# Jointer giving my boards a gentle curve



## beelzerob (May 2, 2010)

I recently got a replacement Jet 10" jointer/planer and I've been using it quite a bit. However, after trying to joint some longer boards (anything over 2'), it seems like no matter how hard I press down on the board on the outfeed table, my boards end up with a very gentle curve in them. In other words, if I set the jointed board on a flat surface, then only the ends of the board touch the surface, and I can see daylight under the middle of the board. If I then go and joint it again...same thing.

Is this just a technique issue or is something in the jointer not quite aligned? I'm trying to think what could be out of line that would cause this issue.

What I usually do for jointing is keep pressure on the board as it goes over the cutters while pushing it from the end, and then once it is on the outfeed table, I just use pressure on the outfeed table to move the rest of the board along.

Thanks for any help.


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## woodnthings (Jan 24, 2009)

*Have you seen this thread?*

http://www.woodworkingtalk.com/f2/jointer-technique-24042/

Also I don't muscle a board through the jointer, rather let it feed at a rate that the machine sounds "happy" with. The cut is less than 1/16" usually 1/32" and the feed rate is even. I change hands as I feed hand over hand until the end. I use a push block that applies pressure down and forward at the same time. After enough surface is on the outfeed table I concentrate more downward pressure there, but still feed at the same rate. The foam backed blocks are good and you can make your own. The last thing you want is for your hands to slip forward while feeding. And feeding the last few inches is the most dangerous, watch where you fingers are, better yet use the push block. :thumbsup: bill
BTW setting up the jointer is rather complex for the inexperienced. There are some good you tube videos.


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## JMC'sLT30 (Oct 26, 2010)

At first instinct beelzerob I would think that your knives would be set a tad high.


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## H. A. S. (Sep 23, 2010)

Try feeding the stock using only the 'weight' of the stock. Push it from right, to outfeed with no downward pressure. Those cutters will find their own plane..


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## GeorgeC (Jul 30, 2008)

As described above you do not want to put pressure only on the outfeed or infeed side. Keep it even and as light as practicable. Also if you are making multiply passes, switch ends for each pass. Make sure the last pass if very light and down grain.


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## cabinetman (Jul 5, 2007)

This site may be of some help.












 







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## JMC'sLT30 (Oct 26, 2010)

This link may be helpful also. http://www.newwoodworker.com/jntrprobfxs.html


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## TimPa (Jan 27, 2010)

i'm with bill on operation and outfeed pressure. realize that the stock that has passed over the knives and is now over the outfeed table is flatter than the stock over the infeed table, and should be kept in contact with the outfeed table as the cut progresses. if you were to apply even pressure, or worse more pressure, on the infeed side at his time, you will seriously hamper your chances at a straight board. however, it sounds like your set-up is off. i suspect knife height (sb ~.002" above outfeed table) or infeed table alignment. it need to be parallel to outfeed.


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## beelzerob (May 2, 2010)

Thank you all for the great input. On a whim I decided to check/adjust the knives. I have no idea how high "too high" was on this thing, but they seemed a tad high to me. All I have is a little flat box of aluminum as my jointer knife guide...it's *very* imprecise. Basically I roll the knives back and forth and see how much it moves the little box, which is sitting on the outfeed table. So I know the knives are higher than the outfeed table, just not by how much.

I adjusted the knives down because I thought maybe they were too high as suggested. Wow, did I learn I was wrong! They were definitely too low after that, as boards I was jointing began see-sawing on the edge of the outfeed table. So, back to adjusting the knives (guess what took up almost all of my free time last night!). I put them about back where they were. Much better jointing this time.

I'm not sure if I've made any improvement yet or if I just messed things up. The infeed table is very iffy as far as alignment. When you loosen the lock knobs and start turning the knob to lower the table, you can actually see it shimmy left and right as it comes down. So I used a straight edge and tried to adjust it to straight before locking it down.

I've already started the murmuring to my wife about needing a new (or used) jointer. We love what we have because 1) it's 10" wide, 2) it planes too, and 3) for our level of woodworking skill, it has met the need. As it usually the case, #3 is the issue. We're finally getting better so things like precision and useability are becoming larger factors.

Again, thanks for all the help. The videos and links were useful, but I will say that this Jet jointer/planer is an altogether different beast.


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## TimPa (Jan 27, 2010)

beelzerob said:


> Thank you all for the great input. On a whim I decided to check/adjust the knives. I have no idea how high "too high" was on this thing, but they seemed a tad high to me. All I have is a little flat box of aluminum as my jointer knife guide...it's *very* imprecise. Basically I roll the knives back and forth and see how much it moves the little box, which is sitting on the outfeed table. So I know the knives are higher than the outfeed table, just not by how much.
> 
> I adjusted the knives down because I thought maybe they were too high as suggested. Wow, did I learn I was wrong! They were definitely too low after that, as boards I was jointing began see-sawing on the edge of the outfeed table. So, back to adjusting the knives (guess what took up almost all of my free time last night!). I put them about back where they were. Much better jointing this time.
> 
> ...


 you may find that there are jib adjustments to tighten the play out on the infeed up and down travel. if not a teardown and cleaning may reveal something to you. it sounds like it would be worth the effort. wow, a 10 incher!


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## beelzerob (May 2, 2010)

TimPa said:


> wow, a 10 incher!


Heh...ya, that was a large part of the draw of getting it. We needed a jointer and a planer, and so for the cost of getting a good new 6" jointer, we got both.

However, Jet made some interesting and sometimes unfortunate design choices, but no doubt to keep the thing affordable. The tables are all aluminum, which is doubly annoying. First, I can't use my nifty magnetic featherboards on the thing. Grumble. Second, the aluminum all has grooving in it, in arcs surrounding the cutting area. So it's like the infeed and outfeed table make one big vinyl record. The obvious downside to this is that wood doesn't tend to like being pushed across grooves. Once I get a board across both tables, it is a serious challenge to keep it moving. I've applied wax to try and fill in some of the grooves, and I think it might have helped for a little bit.

The fence is also aluminum, and *fairly* rigid.

For the very small hobby type work we do (my whole existence at this point is to provide prepared boards for my wife's scroll saw), this thing has worked well enough, and the 10" capacity has been really useful, as that's usually right in the range of size she needs, so no having to glue up boards. 

But the problems began when I tried jointing a board a little over 3' long. So I think we may be limited to maybe 1 1/2' of reliable jointing. I dunno yet.

Still glad we got it though...but I'm starting to wonder how much better a more sturdy iron jointer would be, even if it is only 6".


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## loosebolt (Feb 2, 2011)

years ago i had the chance to use a makita planer/jointer2030 combo

i was impressed with its performance for a machine of this type. I've herd that they can be purchased for a reasonable price if you can find one.


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