Canadian Woodworking

The power of wedges

Author: Steve Der-Garabedian
Photos: Steve Der-Garabedian
Published: June july 2021
The power of wedges
The power of wedges

The simple yet powerful wedge has been around for more than two million years and is still useful in the world of woodworking.

The sharp end dives right in and with a few blows on the blunt end you can either split a log or seat something nice and tight. Using a wedge for wooden hand planes, clamping wood panels, holding workpieces and securing sandpaper is just the beginning. Let’s make a bunch.

They’re everywhere you look. I’m talking about the sim­plest tool of all — the powerful wedge. Just take a look around. An axe works very well due to its wedged-shaped head. I use wedges when I make hammers to make sure the head doesn’t fly off. If you’ve ever made a Krenovian-style wooden plane, then you’ve made a wedge to hold the blade tight to the rear ramp. In fact, take a look at the bevel of the blade. Remind you of a particular shape? They’re also used to lock in joinery, such as a wedged mortise and tenon or a tusk tenon. A wedge is also used to hold the lid shut on a Japanese-style toolbox.

It’s not just in the shop, either. My parents used to place those hard rubber wedges on the floor to hold doors open. Wheel chocks stop trailers, cars and even airplanes from budging an inch and are in the shape of a wedge. Should I even mention the power of potato wedges or a wedge of delicious cheesecake? I apologize, it’s almost lunch time.

Start with a Jig
Although there are many approaches to making wedges, Der-Garabedian’s first step is to draw the wedge shape in full size. Keep in mind the grain of the wood must run the length of the wedge to be strong.

Pretty Close
Although you don’t have to be perfect, cutting your jig straight will go a long way to creating good wedges.

cut wedges

Trim the Jig to Size
Der-Garabedian rotates his jig, then references off his band saw fence while cutting it to size. He then leaves the fence locked in the same position. This means the jig will cut a piece of solid wood to the correct wedge shape and size when the jig is rotated back to its standard position.

Zero Clearance
Although not always needed, a thin sheet of hardboard taped to your band saw table will stop any small wedges from getting caught in the blade and throat.

Flip Flop
After making your first wedge, flip the stock over to make the next wedge. This “back-and-forth” process will ensure the grain always runs the length of the wedge, making it as strong as possible.

Cut the Recess
There are many ways to remove the material in the end of your sanding block. Der-Garabedian uses a crosscut sled and a pair of stop blocks to get the job done.

Remove Wedges
Although they won’t be used in this sanding block project, wedges are removed from the outer faces of the block, as well as on the smaller, inner faces.

Trace and Cut
Der-Garabedian traces the shape of the rear cavity onto the end grain of a length of lumber, then creates the wedge that will fit into this cavity to hold the sandpaper in place with an assortment of machines and tools.

Wedge It in There
The wedge that holds the sandpaper in place will also keep it taut and ready for action. Sized properly, it will hold 1/3 of a sheet of sandpaper.

Blocks for Stability
In order to keep the dowel from rotating or shifting while cutting it down the center on a band saw, Der-Garabedian creates a pair of solid wood cradles for either end of the dowel to fit into. Once the cradles are split in half, they can be used to support the dowel while you bore a hole through it to accept the bolt.

Clearance Hole
Using the split cradles for support, drill a slightly oversized hole through the dowel, perpendicular to the band saw cut.

Small, Yet Simple
Your new clamping aid will go a long way to holding tiny parts in place when you need to sand or shape them.

Simple Layout
Two simple layout lines are all that’s needed for this work-holding device.

A Strong Bite
The slightly rough band sawn edges of the wedge and main section of the jig provide a lot of friction and hold a workpiece stationary when in use.

Tame Thin Glue-ups
Once the wedge is tapped into place it provides more than enough pressure to hold thin pieces of wood together while the glue dries. It also keeps the workpieces flat while being glued.

Any Length
Bar clamps of virtually any length can be made from wood. A few holes over the length of the wood will allow you to glue up many different widths of panels. Notice Der-Garabedian has chamfered the edges of the holes for easy dowel insertion.

No Movement
Hot gluing thin wedges in place to support a cupped or twisted piece of lumber will keep the material from moving while you flatten the upper face of the wood with a thickness planer. It doesn’t need to be pretty. A thick, dense piece of wood needs fewer support wedges, while a thinner piece needs more. When in doubt, more is better.

