Replies

1. 
   Dave_Wright_ | Mar 03, 2002 03:31am | #1

   *
   OK quick answer then too. Lower your outfeed table, just enough to even out the cut. Don't lower it too much or snipe might result.

1. 
   Scott_Braun | Mar 03, 2002 07:55am | #2

   *Sergio, At a 'glance', it sounds like your tables are misaligned. what you describe is what would happen if one or both of the far ends of the tables were slightly lower than the center. You might have to do some shimming...SB

1. 
   a_jepson | Mar 03, 2002 09:20am | #3

   *maybe your just putting all your pressure on the front of your board? if it's a problem with the boards being severely warped you can carefully lower the board over the cutterhead at it's midpoint or just before any severe bend, and take as many passes this way as you need to get the warp out of the end.

1. 
   Dave_Wright_ | Mar 03, 2002 04:02pm | #4

   *Sergio, I should add that your books might not help you with the outfeed table height fix. I've experienced it in my own shop though, and have seen a number of forum threads where woodworkers describe your problem exactly, lower the outfeed, and post back that the problem was solved.The basic issue is the relationship of the blade tip height and the outfeed table height. Manuals, books, and magazine articles disagree. Some say the make the knives dead level with the outfeed. Some advise setting the outfeed down - one even by as much as .010" if memory serves (a past FWW Q&A). I use about .002".You can verify your setting with a dial indicator. You can also do it on the cheap by setting a straight & smooth piece of wood on the outfeed overhanging the knives and rotate the knives slowly by hand. The sharp tip of a knife set at about .002" will pick up and carry the wood 1/8" before letting it go.Try lowering the outfeed first. It's very easy to do, doesn't require an expensive machinist's straightedge, and is completely reversible. Later on you can always try other fixes.Regards, Dave

1. 
   silver_ | Mar 10, 2002 07:37am | #5

   *Sergio,I think the short answer is: joint 1/16" about 2" into a board with a relatively straight edge. Shut off jointer.With 1/16th cut on back table, check if back table and cut are bang on. Usually the back table is a hair low when it tapers as you describe. With your 1/16th jointed section sitting on back table,raise until the back table just barely touches your jointed edge. Turn jointer on,joint your piece and check that there is no snipe at back end of board. If you're getting snipe, you're still low. A common jointer problem and 95% of the time this fixes it.Cheers, Silver

2. 
   Dave_Wright_ | Mar 10, 2002 03:28pm | #6

   *Silver (& Sergio),>> Usually the back table is a hair low when it tapers as you describe.With all respect, this is a common misconception. Assuming the tables are planar, tapering (cut depth decreasing as the board is fed) is caused by an outfeed table that is too high - not too low as you write. Here's how it happens:-- The first inch or so of the wood is cut straight - until it contacts the outfeed table's leading edge.-- The outfeed's edge was deburred during manufacture, which means that it has a very slight bevel. Being set too high, this bevel pushes the stock being fed upward. The error is probably only a few thousandths of an inch, so the operator doesn't notice either the teeny added drag when the lift occurs or the new height. An outfeed that is way too high will stop your workpiece dead, but one that is just a few thous high will create the result you are experiencing.-- For the next several inches, the cut will proceed at the downward angle determined by the outfeed table height and lower cutterhead circle. This will continue to tilt the workpiece further off the infeed table, though it will probably still not be enough for you to notice - you are, after all, looking down at the board instead of from the side while riding a loud and distracting machine.-- You will soon shift pressure to the outfeed table, and at that point the workpiece will lift entirely clear of the infeed. Again, you may not feel or see this happen. The angle will approximately double at this point until you are completely done with the cut. In severe cases and for shallow cuts, the jointer may stop cutting entirely before reaching the end of the board. This tilting effect can happen if the outfeed is too low also, but the depth of cut is actually increased then.The outfeed table should actually be slightly below the knives because the wood compresses under the knife pressure and springs back slightly downward after being cut. Therefore it takes a slightly low outfeed to be "level" with the knives. The amount of springback is affected by the species, moisture content, grain orientation, feed rate, and knife sharpness, but you can get good results with a single setting. I use .002" or a little more, but you will need to experiment to see what works best for your machine and woods.Regards,Dave

3. 
   silver_ | Mar 10, 2002 05:52pm | #7

   *Mornin' Dave,I can't leave this one alone.I don't know what .002 thou is or care. I come from the keep it simple school of woodworking. If the outfeed table is too high,rare for me, using the method I described, the board will either hit the outfeed table or lift a hair or two off the infeed table that you can see with your eye. Solution: lower outfeed until you see it below jointed edge of board, raise outfeed table until it just kisses edge;joint away. If you get snipe, the jointer is telling you the outfeed table is still too low by the amount of the snipe. I like easy and this works for me. Cheers,Silver