I was recently approached by Dash Weidhofer, a former Ranger & Public Access Coordinator for the Wildland Conservancy's 5,630 acre Jenner Headlands Preserve. Dash had the idea that we (he and I) could make a number of picture frames from old-growth redwood boards reclaimed from old buildings on the Headlands. These frames will be used in a photography display being set up at the Headlands headquarters.
The kind of frames that we made are shown below.
One would think that making a picture frame would be a simple project, but doing a good job is not as easy as it seems. This page discusses methods that are appropriate for most well-equipped home workshops. Of course, there is professional production equipment available that would make things easier still and less labor-intensive, but such equipment is way beyond what most home shops could afford. I recommend that you read this entire page before beginning any work. That way, you will understand the whole process as you go along.
Using reclaimed wood makes things even harder. The boards we used are window trim from an old barn and they were severely weathered; although being redwood, there was good wood under the weathering.
We first had to remove any old nails in the boards, and then we ran them through my thickness planer machine. We planed both sides of the boards until all weathering was removed. On the wood for the first set of frames, we ended up with 7/8" thickness, which was ideal for the frames we had in mind. The boards were approximately 6" in width; we decided the width of the frame pieces should be 2-1/2", so we could get two pieces of framing from each board, with enough extra width remaining to assure that we could have good edges without any weathering showing. Note: this discussion gives recommendations for using redwood, which is a soft wood; making frames with other wood types may require different considerations.
The planed, reclaimed wood showed a large variation in the color of different boards. [picture?] We had to be sure that all the sides for a given frame came from the same board for good color match in the finished frame. Since it is easier to handle shorter boards through the next steps of the process, namely, ripping to width and jointing the cut edges, we first cut the planed boards to rough lengths for each frame (the intended frames were not all the same size), selecting the cuts to avoid any holes or splits in the original boards. So two pieces of the 6" wide wood contain all the wood for one frame. We kept these pieces together through all the rest of the process.
The next step was to rip the board pieces to the width of the frame sides, 2-1/2 inches. To begin this process, we jointed one edge of each piece to remove all weathering of the edges. This edge was then used on the table saw for the 2-1/2-in cuts to the width of the frame sides. [might use pictures of the jointing and ripping process here]. After this, we have 4 pieces of matched wood color for each frame.
Now we had to cut the rabbet (notch) on the back of each frame side, that holds the content in the frame. The rabbet would be half the thickness of the piece (7/16-in), and would be 1/2-in deep. Before doing any cutting, we examined each piece and decided which side would be the back of that piece and which edge would be best for the rabbet. Using a Sharpie pen, we marked the back of each piece with "B" and stacked the pieces with B down and the side for the rabbet on the right side of the stack. Often rabbets are cut with a shaper or router, but this could risk splitting the redwood. To avoid this risk, we used the table saw to make the rabbet, which takes two cuts perpendicular to each other.
It doesn't matter which of the two rabbet cuts you do first. Let's choose the first cut to be the one you do with the piece flat on the saw table. The saw height is set for the blade to project above the table by half the thickness of the piece, and the fence is positioned so it is the depth of the rabbet away from the left side of the blade. If the pieces are reasonable length, you can probably do this cut pushing the piece by hand. However, you should use a push stick so your hands don't have to go close to the blade, and the piece should be held down to the table and against the fence. Each piece should have the "B" side down on the table, and the side chosen for the rabbet against the fence. The second cut is done with the piece on edge with the "B" side against the fence and the side with the first rabbet cut against the table. However the saw height and fence have to be readjusted so the saw just cuts the rabbet out ending with a nice clean bottom corner to the rabbet. In making this cut, the sliver of wood being removed will be trapped between the blade and the fence and usually will fly out when the cut completes. Be sure you are not standing in line with the blade so you won't be hit by that piece.
