Half-lap joints are one of the mainstays of the Arts & Crafts style. They are used extensively in the grid work of contemporary Arts & Crafts furniture and picture frames. In this post I’ll show you how I make picture frames using half lap joints.
I begin by milling the frame stock. I mill two rails (short pieces) and two stiles (long pieces). I also need two extra stiles because an extra stile can replace a ruined rail or stile. These extras enable me to make practice or warm-up chamfers before I start working on my primary stock. For this reason, I recommend that at least one of your spare stiles be the same species that you are using for the frames. If, for example, you practice on poplar and then move to quarter-sawn oak, you’re going to experience a big difference in the amount of force necessary to use the block plane. Finally, the extra stiles can serve as spacers when you are cutting the lap joints with your table saw.
Next, I plane the edges and faces of my stock in preparation for finishing. This step may seem out of order, but it is not. You don’t want to cut your chamfers first and then prepare the boards for finishing because this order will put your chamfers out of symmetrical alignment.
After you finish dressing your edges, it is important that you check the width of all pieces for consistency. For this process to work, the frame stock widths should be as consistent as possible—the closer the better (within one to three thousandths of an inch of one another). If they’re not, then make additional plane passes until they are consistent.
After the edges and faces are done, it’s time to cut the chamfers. For an in-depth discussion on cutting chamfers see my Chamfering for Arts & Furniture post.
For picture frames, when completing your chamfers,do not slice-cut the ends of your stock as this will make your frame stocks inconsistent in length, which will negatively affect your half-lap joint placement.
With the chamfers complete, it’s time to cut the half-lap joints. I prefer to lay out my half-lap joints in a revolving pattern; in other words, alternating the joints in a circular pattern around the frame. Thus, to lay these out properly, you’ll start the first end with a joint and then flip the board lengthwise and lay out the joint at the other end on the opposite face. The layout line closest to the end of each piece of stock is 1 1/8” from that end. The second cut will be determined by the table saw setup, but as a second check, you can calculate it as the width of your boards plus 1 1/8” and then lay it out.
Next, I cut the frame’s half-lap joints on the table saw with a dado blade. My first cut establishes the edge of the half-lap joint closest to the end of the frame stock, and the second cut establishes the width of the half-lap joint. Subsequent cuts remove the material between the two cuts.
I use my rip fence and a two-spacer system to determine the location of the first and second cuts and eliminate measurement and layout errors. This negates having to lay out eight joints. I also employ a hold-down mechanism to ensure consistent downward pressure. This greatly enhances the probability of producing dado cuts with a consistent depth, which is essential to getting perfectly seated half-lap joints with the table saw.
I use two spacers for three purposes with my rip fence to ensure consistent, tight half-lap joints. The first spacer, a “dado spacer,” is necessary to compensate for the width of the dados. The second spacer is created from a piece of extra frame stock. Care should be taken to ensure it is the same width as the frame stock. I label it “anti-kick back spacer” in the pictures and it creates a gap between the frame piece being cut and the rip fence to ensure that kickback does not occur. The anti-kickback spacer also serves to ensure your second dado cut is positioned correctly at the precise width of your rails and stiles.
Install your dado blade according to the manufacturer’s instructions. The critical step in setting up the dado blade is its height, which determines the depth of the half-lap joint. This height needs to be precisely half the thickness of the frame stock. I use calibers to determine this measurement, and then set the height as close as possible to this measurement. I make test cuts and confirm with the calibers that the setting is acceptable—plus/minus a few thousandths of an inch is close enough.
With the dado blade set up, cut a dado in a piece of scrap lumber and make a spacer that fits snug in the dado. I usually set up my dado for an approximately 3/4” cut. Then I can grab a lumber-stacking sticker and trim it with a hand plane or a couple of light passes on the jointer to make this spacer.
To set up the tablesaw fence and spacers, use a sharp pencil to lay out the first dado cut at 1 1/8″ from the end of the stock. Next, set the frame stock in the cross-cut sled or sliding table with the blade aligned to cut on this mark and remove the material between the line and center of the half-lap joint. Now secure the frame stock with a hold-down device. Finally, place the anti-kick back spacer against the end of the frame stock, slide the rip fence up to the spacers, insert a backer board to prevent tear-out, and secure it place.
To make your first cut, remove the anti-kick back spacer, turn on your table saw, and push the piece through the blade. To make the second cut, without moving your fence, place only the dado spacer against the fence, and then place your frame stock in your cross-cut sled (with a backer board) against the Dado spacer and engage your hold-down mechanism. Again, remove the spacer, turn on your table saw, and make the cut.
If you have any reason to believe there are inconsistencies in your frame stock’s width, then you can place a shim between the dado spacer and frame to decrease the width of your half-lap joint. This will allow you to fit the frame pieces individually by making passes on the frame edges with a hand plane until your joint fits. Remember to alternate plane passes between both edges to minimize the impact on the symmetry of your chamfered ends.
After the first and second dado cuts are made, make additional cuts as required to remove material between the two cuts. Now you’re ready to test fit your joints.
When you’re satisfied with the fit of your joints, it’s safe to complete the chamfers. The only step remaining is taking one or two passes with your block plane on the ends of the frame stock.
Now you’re ready to glue the frames. This can be a little tricky with the revolving pattern of half-lap joints. But with a little experience, you can master this challenge. In the interim, you can glue and clamp the two halves of the frame and then glue and clamp the two halts together.
With the frame assembled, it’s time to cut the rabbit that will hold your glass, mat, picture, and backboard. The size depends on what and how you’re framing. For this frame, I routed a 5/8” x 5/8” rabbit. A design consideration when deciding the size of your rabbit is how thick the line will be that surrounds your framed object (on the interior of the frame) as a result of your rabbit size.
After you’ve decided on the size of your rabbit, you’re ready to cut it. I prefer to use a router table because I feel it gives me more control over the process, but if you like, you can use a hand-held router. Before cutting, ensure you understand the proper direction to move the frame or router. A note of caution on this step, instead of making one bold cut on the router table, I prefer several small cuts as this helps prevent tear-out on the edge of the rabbet lip. Tear-out will show up as a very visible gap between the framed object and the edge of the rabbet lip, which is visible when viewing the frame from the front.
Finally, chisel out the corners. As you get near the bottom of your rabbit, be careful not to make forceful cuts going with the grain or you may split the lip of the frame.
That’s it! Your frame is now complete. You’re ready to apply the finish and install your keepsake picture.
In the unlikely event you have some gaps in your half-lap joints, read Making Wedges to Repair Half-lap Joints.