Introduction: Dovetailed Wooden Glasses
This instructable describes every step involved in duplicating your existing prescription frames or sunglasses into a wooden dovetailed frame. If you are making prescription frames care must be taken to ensure that the geometry remains the same.
This project started because I was sick of the hinges failing on my glasses, so I decided to make a pair that didn't include hinges. Since I'm a cabinetmaker, dovetails seemed to be the most obvious choice. The photos in this tutorial are from several different pairs I've made. I've been wearing mine for many months now and they're the lightest, most comfortable glasses I've ever had, and because of the laminated construction, they've proven to be very durable. Let's get started!
Step 1: Making the Bending Form
The first step in the making of wooden frames is to create a form in which you can produce the bent lamination needed for the front of the frames. If you look at your glasses, you'll see that they are curved lengthwise. This curve may or may not be even, so on a block of wood larger then the frames, I sketch the curve lightly while holding the frames in place. Make sure to draw a centre line to keep things straight, then use a french curve or a large compass to make a clean cut line. Cut out the curve in one pass on a bandsaw, then sand it lightly to remove any burrs or humps. A slightly rough surface here doesn't matter because this form is only for creating the shape. Cover both surfaces of the curve with packing tape so that glue will not stick to it, and you're ready to laminate.
Step 2: Selecting the Materials
The frames are made like a piece of plywood. Five layers of veneer 1/32" thick are stacked up and laminated together. The grain orientation alternates directions, going from straight across on the front, then top to bottom on the next, then continues alternating all the way through.
Woods should be as clear and straight grained as possible for strength and workability. I'm using scrap wood to make my glasses, so I've used several smaller pieces to make up the interior layers. The woods in this photo are Ebony (black coloured) and Yew.
Make up your stack of veneers taller and wider then your frames, so that there is some margin for error if the pieces slip around.
Step 3: Selecting a Glue
There are many different glues on the market, and just as many opinions about the pros and cons of each one. I want my glasses to be very strong, waterproof, and dimensionally stable, so I'm using epoxy.
Make sure to use a slow hardener so that you have plenty of time to work with it, and I like to add a little colloidal silica to the epoxy to give some body. This prevents it from running out of the lamination. I like West System 105 resin and 206 hardener, but they also make G-Flex in a smaller presentation.
Whenever you use epoxy make sure to be safe and protect your skin, eyes and lungs. If you get epoxy on your skin, DO NOT use a solvent to get it off, this actually pushes it through your skin faster, wipe it off with a paper towel, then use a citrus hand cleaner and warm water several times.
Step 4: Glueing Up the Lamination
Coat the mating surfaces of your lamination package with adhesive and stack them together in a bunch. To keep them from sliding around I shoot a micro pin through the corners that will later be cut off, but you can also wrap the package in stretchy plastic wrap, or some tape.
Position it in the form and clamp it up with light to medium pressure. If you clamp it too hard you can cause a "starved" lamination where all the glue is squeezed out from where it needs to be. Allow it to dry for at least 24 hours before removing the clamps.
Step 5: Removing the Lamination From the Form
After the glue is dried, I use a belt sander to remove the squeeze out from the edges, then I mark the centre line from my form onto the lamination. Extend this line squarely down both the inside and outside surfaces.
Step 6: Laying Out the Frames
Using your old glasses as a template, carefully draw the perimeter of both the inside and outside of the frames. I use small spring clamps to hold them in place so they don't shift around.
At this point you'll probably have to make them slightly wider to accommodate the dovetail joint. The arms are 3/16" thick, so make sure there's enough wood for the joint plus enough to hold the frames together.
Step 7: Cut the Lens Opening
I use a scroll saw to cut out the lens opening from the inside of the lamination. I cut as close to the line as possible now, then sand or file the openings until they look even to your eye and even to the touch. At this point the openings should still be too small for the lenses. Don't forget to wear a dust mask.
Step 8: Fit the Lenses
I put a small drum sander in the drill press, and raise the table until it's 1/16" away from the drum. Carefully sand the perimeter of the lens opening until the lens can be pressed into the cavity. There should now be a small lip around the outside that traps the lens.
Step 9: Preparing for the Dovetail
It's much easier to cut dovetails at 90 degrees, so cut the ends of your lamination square, then mark the thickness of the arms onto the frame with a marking gauge or sharp pencil. Lay the blank on a piece of sandpaper, and sand a square shoulder up to your layout line.
