Jigs for Creating Picture Frames with Compound Miters

under construction 7-10-07 - needs repair

This post shows designs for

1. Cutting Compound Miters, using 
a jig for cutting compound miters for constructing picture frames; 
2. A clamping system, that is, a jig for gluing-up picture frames with compound-angled corners
I prefer to use a system for cutting the sides of picture frames that I devised myself for my radial arm saw. This system also works as well on a table saw.

My first photo is a picture of my Dad that I created out an old 4” X 5” box camera photo that I found in family memorabilia. The over-all dimensions of this frame are 19” w x 21” h, with the sides of the frame 3” w. The photo itself is standard 8” x 11” (I printed the photo with with my scanner and HP printer) but had the photo professionally matted. I also did a similar picture for my mother.

As well as barn wood, I have examples of frames constructed from molding that I have created with my shaper. 

The frame in the photo below does not do justice to the frame’s 30˚ cant, a feature that gives considerable depth to the frame, depth that is missing when you simply glue up mitered frames at flat, 90˚ angles.

The photo of my Dad looks professional, largely, I think, because it is professionally matted. (For a joint funeral for my parents, I framed pictures of both my parents.) The racoon on the lower left is a Christmas gift for a friend of my wife. It's better at giving a sense of the depth of the frame that is obtained with the 30 degree slant on the frame's sides.

photo of dadframed racoon

The depth the cant, 30 degrees, makes the frame, for me at least, quite striking. Photographed straight on, as for my Dad's (above) photo, this cant is hard to perceive.

Let me say that with more adept photography, the depth that the cant on the frame’s sides gives the picture an attractive appearance, certainly different than the rather heavy handed simple mitered corner look.

The material in the frame itself is old growth Douglas fir, taken from a 100-year old barn. Again, we live in the Puget Sound area of Washington State. 

1. Cutting Compound Miters

The photo below, the four sides in prep for gluing, on the left, shows the angle or "cant" in the frame.

The photo on the right, directly below, shot from the side, gives you an idea of the angle/cant of the frame.
prep for glue-up


compound joint

Experienced woodworkers will, immediately, understand that my technique allows you to overcome a difficulty inherent in working with "weathered barn wood." The charm of this media, the aged, "weathered" look, must be preserved; otherwise the aged appearance that you wish to achieve in the frame is ruined. Why? Once you cut weathered boards, a fresh cut is exposed. [will get a picture to illustrate soon]

In creating a frame, I first cut the "square" rabbets, i.e., the grooves, for inserting the glass and  matted picture. After some experimenting, I found that by setting the  "L"-angled aluminum into a rabbet (groove) on the underside of the jig, at the outer edge of the 30° angle, and having the "rabbets" in the workpieces pre-cut (explained below), you cut each of the four sides accurately. This rule is especially true when constructing frames out of weathered boards, where the edges of barn borads are rendered uneven by decades of rain, sleet, and wind.
Making the square rabbet/groove.

Again, my saw blade is set at 30 degrees. I place the fence to the right of the blade, just far enough that I able to place the kerf line exactly on the corner of the weathered board (check the blade's location in both left and right photos below). For the next cut (no picture yet), I move the fence over to the right, lay the board on its side, so that the cut cleanly removes the material and leaves a square rabbet, as illustrated in photo directly above, on right.

square rabbetcutting square rabbet

square rabbet 2

Cutting the Sides of the Frame
In the group four photos clustered below, the photo on the left top is an "end" view of the jig, showing: (1) the 30 ° angle, (2) T-track (for precisely cutting lengths of frame sides. and (3) aluminum "angle iron", for a precise cutting of the frame's sides. On the top right is the same jig, this time placed on the right of my Delta radial arm saw. On the bottom, left and right,  are "before-and-after" photos that show how the sides of the frames are precisely cut. (The secret is that, using the combination of the T-track and the "L"-angled aluminum.)

jig for cutting frame on radial arm saw

frame cut to length 2
frames cut to length

cutting frames on tablesaw

My jigs let woodworkers who lack the compound miter saw to easily make three dimensional frames with compound miters on the tablesaw. 

exposed saw cuts on weather board
In the photo left is illustrated a downside of using weathereed barnwood. Every cut exposes wood that is not weathered. To avoid exposing these cuts, I cut the picture frames sides so that these exposed areas are always on the inside of the frame, "inside" in the sense that when the four sides are glued up, the cuts are located where the picture is placed in the frame.

Setting the saw blade at 30 degrees, I make two cuts, that form a "square rabbet". (See photo below, on right.) This square rabbet is cut so that the exposed, "fresh" wood is all eliminated, with the weathered frame sitting next to the matte, between the frame and the picture. For an example, look closely at the framed photo of my father, at the top, and focus on where the frame meets the matte.

2. Clamping System


The clamping system I use is from Lee Valley, but the clamps look very similar to Woodworker Supply catalog, no 139-745. 

The photo below shows several features about this system: Use of biscuits for better glue up on compound angles at corners. Specially created clamps for holding angled corners securely, with surfaces tightly held together by metal “clips”, while glue sets.

glue-up 1

glue-up 2

The photo above below shows the final clamping set up. I pondered this problem (i.e., how to glue corners with compound angles) for many years, and, when I saw this clamping system in the Lee Valley catalog, finally settled on this solution. If there’s a “secret’, it is the clamps that I have created, which during glue up, with the aid of the metal “clips”, hold the surfaces of the compound angles tightly together, very important if the glue up is expected to last.

[needs editing] For the glue-up, the corner frames that I made have metal “cleats” that, corner by corner, apply pressure uniformly. (I bought the clamping system at lee valley store in coquitlam.) I was surprised myself at how efficient this clamp is. The clamping set-up itself I bought at lee valley. Before I thought of this solution, for glue-up, I used a brad nailer to hold one corner at a time, not a satisfactory way to go.

If there is a downside, it is that the angle (in this photo, the bent metal “clip”) that helps secure good surface bonding is “fixed”. In this case the angle is 30˚. How make this clamp with an adjustable angle has, so far, eluded me. More important, is an adjustment mechanism needed? Most frames will be satisfactorily glued up with 30˚ cants. If other angles are desirable, plastic clamps with a variety of angles can be offered.


corner clamp
need better photo than above

The photo below shows the picture frame's corner at a different angle.

"Sizing" the frame to the matte. sizing the frame[need details here about difficulty of measuring appropiate size of frame's rabbet.]