Gary Rogowski makes a deceptively simple mirror frame with tapers, curves and half-lapped joints
Being ‘fairest of them all’ won’t help you with the success of this mirror project. Think instead: planning, precision and pure contrast. Simple half-lapped frames like this one are easy to cut and have plenty of long grain gluing surface for strength. This makes it easy to shape into the frame and still leave plenty of joint area behind. Plan out your frame shape beforehand and just keep all your parts square or rectangular to make joinery and clamping simpler.
White oak (Quercus alba), red oak (Quercus rubra), holly (Ilex spp.)
Cutting the shoulders
It seems like the only tool I cannot cut a half-lap joint on in my `shop is the spindle sander. Two cuts are required, one for the shoulder and one for the cheek. Mark all these shoulder cuts out with a marking gauge, then rough out the cheek on the bandsaw. Make a quick crosscut on the bench close to the shoulder line, about 1.5mm away from it and down to the cheek.
Next I set up the router table with a wide straight bit with its height at half the thickness of my stock. I clamp the fence so the distance to the far end of the bit will give me a cut right at my gauge line. Use a frame member and a backer when making the final shoulder cut. The backer board will help to make a wider package to move across the bit and help to prevent blow-out.
Assembling the frame
Simple frames like this make for some of the more complicated glue-ups because there are so many directions in which to pull. I set the long rails on my pipe clamps first. This raises the assembly off the bench. The short ends go on and then the pipe clamps pull them in tight, but with room for the two C-clamps that pull the cheeks in tight to one another. Practise this assembly once or twice to get the hang of the process and it will go smoothly. Those off-cuts from roughing out on the bandsaw come in handy as clamping pads too under the C-clamps. Once the clamps are in place, check the diagonals of the frame to see that it’s square and use a long clamp on the longer direction to correct it to square. Once the frame has dried, I clean up both faces of the frame with my No.5 jack plane. If the grain is with me and not too difficult, then this job goes quickly. However, if the grain gives me any trouble, a cabinet or card scraper will remove any tear-out issues. Be careful at the joints where the grain changes directions and move into the board changing your cutting direction to minimise tear-out.
Next, mark out the frame stile tapers. Measure at the top and bottom of them for the required set-in, lay a straight edge down and mark out the taper. I cut tapers on the bandsaw freehand as it’s simple and quick – no tablesaw blade spinning close by my hands and it’s easier to push the wood through the bandsaw cut. Stay close to the pencil line to minimise clean up. I plane the cuts with a No.4 or No.5 hand plane being careful not to blow out any end grain at the end of the cut. A simple chamfer cut into the back edge of the rail minimises this issue. Plus I still have the rail shapes to mark and cut. I mark out the curved rail shapes using a bent piece of red oak with clamps in place to hold it while I mark out the shape. I true up the rail cuts with a spokeshave and scraper.
At this point if I’m happy with the shape, it’s time to cut the chamfer on the inside edge. A 45º chamfering bit works great to get the bulk of the work done topside with the router. You will inevitably run into the problem with routers and corners – they don’t fit together very well. The bearing mounted chamfering bit can’t cut into the corner so this has to be finished up by hand. This mason’s mitre, as it’s called, takes some careful work with a chisel. Best to take your time here for a good look.
The rabbet cut is next for the mirror and backer board. I clamp my frame between my vice and bench dogs raising it up to allow the bearing to move freely along. I almost always climb cut the edge of the rabbet first moving right to left on the edge. This eliminates tear-out when I finish the rabbet cut up moving left to right. Make the rabbet deep enough for the mirror thickness and a 3mm or 6mm piece of hardboard behind it to protect the mirror. This will necessitate making a series of 3mm deep cuts to get down to depth. The corners, of course, have to be cleaned up with a chisel. Use a wide chisel to mark out the cut and then chop to depth.
Clean the corners of the frame with a block plane and a bit of sanding. Then it’s time to focus on finishing. If you’ve sanded, you have to raise the grain before finishing. The ebonising finish is water based so raise with a damp rag. Let the fibres dry before sanding them off with a fresh sheet of 180 grit. Do this several times.
My ebonising solution is made of 114ml white vinegar and rusted metal. Of course, a vinegar from the north side of an Umbrian hillside will give a better colour but leave off searching for provenance on the vinegar to others. Use white vinegar and some rusty steel wool. These steel fibres are small enough that they will break down quickly in the acetic acid solution. Put this concoction in a plastic container as the acid fumes will eventually eat away a metal lid on a glass jar. Let it sit for several days, then glove up and wash down the surface of the frame.
I have found with white oak that a new ebonising solution works best for the darkest colour. If the staining is uneven then a tannic acid wash can go over the ebonising to darken it. I use the acid powder found at shops specialising in wine making supplies. Mixed with water it helps to darken the wood. Put on a coat or two, sanding lightly between coats. Also be aware that a coarser surface ebonises better with this approach than a finely sanded one. Sealing off the surface pores reduces the stain’s penetration.
The grain fill is an inert whitish paste mixed with mineral spirits (white spirit). Cut the paste by 1⁄3 with more mineral spirits to make it easier to work with. Mix this well and then paint it on with an old brush. Move the brush in all directions, especially across the grain. Your goal is to get filler down into the pores. Pound it in if you have to with the brush but push it into that open pore structure.
Wait about 15 minutes to let the filler dry and glaze over. Then wipe off the excess filler from the surface, corners and edges with a piece of burlap first to get the most of it off. Keep wiping out the surface until it’s clean.
Pin the joints next and then place your inlay. I mark out each of the corners on the diagonal, find centre on this line and use a scratch awl to place my mark. Drill for a 6mm hole for the inlay first about 3mm deep. Chop these holes out square. Next, drill out for the dowel to pin the joint. A 5mm pin works fine. I don’t drill all the way through the joint but stop just short of the back face. Use a dowel plate to size the dowel so it enters more easily. Instead of hammering it through however, mount the plate on two sticks and use the vice to press them through. This saves everyone the consternation of the hammer blows. Use the hammer
of course if your therapist recommends.
Drive and glue the 5mm pin in and use a drift to put it below the surface of the frame so that the inlay can enter. A steel rod works well for this.
The square plug inlay stock I used is holly. I shoot the edge of the stock on my bench hook to get it to size after bandsawing it close. I chamfer the end of the inlay, cut it to length and then glue and hammer it in place. Using a sharp chisel, I then shape the plug to the desired profile. In this case, I made Gothic-style peaks to my plugs.