Cupped Upward
Notice Der-Garabedian placed the concave face of the cupped board upward when securing the lumber to his sled base. He used wedges on the outside edges wherever needed to support the material.

Making wedges

Wedges can be shop-made several ways. You can chop a few, but make sure you have a sharp edge, unlike the rusty one on my axe. More practical is a small hand saw or, better yet, a band saw.

For the sanding block and small parts vise below, I used a longer-than-needed piece of wood and slowly cut it free-hand on the band saw. For all others I like to use the jig as shown below, and in a video you can find on the CW&HI website.

A bit of band saw work

Use a piece of MDF or plywood roughly 12″ long × 6″ wide and around 1/2″ or 3/4″ thick with the long edges parallel. On one long edge of your jig, draw two lines using a square that are separated by the length of the wedge that you want. On the lower line, place a pencil tick as to how thick you want the wedge to be on its blunt end. Join this tick line to the upper line at the edge. You now have a picture of your wedge.

Head to the band saw with your new jig and bring along a piece of 1/8″ thick hardboard and some blue masking tape. The hard­board should be approximately the depth of your band saw table and about 3/4 as wide. Cut out the wedge. While the cuts don’t have to be perfect, take your time and get as close to the shape as you’ve drawn. In order to get good results, we need this side to brush against the blade. You can adjust the fence back and forth, but what I find easiest is to turn the jig around and set the fence to cut about 1/4″ off the blank end. Complete the cut and when the jig is turned back around it will line up perfectly.

It’s unlikely large wedges will slip into the throat plate opening, but small pieces will annoyingly drop in and jam, forcing you to stop the band saw and clear them. Make your own zero-clearance insert with a piece of thin hardboard. Since the fence is now locked in position, cut about halfway into the hardboard. You can use clamps, but I find some strategically placed blue tape is more than enough to stop it from moving.

Take stock

It’s important to cut your wedges with the long grain running down their length. Cutting in the opposite direction creates weak wedges that will easily break. Mill up your stock to the thickness required and cross cut the stock to the length needed. Keeping the jig against the fence and pushing the stock against the jig, cut your first wedge. In order to keep producing long-grain wedges, flip the stock over and repeat. Keep doing this until you’ve got enough wedges for your job or the stock gets too small and your fingers get too close to the blade. Wedges of any practical size can be made in this manner.

Putting wedges into action

Here are a few simple shop projects that showcase the simplicity and power of a wedge. Sanding blocks are very useful in the shop and shaping them like a wedge will ensure they get into almost all spots. I like to make my own handles and knobs for box lids and drawers but holding small pieces can be a challenge. How about a small vise made with nothing more than a dowel, a wedge, washers, a nut and bolt? You know the saying, “You can never have enough clamps.” How about a “wedged” solution? Finally, a really simple, neat trick to be able to use your thickness planer as a wide jointer.

Sanding block

Sanding blocks are great in the shop as they are easy on the hands and when sized right will use just the right amount of sand­paper. Start off with a block of hardwood that’s 4-1/2″ long × 3″ wide × 2″ thick. Cut a groove centered on its width 1″ deep and 3/4″ wide. Find the center of this groove and drill a hole approxi­mately 1″ deep to be able to drive in a 1/4″-20 threaded insert. In my case, the insert called for a 3/8″ hole. However, because I used hard maple, I ended up sizing the hole a bit bigger at 13/32″. Drive in the insert about 1/8″ below the surface. On one side of the block, draw the desired shape and cut it out on the band saw. Using hand planes, files or sandpaper, smooth all surfaces and round over all sharp edges. Trace the shape of the opening for the wedge onto some appropriately sized material, and once again cut and smooth this using whatever tools you have and are comfortable with. The fit doesn’t have to be absolutely perfect but take your time and come somewhat close. Drill a 9/32″ hole in the wedge to be able to use a 1/4″- 20 thumb screw or similar to tighten the wedge into its home. I find when in use the wedge can just be pushed into place. Between the action of the wedge and the sandpaper everything is held nice and taut. Give the block a bit of cushioning by adding some cork. This size of block lets you fully use three strips from a sheet of 9″ × 11″ sandpaper.

Small parts vise

This vise is similar to a jeweller’s ring clamp used for holding rings and other small pieces of jewellery. I tried a few different ver­sions using square stock and a hose clamp as the pivot point, but in the end the version utilizing a dowel worked great. I made two models. One with a V-groove down the middle to better hold round stock and the second I lined with cork to gently yet firmly hold small, thin pieces.

