Jointer Setup-What am I doing wrong?
Quickstep
| Posted in Power Tools and Machinery on
I’ve just replaced the knives in my jointer for the first time. What a painful process. There’s got to be a better way. Anyway, I set each knife so it juuuuust nicked a straightedge as the cutter passed TDC. This took forever as each knive would move a tinch when tightening the gib bolts causing me to start again from scratch. I test jointed two boards and held their freshly jointed edges together. There are gaps at the ends. They’re not snipes, but as if each board is tapering toward the ends. They’re not huge, but seems to me there should be none. Any ideas to help me?
Replies
Try this: once you've got your 1st knife set to the height you want, hold it down firmly with a board while tightening the gib bolts, one at a time. Then, go back to ensure it didn't somehow creep up on you, then if satisfied, move onto the next knife until you're finished. Be very attentive and patient and you'll find that things move better.
Marty
Thanks. What's causing the tapering effect?
"Tapering" can be also caused by the outfeed table being too high. Usually with the outfeed table too high it will produce an arc though. As you push the board across the table it will continually lift little by little with each inch because the table is higher than the bottom of the scallops the knives produce. This will vary with the speed at which you push the stock scross the cutterhead.
I forgot to mention in my first post but if the slide mechanism (gibs) on your outfeed table are too loose, the table will sag. These can be adjusted. To check this, unlock the table, grab the end of it and lift. If you feel slop, then it is too loose.
"There's got to be a better way." Mike described one in the following thread. I've not tried it yet, but it looks verrrrrrry promising:
http://forums.taunton.com/fw-knots/messages?msg=33444.10
re: the tapering problem, sorry I can't help. Are you sure your technique hadn't changed due to extreme post-replacement stress?
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I tried the glass thing. On my DJ-20, the first 2 inches of the outfeed table are aluminum. Instead of pulling the blade up to the glass, the magnet kept scooting around the end of the glass onto the cutter head. I think if my outfeed table were steel there would be enough downward force to counteract the magnet's tendency to scoot off the end.
PS, FG, did you ever decide if you'd switch to a helical cutter?
"PS, FG, did you ever decide if you'd switch to a helical cutter?" I wasn't considering switching (at any time in the near future) -- I was just very, very curious about how that magazine article matched up with real-life results and experiences. Gotta say, though, if I work with much more maple I might consider it!
"the magnet kept scooting around the end of the glass onto the cutter head." Jeeeeez, that had to be frustraing (but kinda funny too!).
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 2/19/2006 1:44 am by forestgirl
If you didn't check the stock before your first pass, and it was already slightly bowed, there may not be anything wrong with the jointer, but with your feed technique.
If you are jointing a board with the crown down, start out by setting the board down with the leading edge hitting on the outfeed table just behind the cutter. As you feed, do not alter the downward pressure toward the back end of the board.. There is a tendency to rock the board as you feed, which produces a rocker bottom.
Convex edge is a symptom of low knives, but if you can place a straight piece on the outfeed, and rotate the head by hand, if all knives touch, then that is not the problem.
I just looked it up in an old high school shop book. If the outfeed (rear ) table is higher than the cutting circle of the knives, the jointer will cut a taper. If your rear table is adjustable, first lower it below the knives and then raise it to exactly the height of the knives. If your rear table is not adjustable, you will have to reset your knives. On the other hand, if the rear table is lower than the knives, you will get end snipe.
It can also be caused by the tables bing out of parallel to one-another. I read a recent article about this, but can't recall which magazine it was...
Marty
Why is it that so few of the books and articles on jointer tune-up have a simple illustrations with the various mis-milled woods and what causes them? I know I saw a good example of such an illustration, but can't find it in the three books I have with jointer info in them.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
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