How to Create Gap-Free Joints
Now it’s time to glue up the parts making the table top and shelf, but achieving gap-free results can be harder than it looks. If you’re new to this operation, be patient with yourself. Even experienced cabinetmakers sometimes face challenges creating gap-free edge glued joints.
Start by putting the table top and shelf parts together, side by side, to see how the joints look without glue and without clamping pressure. Ideally the three or four or five boards you’re using to get the width of parts you need fit together gap-free (or close to it) under nothing more than hand pressure. If that’s not the case, flip the parts around and try different joints mating up. Sometimes specific edges can get along better with some neighbours than others. Swapping things around is sometimes enough to make small gaps go away. If not, go back to the jointer and work on those edges that seem to have irregular areas. Trial and error is the best way to get tight joints, and tight joints are key to a table top that looks great. Don’t settle for any gaps in such a prominent surface.
If your table top lumber wasn’t originally sawn for vertical-grain or quartersawn grain orientation (as explained in a previous video), glue table top and shelf boards together alternating the growth ring cups upwards and downwards. See the video up next.
You’ll get best results if you glue up the tabletop and shelves in two halves, while the wood is still 1/8” or so thicker than required. Since most workshop thickness planers aren’t wide enough to handle a 22” wide table top, plane each half of the tabletop separately. You might as well use the capability of your thickness planer to level up what joints you can. When the halves of the top and shelf are planed down to final thickness, finish up by gluing the planed halves together. This leaves just one, central joint to level up and smooth using a scraper and belt sander. Although the overall shelf eventually needs to be about 19 1/4” wide, glue up the shelf blanks to a width wider than 16 1/2” for now, then set it aside. In the same way, leave the top at least 1/2” wider than the finished width of 22”. You’ll see why in a minute.
With the table top planed to final thickness, cut it to final length only. Leave it wider than needed for now. Ripping the table top to final width of 22” is easy on any tablesaw, but trimming the tabletop to length is tricky because it’s so wide and the quality of the cut matters because the end-grain edges remain so visible. You can see what I mean in the photo of the complete table corner to the right. You really need some nice, smooth results. My tablesaw was just barely wide enough to crosscut the tabletop this way, but the surface still had saw marks. You can certainly clean these up with a carefully wielded belt sander spinning an 80-grit abrasive, but there is another way.
Don’t have a tablesaw wide enough for the job? You could trim the ends of the table top using a hand-held circular saw following a clamped wooden guide strip, but saw marks and splintering could be a problem. The good news is that fixing the rough-edge flaw is where a trick involving a router and something called a flush-trim router bit comes in. That’s what’s up next. It’s a powerful technique you’ll use over and over again for other projects.
Before going on to the next phase you should have:
- Table top and main shelf parts glued and ready to trim to length but still wider than needed.