Joining 8/4 boards along long glue joints

[alex grams]

It seems I always have a challenge with longer boards that are thicker when I am gluing them up for a tabletop. I have a G0634Z combination planer/jointer, which admittedly has a shorter outfeed bed than most jointers. But getting a 6'+ length straight edge for full continuous contact on an 8' board is always tough, and it is thick enoguh that you can really clamp it and push the joint together that well.

Thoughts on ways to get a good straight edge? My best bet lately has been to take a long sheet of plywood, use the tablesaw to get a very good straight edge on it, then use that with a router to make the final cut on the edge, and then I just have to touch it up with a scraper/sander/hand plane (but even then, when it is mesquite, you won't be hand planing that wood....)

Thanks in advance.

[Rod Sheridan]

Hi Alex, when I'm doing long boards I add a 12" table extension to my J/P, perhaps you could try that?

I also often put a glue joint profile on the boards if they're long with the shaper, that may help as well.

Regards, Rod.

[Prashun Patel]

Glue them together as is, then rip the joint and re-glue.

I recently had to do this and the joint was too long for me to do the above comfortably without any wobble.

http://www.sawmillcreek.org/showthread.php?223893-Slab-table-jointing-help&highlight=

In the end, the solution was to use a long jointer plane and the longest plywood straight edge I could muster to test for rock. I used a jointer plane with an edge guide and then planed the pieces while they were sitting flat on horses; so I was planing sideways, using the guide to register off the top side. The weight of the slabs provided good enough mass to provide proper resistance; it was like planing on a bench.

You might try this. It was easier than I thought and probably the most gratifying woodworking experience I've had in the past year.

[Bradley Gray]

I keep a 10' length of steel drip edge in the shop. Straight as the die it was made on and cheap enough to replace when it gets damaged.

[John TenEyck]

You just need to practice more with your jointer. I have an Inca jointer and the whole thing is less than 40" long. I regularly joint stuff 6 - 8 ft long on it, including 6/4 and 8/4 stock for panel glue-ups. It just takes practice to get a true, straight edge. I admit I have resorted to the straight edge + router for some really long, really heavy pieces, but that's the exception. I've also resorted to using a glue-line rip blade on occasion and it does a really good job, but again, that's the exception.

John

[Jamie Buxton]

My jointer is the same length as yours. I edge-joint boards that are 6' long without any outboard assistance. When I need to joint something like a 10' board, I use a roller stand on the outfeed. I put it two feet or so away from the end of the jointer. I use a 4' straightedge resting on the outfeed table to adjust the height of the stand.

When you're jointing a long board, the tuning of the jointer becomes more critical. The knives need to be flush with the outfeed table, and the infeed table needs to be parallel to the outfeed table. If those things aren't right, the jointed edge comes out curved. That is, it is the adjustment of the jointer, not the length of the beds, which causes trouble.

[Scott T Smith]

On the big stuff I use a router with a guide.

SMC member Maurice Ungaro and I are building a couple of Roubo workbenches with some 3-1/4" thick quartersawn oak slabs for the tops. Here is a photo of Maurice using a router with a 4" long, 1/2" diameter spiral end mill to edge joint the two slabs for gluing.

Even though they were not very long, the shear mass and weight of the slabs (about 100 lbs each for Maurice's slabs, and 200 lbs each for mine) makes precise alignment against a jointer fence very difficult.

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Here is the glued up slab after surfacing:

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[Prashun Patel]

Great Scott! What bit's in your router? That thing looks 3" long.

[Rod Sheridan]

Great Scott! What bit's in your router? That thing looks 3" long.

Prashun, OP indicated a 4 inch long bit.......Rod.

[Scott T Smith]

Great Scott! What bit's in your router? That thing looks 3" long.

Prashun, I use this end mill from McMaster: http://www.mcmaster.com/#2883A35.

6" overall length with a 4" cutting surface. Since it is a 1/2" shank bit it chucks right up in the router collet.

[Bill Huber]

I use a Freud 24 tooth glue line rip blade on my table saw and then do the glue up. I have never done a 6' board but I have done some 5' boards for a table, they glued up just fine.
You are doing edge to edge or am I just not reading your post right?

[Prashun Patel]

With no flex?
What speed do you use?



This is great to know. Thanks for the tip.

[Scott T Smith]

With no flex?
What speed do you use?



This is great to know. Thanks for the tip.

It's a cobalt steel end mill, and pretty rigid. I usually take small cuts per pass (about 1 - 1.5mm) and edge joint one slab from the show side and the other slab from the bottom side in order to allow for any alignment discrepancies with the bit.

I had to make a spacer which I attach to the bottom of my router to raise it up level with the track. It's around 3/16" thick, or thereabouts. I use the Festool Router guide stop adapter #492601 to make the adjustments.

Here is a close up photo of the jointing process.

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[Jeff Duncan]

If you do enough long boards and your jointer is stationary I highly recommend making up some in-feed and out-feed extension tables for it. I did this for my first jointer, a little 6" import. Then made a set for my 16" jointer which I used for years. I've since upgraded to an aftermarket set, just for convenience, but the shop made ones did the trick for years. I was doing a bit longer work, 10'+ when I needed the tables, but if your having trouble on shorter stock they'll certainly help. I don't like rollers or any other support that is not continuous. It's just my person preference as it just doesn't provide as adequate support as a continuous extension.

good luck,
JeffD

[Bill McNiel]

I take a straight edge and circular saw with a quality, carbide tipped rip blade and precut both pieces individually. Then I butt them together and run the saw down the middle of the joint thereby cutting both pieces at once. This produces a "perfect" mirrored joint ready for glue up. It doesn't even matter if the blade is dead on 90 degrees or if the straight edge is dead true. It is simple, easy and results in an invisible joint. I do it all the time with great results.

[Adrian Anguiano]

Catching up on your posts tonight.... I think this is a great excuse for a festool track saw with a long track. OR i suppose tablesaw a long piece of mdf, then use it as a straight edge for a spiral router bit or circ saw.

If you need strong clamping pressure, id use 3/4" pipe clamps. They are stronger than the fancy parallel clamps.