that may be in the linkage.

   Work safely ¬¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬¬

2. 
   Tao | Dec 21, 2003 10:03pm | #14

   >>The outfeed table is cast to the base

   Here's a low tech way of seeting jointer knives to a fixed outfeed table:

   I have noticed that when cutting "just right", the knives arc just a tiny bit above the surface of the outfeed table.  I don't know it it's even 001".  When I put a good straightedge on the outfeed table and let it just hang over the gap between tables, each (sharp) knife pulls the straightedge forward about 1/8" as it passes by.

   Observing this, a strictly pragmatic, non-theoretical approach would be to adjust each end of each knife so that it carried the staightedge forward about 1/8" to 3/16".  That way they'd be set to the same position as they would be in a properly working jointer.

   As far as adjusting a movable outfeed table, I take a slightly different approach.  A table that is too low will leave a short snipe at the tail end of a board as it goes through.  I just drop the table, and raise it back up until the snipe just disappears.  At that point, I joint two boards and put them together to double check.  Rather than trying to look for daylight through the joint between the boards, I just look at the joint.  When they are jointed perfectly, there won't even be a dark line visible anywhere along the joint where the two pieces meet.

   FWIW

   Michael R

6. 
   ron61 | Dec 20, 2003 12:45am | #7

   Before I would start adjusting knives check them may not  need adjusting.

   You are saying it is cutting a convex " rounded" not convex? "cupped"

   It a good idea to check the knives but sounds like the out feed table - I am not sure how close they need to be but as long as your high blade is at the same height on each end it should be ok it may not stay sharp very long " the one knife doing all the cutting" I would guess if they were with in 3 or 4 thousandths it would be ok.

   I would check the out feed table it needs to be the same height as the highest knife and parallel with the infeed table - I'm guessing that it is not parallel with the infeed table .

   My jointer the end of the table is a tiny bit low and cuts a very slight concave in the edge so I left it along for a sprung joint for glue up.

   check this out     http://web.infoave.net/~deltoro/jointer.html
7. 
   JMartinsky | Dec 20, 2003 02:45am | #10

   I haven't read all of the other posts, so this may be redundant. If I understand what you are saying, then I would suspect that the outfeed table is running "uphill" in relation to the infeed table. I.E. the tables are not parallel to each other. That is the only thing that I can think of that would cause a "convex" (outside) as opposed to "concave" (inside) surface. Hope that helps. Good Luck!

   Peace To All,

   John

8. 
   Joe11 | Dec 22, 2003 04:17pm | #15

   Hi All,

   I've been out of town for the past 2 days and haven't had any time to do any adjustments to my jointer, but when I do I'll be a lot better informed thanks to your help.

   Thanks very much for all your comments and links it's appeciated.

   Joe