Hello. I own a 6″ Sunhill Jointer, and recently, after running a white cedar plank over it, I noticed very faint knife marks on the wood. This is my first jointer and I was very careful to set it up correctly. Is my outfeed table a hair too low or is the cutterhead speed too slow? Thanks for all help.
Ken
Replies
Jointer marks show up for me when the blades are dull or when I move the stock through the jointer at a faster rate.
Think about how the cutter head and knives revolve. They actually scoop out the wood leaving scalloped shaped cutouts. The slower you move the workpiece, the closer together the the scallops are. Also, the shallower the cut, the shallower the scallops are.
You can't eliminate the scallops, just make them less prominant by taking shallower cuts and moving the workpiece slower.
Neither a jointer or planer is intended to eliminate final surface preparation. You still need to scrape and/or sand.
If the scalloped cuts are really noticeable, you may have one high knife. Recheck w/ a dial indicator.
Good luck.
Ken,
From my experience the marks that your jointer is leaving behind is due to pushing the material too quickly over the jointer or one of the three blades are out of alignment. As far as installing jointer knives I personally like the magnet set, which is just one way to install the knives. If you do not like the magnet set I would check out the "Oneway Multi-Gauge".
I hope this helps!
dogger
Howie is quite correct: because of the way the jointer works you can never get a completely smooth surface; there will always be scallops in the edge, large or small they will be there. But it is even worse than that.
The knives of the jointer also compress the wood fibers as they cut. The duller the blades the more they compress and the less they cut; but, again, even with newly sharpened, razor-edged knives, the wood will be compressed. When any glue with water in it is applied the compressed wood does expand once more--to some degree or other--but it would be a fantastic piece of luck if it expanded out to where it started. Even so, the connections between the fibers have been weakened by the process (take a hammer to the edge of a board and you can see a gross example of the same effect). All this--not having a true "straight" edge and weakened wood--obviously weakens the glue joint. I'm not talking about huge defects here, but the effects are there none the less.
The old timer who taught me most of the very little I know explained all this to me when I asked him why, after he used a power jointer, he then put the stuff in the front vice and took his joiner plane to it and shaved off several long one-piece transluscent shavings. (After I had watched this process over several weeks I asked him why he used the machine if he had to use the hand tool anyway. He looked at me as if I had just landed from mars; but the next time I visited him the power jointer was gone from his shop.)
There is a moral in all this somewhere. I know what I learned from it, but I don't want to sound too much like a heretic.
Alan
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