Now you can cut out the outer perimeter of the frames. I also cut this out on the scroll saw, and shape it smooth with files and sandpaper.
Step 10: Material for the Arms
You can make the arms from either solid wood, or a bent lamination. The picture shows the view from above, of how I cut a set of arms from a single 3/4" board. Select material that's strong and free of knots with even grain that will cut nicely for ease of making the dovetails. The arms can be as showy or understated as you like, but they're a fun place to highlight a really special piece of wood.
Step 11: Getting It Right
This is where the really important stuff starts. When you sit your glasses open and down on a table, you'll see that the face of the frames is not necessarily perpendicular to the arms. Many frames actually angle forward (or maybe backward) depending on your own head. I figure out the angle of my frames and trap them between blocks so that I can determine the angle that the arms should meet the frames. I draw this angle onto the wood and then cut and trim this angle down to the line. This can be done with any tool you have available. Just make sure that the end is square to the side for laying out the dovetail.
Step 12: Cutting the Tails
Lay out the tails length with a marking gauge by scoring a line all around the perimeter of the angled end of the arm blank. Choose the layout and angle of tails that suits your own taste and layout the joint on the end of the arms. Square lines across the end grain help to keep you cutting straight across.
Use a small crafting saw to cut down to the scribed line on each side of the tails.
I like to angle my board when I cut so the saw travels vertically, this makes it easier to get straight cuts that will require less cleanup later.
Step 13: Cleaning Up the Tails
I cut a little shoulder to guide the saw for removing waste from either side, and I use a coping saw to remove the waste from the middle.
At this point you should still be able to see your layout marks, so using a sharp chisel or knife, work everything down to its layout line and clean it up so you can transfer the shape to the frames.
Step 14: Double Check
Make sure at this point that you're happy with all the angles, and that your arms match the geometry of the original frames. If adjustments need to be made, now's the time to do it.
Step 15: Transferring the Lay Out
Clamp the arm in a Jorgensen style clamp or something similar with the shoulder flush with the surface and only the tails emerging. Hold the frames up to the arm, and using a sharp knife, carefully trace the angle of the tails onto the frames. Careful not to cut yourself here, because you'll be working close to your fingers. Mark the depth of cut (thickness of the arms) with a marking gauge onto the frames.
Step 16: Cutting the Pins
I use a small craft saw again to cut down to the layout line while the frames are held steady in a clamp. I cut out the waste with a coping saw being careful not to go past the layout line. I deepen the layout line with a sharp knife, then pare away the rest of the waste with a small chisel. Clean up the pins to make them straight and square to the layout lines.
Step 17: Fitting the Joint
At this point the joint should be too snug to go together, so take note of where wood needs to be removed and slowly assemble and disassemble the joint until you get the fit just right. I like to draw a little pencil lead onto the sides of the tails, then assemble the joint as far as I can. The tight spots will show on the pins with a pencil smudge, and you can pare them down accordingly.
Once the joint fits it can be finished off in several styles. The ends can be trimmed to follow the curvature of the frames, they can be inset, or they can be rounded over like arts and crafts furniture.
Step 18: Finishing Off
At this point all of the fun shaping and sanding can be done that will give your glasses their own unique character. Make sure to cut out the shape of the arms the same as the original so that your glasses sit straight on your face. Test fit these cuts plenty of times until you're sure you like the fit on your head.
Finish the glasses however you like, I recommend something non toxic because they'll come in direct contact with your skin. Test finishes on scrap wood until you find something you like. I often use a combination of mineral oil and bees wax. I've also used polyurethane on the arms.
Step 19: Enjoy Your Glasses!
If you feel any discomfort from your glasses, you may have gotten the geometry wrong, your local optician may be able to help set things up a little better or make you new lenses. If you're happy with everything, a small dot of CA glue (superglue, krazyglue) top and bottom hold the lenses in place. A few more dots of glue hold the joint together, but you can also not glue the arms and make a few different sets to mix and match. Add a tiny rare earth magnet instead so they can be taken apart and stored safely. Your imagination is the only limitation.
Now you're styling with the coolest frames on the block! Thank you for taking the time to read through this tutorial, and let me know if there's any part that's not clear, I'm happy to clarify any doubts.