Now comes the most critical operation: cutting the miters. There are three important factors here: the saw blade must be exactly perpendicular to the table, the miter angle must be exactly 45°, and the length of opposite sides of the frame should be exactly the same. The latter requirement is easily met by cutting the two opposing sides at the same side (stacked up on the saw table). The miter angle requires some experimenting. The picture below shows the miter setup I use: The miter gauge that came with my 75-year-old Delta Unisaw. This is set to 45° on the gauge scale and locked against the stop. Miters are cut on two trial pieces (one end only). You can do this with the pieces stacked as described above. Then the cut ends are placed together inside an accurate square (You know how to test the accuracy of a square?) If the miter faces come exactly together the first time, you are extremely lucky. If not, adjust the miter gauge stop a small amount in the direction that will close the gap in the miter and cut again on the same pieces. Repeat this until you get it as close as you like. Throughout this process, you need to be sure every time that the pieces are clamped tightly against the miter gauge fence.
Once this is done, you can cut one end of the frame pieces. Make sure the rabbet side is away from the miter gauge fence, and cut. For cutting the other end of the pieces, you need to determine the proper length for the pieces. Most frame sizes are specified in terms of lengths measured inside the rabbet, in other words, the size of the content for the frame. You usually add 1/8-in for clearance around the contents. This distance can be measured with a good metal ruler along the inside surface of the rabbet, but then you have to transfer this measurement to the flat surface of the piece so you can set it up with the saw blade. A trick here will help: make the first cut with the rabbet side of the pieces down against the table and away from the miter gauge fence. For the second cut you simply flip the stacked pieces end-to-end and the rabbet will now be on the top away from the fence. This makes it so that you won't have to change the miter gauge setting--never change that!. Using a 45° square, transfer your marked length on the rabbet to the top surface of the stack. You position the stacked pieces for the cut using your metal ruler flat against the side of the saw blade and move the pieces until the saw will cut exactly along your marked line. While doing this, be sure the other ends of the pieces are aligned so the two pieces will come out the same length. It is helpful when doing this to use a small square or square block of wood to align the two pieces. Clamp down, recheck and cut. You now have your first pair of sides for the frame. Repeat all this for the other side. Now you're ready to see just how good your miters are. [some pictures are needed for this paragraph]
Assembling the four pieces of the frame requires a means for clamping the frame. I highly recommend a frame clamp sold by Rockler, Grizzly, Amazon, and others. It is around $35 and clamps all four corners simultaneously. The picture below shows the use of that clamp. [picture] To use the clamp set it up on a flat surface with the four aluminum rails splayed out in an "X" pattern. Position your frame pieces on top of the rails with the miters roughly together and determine where the plastic clamp pieces should be located. Lock them in place in the rails and tighten the clamp with the wing-nut bolt in the center. You may need to rotate the plastic clamp pieces a little to get best fit at the corners. It is best to use the large notches in the plastic pieces, but depending on what type of joining you are going to use (more on this below), you may not get enough access to the corners of the frame when using the wide notches.
There are a number of options for how you join the mitered corners when they are ready for completion. Ones that I have used include glue alone, glue with biscuits, glue with screws, or glue with splines. For this project we chose glue with screws, which is the only option above that will not fall apart if the glue fails. Of course, the screws are counterbored and covered with cross-grain plugs.
Glue with screws requires additional preparation of the pieces to accommodate the screws. I use one screw per corner, and if you know how the frame will be oriented, you can put the screws on the top and bottom corners where they will be least visible. (I personally think the cross-grain plugs look cool, and I would put them on the sides of the frame where everyone can view my handiwork. The extra steps are: counterbore for the screws, pre-bore for the screw itself, and make the cross-grain plugs with the same wood as the frame.
