Tools for Fine-Tuning Joints
Take your joints from "not quite" to "super tight" using these basic tools and methods.
With a shoulder plane, you can smooth rabbets right up to the shoulder for cleaner edges and stronger glue joint.
Thin enough to see through
Machines cut joints fast, but not always accurately. That's the time to bring in hand tools because sanding blocks, chisels, and planes remove wood in thousandths of an inch for a snug joint.
If you don't have a block plane or shoulder plane, don't rush out and buy them—yet. Start simple with a sanding block you can make for pennies using scraps, sandpaper, and spray-adhesive. Then add a good set of bevel-edge bench chisels. As your joinery skills improve, save time by supplementing your sanding blocks with well-honed block and shoulder planes.
Sanding blocks: slow but simple
Uses: Reduce tenon thickness by sanding the cheeks, and make the shoulders even with each other as in the photo; smooth scoring from tablesaw-cut rabbets or dadoes or stub-tenon grooves for cleaner edges and a stronger glue joint; and adjust half-lap depths to make parts flush. For a curved sanding block to fine-tune coped ends on molding, wrap sand-paper around dowels of different sizes.
Flatten saw blade dadoes
Success secrets: Match the grit to the amount of stock to remove-start at 80 grit for removing deep score lines; 120 grit works great for minor tenon corrections. Then match the block size to the job. For example, plane a scrap block to the thickness of your dado widths; then mount sandpaper to the edge for a sanding block that works the entire dado with each pass, see photo. Choose hardwood sanding-block stock that will hold a crisp edge, and attach sandpaper to only one surface, not adjoining faces or edges. That lets you adjust one dimension of a joint without affecting the others, see Slide 3. Abrasives on small sanding blocks wear in a hurry, so change paper frequently.
Chisels: The joint-maker's edge
Uses: Trim smooth walls and square ends on drilled mortises, see photo; on hand-cut dovetails, slice straight lines for clean joints and shave pins to fit the tails; square stopped rabbets, see Slide 6.
Success secrets: Hone the bevel and flatten the back for an edge sharp enough to shave the hairs on your arm.
A chisel follows grain as it cuts. For paring cuts with the grain, cut from the opposite direction if you begin to feel the chisel plunge down into the wood. Where that's not an option, hold the chisel perpendicular to the grain and tap it to make 1/16" stop cuts. Then remove the wood between the stops.
Use the widest chisel that fits the joint area you're cutting. To trim the walls of a 2"-wide mortise, for example, two cuts with a 1" or
1 1/2" chisel leave cleaner, straighter lines than four or five cuts with a 1/2"-wide chisel.
Clean up a stopped rabbet
Straight router bits work fast, but they don't square corners. A sharp chisel completes the rabbet in two quick cuts.
Block planes: Perfection comes .002" at a time
Uses: Flush-trim edges on parts joined with a machined dovetail; clean up sawn edges to be glued; chamfer tenon ends and panel edges for easy insertion, see photo; clean up cross-grain cuts, such as mitered ends on hand-sawn frame pieces; trim ends or edges that stand proud of an adjacent workpiece; make drawer side edges flush with the drawer front.
Look for consistent curls
Passes on the edge of a scrap block should produce light curls of even thickness from side to side.
Success secrets: Check the plane sole for flatness. The best plane works only as well as the sharpness of the blade. (For a video on how to hone a razor-sharp edge using sandpaper, go to woodmagazine.com/sharpeningvid.) Test the plane's cutting depth on scrap until each pass takes a consistent, translucently thin curl, see photo. Before tackling a workpiece, practice controlling the plane balanced on the edge or end of a 1/2"-thick practice scrap.
Shoulder planes: Tools that work lying down
Uses: With blades that cut a hair wider than the plane body, these specialized planes straighten tenon shoulders and shave tenon cheeks with ease. Other uses include smoothing dado, rabbet, and groove bottoms, as shown in photos.
Success secrets: You'll often plane cross-grain with this tool, making a razor-sharp blade essential for success. Center the blade on the plane body, see top photo. Then adjust the cutting depth to make shallow passes with no tear-out, see bottom photo. Because it cuts faster than a sanding block, stop frequently to test-fit parts.
Shoulder plane. Medium shoulder plane no. 05P41.01 (with a hard A2 steel blade for less sharpening), Lee Valley Tools, leevalley.com.
Block plane. Veritas Apron Plane no. 05P27.02, Lee Valley Tools.