Jointing long boards & getting

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Forum topic by opalko posted 07-26-2011 01:54 AM 6690 views 0 times favorited 14 replies Add to Favorites Watch
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148 posts in 3211 days

07-26-2011 01:54 AM

Topic tags/keywords: jointer

I am trying to joint the edge of some 85” long white oak boards on my jointer. The jointer has a 36” bed. I have all the roller stands lined up (4) to keep the boards flat on the table. I have successfully jointed the edge of 3 boards (I’m making a tabletop). However the one edge of the center board is giving me fits. I cannot get it dead straight. I continue to get a curve inwards torwards the center of the board. In other words, when laid flat to the next board I get a 1/8” – 3/16” gap in the center, while the boards ends touch. I should note there is a largish knot in the center – could this be the problem? I have even gone so far as to run the board back throught the tablesaw, joint the edge again to clean it up – and the same result? Picture of the gap between the boards although the knot and the spots are not that dark/big.. I think the photo is magnifying it. No, it’s not the board next to it. The gap occurs no matter what board I lie next to it. Should I give up on my itty bitty jointer and save up for a 76 incher?? I’m ready to quit this project!

14 replies so far

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17718 posts in 3182 days

#1 posted 07-26-2011 02:03 AM

Opalko i wouldnt worry too much about that gap, some people even prefer it, ive heard of it called a spring joint. IMO if you can clamp it and there is no gap you are good to go just make sure you dont starve it on glue. BTW .. if you want to get rid of your jointer ill clean a spot in the shop for it, feed it three times a day, and keep it good cpmpany too.

-- Its not a crack, its a casting imperfection.

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10477 posts in 3823 days

#2 posted 07-26-2011 03:08 AM

Getting any 86” board straight on any jointer (much less a 36” one) is
tricky. Sprung jointing is an effective dodge to the problem of
perfection, since it is preferable to the opposite issue of a joint that
pulls apart at the ends… which, incidentally, is not uncommon to
see in antique furniture with exposed end grain and long joints.

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10477 posts in 3823 days

#3 posted 07-26-2011 03:16 AM

And yes, the knot is likely part of the cause of the problem you are having.

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101 posts in 3389 days

#4 posted 07-26-2011 03:23 AM

You could always use a handplane to bring the ends of the board down a little. They excel at things like that!

View buckles's profile


24 posts in 2717 days

#5 posted 07-26-2011 03:32 AM

Just a suggestion, run it through again, turn it over and join the other edge, repeat, repeat. If you can get one edge straight, run it through the TS and cut the curve out.

What you do to one side of a board you must do the the other. Rule # 1 in high end woodworking.

Do not glue it up and clamp the gap shut, it will split apart later. It is a matter of when, not if.

-- Politicians are like diapers. They need to be changed for the same reasons.

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1586 posts in 3936 days

#6 posted 07-26-2011 03:46 AM

I only have a 4” jointer with 28” of infeed & outfeed, yet, I have many times successfully jointed and glued boards as long as 100 inches.

I use Rockler’s heavy-duty “flip top” roller stand on the outfeed end as it is heavy, unmovable, and rock steady. I zero the roller stand flat with the outfeed table using a Veritas 50” aluminum straight edge that is guaranteed straight within .003” over it’s length. I set a medium duty roller stand on the infeed side, again using the Veritas straight edge.

That said, I like a spring joint and will often take a #5 hand plane, set to remove just a few thousandths, to the machine jointed edge to correct any flaws and to create a slight amount of spring.

-- "Heaven is North of the Bridge"

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61 posts in 3145 days

#7 posted 07-27-2011 03:45 AM

Like Loren said it is the knot that’s the problem, a curious choice. You can lay both boards flat, good sides up on a table/bench with both ends parallel to each other. Use a router with a half inch spiral cutter, or mortise bit. Gap the boards 7/16ths apart and run the router bit between the two at the same time using a straight edge to guide the router base. This will give mirrored edges and a tight glue up. Does that make any sense?

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13551 posts in 2868 days

#8 posted 07-27-2011 02:14 PM

I always handplane the middle of long boards to get a bit of a “sprung”. It takes a little practice on the “takeoff” and “landing” but it makes for a solid glue-up. Good luck!

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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4541 posts in 3250 days

#9 posted 07-27-2011 06:33 PM

A 3/16” gap may be a little much for a spring joint. On an 85” board I would look for a gap of about half that. You can probably get there with a handplane.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View opalko's profile


148 posts in 3211 days

#10 posted 07-27-2011 09:49 PM

Thanks for the tips. I ran both pieces through the jointer again, taking shallower cuts and was able to get rid of the gap.

Curious about folks concerned about the knot. I do not have a furniture grade hardwood supplier within at least 150+ miles of me, which makes “picking and choosing” to get FAS type pieces nearly impossible. I wish I had more pieces to choose from that were awesome looking but I don’t, and I’m in a time crunch to get the table made. The problem now is that I’ve lost a good enough cleaning up these pieces off the width of the entire top so that I’m now down to around 33” for the top. I need 3” more to get a 36” top….arrrggggh!


View Ritty's profile


63 posts in 2972 days

#11 posted 07-27-2011 10:16 PM

put that board that given u pronlems on the outside so theres no joint on that edge or brake out the handplane

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14 posts in 2701 days

#12 posted 07-27-2011 11:50 PM

In the past before I got my long bed jointer, I use to use a 1/4” piece of 2” wide steel bar stock to use as a straight edge to rip long straight edges on boards. Just measure the off set from the blade to the edge of the saw plate and move the straight edge over that amount and clamp both ends of the bar stock straight edge and go ahead and rip. It is amazing how true and straight the rip will be. the saw cut is pretty smooth if you use a good multi tooth blade. I use the 40 tooth 6” blade for my little PC hand circular saw.

-- "Lord, keep your arm around my shoulders and your hand firmly over my mouth!!"

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4492 posts in 3918 days

#13 posted 07-28-2011 12:14 AM

The knot could be giving you fits, but I would expect there to be bow – so a gap in the center on one side and at the ends on the other side. But since your set-up seems to work for the other boards, can you swap out this board for another – or get another from the lumber distributor.

Another possibility -
Find someone with a larger jointer an ask to borrow or rent some time for an hour or so.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View Howie's profile


2656 posts in 3098 days

#14 posted 07-28-2011 01:22 AM

Ever since I bought an Incra LS-25 for my router table, my jointer gathers dust when it comes to edge jointing.
I would think that bisquits and clamping would solve this problem for you. Just my $.02

-- Life is good.

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