The counterbore for the screws is centered in the edge of the side piece at a location where the screw will engage the adjacent side piece in the center of the wood outside of the rabbet. (Note: make sure the location of the counterbore will be accessible when the frame is in the clamp.) Use a 3/8-in spur bit and set the drill stop to go 1/4 to 5/16-in deep. After the counterbores are drilled, switch to a bit that matches the shank of the screws you will use and drill all the way through the side piece in the center of the counterbore hole. [pictures]
Making the cross-grain plugs begins with a plug cutter bit for the drill press. Using a piece of the same wood as the frames, drill with the plug cutter about 1/2-in deep, not going all the way through the wood. [picture] You can drill for plugs close together, although the holes should not touch. The plug cutter requires that the workpiece be tightly held; if not, the cutter could jam, the plug could be broken, or worse. I find that a fixture as shown in the picture and tightly held against the fence with a gloved left hand, works fine. This is much easier than clamping, which would require stopping and clamping in a new position for each plug. After the plugs are drilled, you should use a marking pen to mark the direction of grain on each plug. This makes it much easier to get the correct orientation when gluing in the plugs. Once you have drilled for the number of plugs you want, you release them by cutting across the board underneath the plugs. Plugs should be about 3/8-in long. Be sure to make some arrangement to catch the plugs when they come out or they will go all over the place. A rag placed next to the bandsaw operation does the job.
You are now ready for final assembly, gluing and screwing the corners. You should have ready a drill with a bit of the screw thread root diameter to pre-drill the screw holes. This is because redwood splits easily. If not done already, switch the frame clamp to use the small notches in the plastic clamp corners and re-tighten the clamp. Now loosen the frame clamp so the sides can be easily removed. For glue, I recommend Gorilla Glue, original version. To begin gluing, moisten one end of each piece with water. Then apply glue to each moistened end. A thin layer is enough, put it on from the container and spread it with a flat stick. Be sure to get glue on the narrow wood above the rabbet. You want as little glue to squeeze out in the clamping process. This will take more sanding to remove. If you have used Gorilla Glue before, you will know the right amount of glue to apply. After gluing, replace the pieces in the clamp with the rabbet side down, and tighten lightly until the pieces just come together. Then press down on the corners to make sure the pieces are aligned vertically; tighten the clamp fully. Once that is done, you are ready for the screws, which should be put in before the glue cures. Pre-drill the screw holes, insert the screws, tighten them snugly, but not too tight. Making them too tight could cause splitting or crushing of the redwood.
When the glue has cured (4 hours or more), you can remove the frame from the clamp. Using a sharp chisel, carefully scrape off any glue on the frame surfaces. You don't need to get it all off at this time: sanding will do that later. Now is time to insert the plugs in the screw holes. Pour out a little glue on a disposable surface. Dip the un-marked end of a plug in the glue and carefully align it over a screw hole. It is best to clamp the frame in a bench vise so the edge with the screw holes is facing up. Once the plug is aligned and rotated so the grain marking matches the wood, tap the plug into the hole. [picture] You should not tap it all the way in, there should be some of the plug sticking out of the hole. Repeat for the other plugs. When the glue is cured, the excess plug can be removed carefully with a chisel and hammer. [picture] Even then, do not take it all off; leave a little sticking up (this is because the plug will sometimes split deeper than your chisel); a small excess of plug sticking out can be easily taken down by sanding with a block sander using 100-grit paper. While doing this, sand the entire side of the frame to remove any tool marks from the saw or jointer, as well as any glue residue. Sand all 4 sides this way.
The face of the frame can be sanded with an orbital sander with 100-grit paper to remove any slight misalignment at the corners, glue marks, or other blemishes. [picture] From here, the final finishing is up to you. We routed the edges outside and inside with a 1/8-in roundover bit. The router leaves a little material on the inside corners which can be cleaned up using a sanding block to continue the router's radius all the way into the corners. You can finish up the entire frame by hand sanding with 220-grit paper.
We finished our frames with Varathane Water-based Diamond Finish Interior Gloss--four coats with light sanding between coats. If a satin finish is desired, a final coat of Varathane satin or semi-gloss varnish will do the trick. [picture]
Of course there are many other variations of frame design or finishing that can be applied. However, the principles of mitered corner construction presented here would still apply.