jointing before glue-up?

[Admiral]

As noted, test the edges coming off the TS, and if not just right, then to the jointer; that being said i generally take a #7 plane to the edge, more accurate.

[Hank Knight]

Is there a specific area of concern?  straightness, squareness or smoothness?

When I do the "light test" with edges off my saw or my joiner, I always find light passing through the joint. It may not be much, but it's enough to tell me that the joint surfaces are not a perfect match. I believe a knife cut edge (I.E., with a plane iron) leaves a cleaner surface than an edge cut with either my table saw or my jointer. Michalemouse mentioned burning (with the tablesaw) and I think there is always a modest amount of scalloping with a powered jointer. I strive for clean, perfectly matched surfaces for the glue joint (maybe overkill, but it works for me) and my hand planes give me this. I don't use "spring joints" that I need to close with clamp pressure. If I get a perfect match along the entire length of the joint, I'm happy. A perfectly matched joint requires only modest clamp pressure. I have some pieces with large solid wood panels I've made over the years using this technique and all of them have held up perfectly. None of them have opened up on the ends (which is the rationale for spring joints). I don't think you can beat clean cut, perfectly matched mating surfaces for a good glue joint. They take a little extra effort, which can be tedious and infuriating at times, but they are worth it in the long run.

[Derek Cohen]

Here is a Jarrah board I ripped on my Hammer K3 slider using a combination blade (nothing special) ...




A close up ...



It is three boards, not one ...



A slider can rip an edge joint ready for gluing. The reason is that the board slides pass the blade, minimising any deflection.

Regards from Perth

Derek

[Hank Knight]

Here is a Jarrah board I ripped on my Hammer K3 slider using a combination blade (nothing special) ...



Derek

That is a beautiful match, Derek! I don't think I've ever seen better.

[K. L. McReynolds]

I use glue joint saw blades on my TS and a digital angle gauge to set the angle of the saw. I also have a long jointer and a planer. I just had to resurface some pine I used about 20 years ago to make a cabinet into pieces to make 14" square plant stands. My planer is 12". Used the TS to rip the 14" pieces, surface, and reglue. No lines or at least none so obvious I felt I needed to joint the edges.

Point? Tool quality and set up is the key.

[KyleD]

A properly maintained and adjusted jointer and proper jointing technique should leave you glue ready edges. Same goes for a table saw- sharp and perpendicular blade, stiff and parallel fence, and proper feeding technique. A jointer and table saw are often used in combination in my shop. While a table saw gives a glue ready edge it is only as straight as the board edge that is referenced against the fence. This is where the jointer comes in. Get your first straight edge on the jointer then use that edge against the fence to get the other straight and parallel edge on a table saw.

[jcousins2]

Going too fast on a jointer will create scallops-no matter how sharp the blades. Just go slow and steady.

[Gary G™]

Yes, check your jointer.

I never glue up off the table saw, simply because the cuts are never perfect.

I try to have the tools dialed in so that the surfaces look good off the jointer or planer, and the edges of my table saw cuts are also clean.
But it depends on how closely you need to look -- the rotary cutting from a jointer or planer can sometimes be seen with a raking light, so for a truly finished surface, I'd either plane or sand afterwards.

I don't know that this irregularity would affect a glue joint.  But I don't think the edge off the table saw is any worse.
So I was wondering why I sometimes see advice to do a final pass on jointer before glue up.

Matt

I really believe ‘it depends’—I’ve done glue ups off the jointer, tablesaw and planer—gang-running boards through the planer on edge.

I can get a real clean cut off the Unisaw with a quality blade.
I expect the advice might be geared more to contractor saws and cheap blades.
However, as noted, dull jointer blades or going too fast can produce poor results.

If they’re square, true and plumb with smooth surfaces, the glue-up should be fine.
I’ll put my Starrett 4’ straight edge on it and, if it touches the entire edge without anomalies, I don’t care which tool produced it.