can't get a straight edge.....frustration

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Forum topic by Sorethumbs posted 03-18-2013 09:29 PM 2899 views 0 times favorited 14 replies Add to Favorites Watch
View Sorethumbs's profile


38 posts in 2646 days

03-18-2013 09:29 PM

I can’t get a stright edge. I’m attempting to edge glue a large panel for a table top. No matter what I do I’m ending up with a gap in the center of the boards with the ends tight. In other words the edge of the board is concave, I’m at my wits end!!

No matter how many times i run it through the jointer…same thing…gap between the boards in the center.

These are large boards, 4/4, rough cut pine, 10” wide, 6’ long. My jointer has a bed that’s aprox. 42 inches total length. Are these boards just to dang big for my jointer or what?

I have sucessfully made smaller glue-ups before for things like raised panel cabinet doors with my jointer. When I’ve done that the entire length of the boards join tight, so I can’t figure out whats wrong!

14 replies so far

View Logan Windram's profile

Logan Windram

346 posts in 2460 days

#1 posted 03-18-2013 09:54 PM

Sounds like you have the making of an unintended Spring Joint…

6ft long is a long piece of stock to joint… not that it can’t be done, but is it just a cumbersome process on a jointer with a bed less than its total width.

When you clamp their pieces, do they come together flush and square, even with the concave?

View higtron's profile


235 posts in 2675 days

#2 posted 03-18-2013 10:23 PM

It could either be your jointer isn’t coplaner or your board is reaction wood, have you ever ripped a board on your tablesaw and the kerf started to close up or, widen.

-- A friend will help you move, a good friend will help you move a body

View pintodeluxe's profile


5658 posts in 2811 days

#3 posted 03-18-2013 10:27 PM

If the gap is small, it can likely be closed with clamps. Give dry clamping a try and see what it looks like. A gap of 1/8” or less is no big deal. Just leave your top oversized, and trim it after glueup.
Otherwise, try an outfeed roller, set even with the outfeed table of your jointer.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View crank49's profile


4030 posts in 2969 days

#4 posted 03-18-2013 10:28 PM

Apply extra pressure to the front of the workpiece at the beginning of the feed and then go light in the middle and finally extra pressure to the rear as you finish the feed.
When I started using my jointer I tried to keep all the pressures and feed rates even as possible and I had the concave problem also. Tried the variable pressure thing and the problem got better.
Also, an out feed roller support set ever so slightly higher than the end of the out feed table might help with the long boards.

View lew's profile


12060 posts in 3753 days

#5 posted 03-19-2013 12:21 AM

Did you check the adjustment of the outfeed table? This will happen if the table is slightly BELOW the level of the blades.
Here’s a link to the correct position of the outfeed table-

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Tony_S's profile


867 posts in 3081 days

#6 posted 03-19-2013 01:21 AM

I would say your out-feed table is too low. If it is, as well as making the cut concave, you’ll also get a ‘snipe’ at the end of the board as it comes off the in-feed table.

-- It is the mark of an educated mind to be able to entertain a thought without accepting it. Aristotle

View ajosephg's profile


1880 posts in 3559 days

#7 posted 03-19-2013 09:33 AM

I use a Freud glue line rip blade for my glue ups, and the boards are perfectly straight and smooth.

-- Joe

View popmandude's profile


109 posts in 3018 days

#8 posted 03-19-2013 09:43 AM

+1 what joe said. Jointer is better suited for squaring. Table saw for strait line, or making parallel.

View Sorethumbs's profile


38 posts in 2646 days

#9 posted 03-19-2013 02:08 PM

A lot of good suggestions, thanks.

When using smaller stock on this jointer things come out perfect, no snipe. I painstakingly set the blades, I don’t think the blades are higher than the outfeed table.

My normal method for panel glue-ups is to joint one edge on the jointer. Then rip to parallel on the table saw and glue. Done. It just isn’t working with these big boards. I tried an outfeed roller too, still concave. I must not be able to achive the correct downward pressure when the ends of the board are over the jointer blades. I normally strive for percise edge mating before glueing. I guess his project might need more muscle than finesse. That or a jointer with a extra long bed…I wish.

View Craftsman on the lake's profile

Craftsman on the lake

2790 posts in 3436 days

#10 posted 03-19-2013 02:13 PM

It’s also possible that your jointer fence isn’t square. Flip one board over and see if the joint changes. If so then the skewed edge might be the culprit. Outside chance. Just another possibility to check.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View Miles King's profile

Miles King

28 posts in 2690 days

#11 posted 03-20-2013 11:29 AM

Similar to what crank49 said. If jointer adjustments are within spec then what usually remains is technique. Here is where class instructions, in my opinion, are most helpful: the instructor noticed that my edge jointing technique of applying pressure to the board as it moved over the knives would produce an out of straight joint. He helped my correct the procedure and I’ve not experienced that problem again.

-- Miles

View Sorethumbs's profile


38 posts in 2646 days

#12 posted 03-20-2013 02:19 PM

I try (and normally do) apply pressure to the board on the outfeed bed only, however, with a heavy 6 foot board on a somewhat small jointer table I realized quickly that things can’t be quite so perfect.

I’m used to a no gap glue-up. When those gaps are there it makes me want to whip my hat on the floor, stomp on it, and swear like a 2-bit whore. I can’t help myself.

View Handgrenade's profile


6 posts in 2632 days

#13 posted 03-20-2013 02:38 PM

Another method you might consider is attach the board to a piece of mdf or plywood with a factory edge. Then run it through the table saw with the factory edge against the fence. Or, you could use a router with pattern bit run against the factory edge.

View Bill White's profile

Bill White

4930 posts in 3959 days

#14 posted 03-20-2013 02:57 PM

+2 for Joe.
I don’t have a jointer in my home shop. A well tuned TS with a glue line ripper is what I use.


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