Start off with a 1″ diameter dowel that’s 6″ long. We’ll need to cut it in half, which can be tricky. You can make a V-grooved base or, like me, take 1-1/4″ square stock and drill a 1″ hole in the middle. Fit each end of the dowel with a square ring and cut it in half on the band saw. Using your freshly made sanding block, give the rough surfaces a gentle cleaning, then tape the pieces together. Cradle the dowel on the half squares and drill a 9/32″ hole in the center of the dowel. Your eye is a pretty good judge of where cen­ter is along the dowel’s diameter. You can also line up the split in the dowel with the top of the cradle. Using a longer than required piece of wood, free-hand cut a wedge using the band saw. Smooth it out using a small block plane, sandpaper or a file before trimming it to length.

Assemble your vise with a round head bolt and wing nut. I find pivoting is aided if there is a washer or two between the halves. In order to get the proper spread for clamping, I place the stock in the pivot point and tighten the wing nut until the two pieces lightly pinch it. Now place the piece at the top and drive the wedge in from the opposite side. You’ll find that your pieces are held surpris­ingly tight. As mentioned above, I placed a groove in one version and cork on the other. If you like, you can sand the clamping end of your vise into a cone shape to give you more access to what you’re working on. Play around with the shape and size of the wedge to best clamp your work.

From the mouth of birds

A bird’s mouth is a traditional way of holding work on edge. While my front vise can do basically the same thing, a bird’s mouth lets me hold longer pieces on the bench and most times at a more comfortable height.

Starting off with a piece of hardwood approximately 1″ × 5″ × 15”, draw a line parallel to one side, 3/4″ in and 8-1/2″ long. Next, draw an angled line 1-1/4″ in from the other side and down to the end of the first line. This gives you an approximate 20° angle. Cut this out on the band saw. Smooth the resulting wedge and cut off the point. This doesn’t have to be perfect; in fact, a bit of rough­ness along with the wedge shape will help lock things in place nicely.

To secure the jig to the workbench, drill a 3/4″ hole for a bench dog and use a hold down. Slide your piece to be worked on into the jig and press the wedge into action. A few light taps will hold the piece and give you full access to your work.

A pair of clamping solutions

Since you can’t have enough clamps, we will make a few to add to your collection. The first version is for clamping thin pieces. The second is a panel clamp of sorts that can be made to almost any length.
Clamping thin stock, such as that used in small box bottoms, is always a bit tricky. Wedges to the rescue. Start with a piece of MDF larger than the pieces being glued. As we don’t want our pieces per­manently attached to the MDF base, lay down some packing tape, making sure to overlap each row slightly. Next, attach a fence par­allel to one edge with screws. Place the pieces to be glued down on the MDF along with a low angle wedge (roughly 7°) and another MDF fence. Screw this second fence down to the base as well. All that remains is to apply glue to the edges, lay the pieces down, and tap the wedge, securing the pieces tight and flat.

Making extra clamps when you need them is nothing more than having some wood (preferably hardwood), a pair of dowels and wedges. While you could get away with regular clamps on this edge glue-up, it was more to demonstrate how easy of a setup it can be to make a clamp or two if your longest bar clamp wasn’t long enough for a task. I normally use 3/4″ flat stock roughly 3″ wide, white ash in this case, and place a 3/4″ diam­eter hole 1-1/2″ from the end for a dowel. On the other end you can place multiple holes to suit the width of the glue-up. Use a pair of wedges on each end and, as with regular clamps, use cauls to help distribute clamping pressure and protect edges. Line up the wedges so their sloped sides are facing each other and, very impor­tantly, don’t forget packing tape on the inside faces.

Wider jointing

To mill wide rough lumber, you would typically first rip it down to the capacity of your jointer, then joint and plane it to thick­ness. It’s relatively easy to re-join stock after milling, but there are times you won’t want to break up the grain pattern to what is lost by cutting and edge jointing. Break out the hot glue gun, MDF and your wedge-making jig. Place your wobbly lumber on top of a slightly wider and longer piece of MDF and use wedges to take up any gaps between the two. Hot glue these wedges and send your assembly through the thickness planer. Once the top is flat, drive in another wedge to separate the two, flip your stock over and thick­ness as usual.

Angles and cheesecake

Here are a couple of points about wedge angles. While I haven’t given specific angles to cut the wedges, you will find that for wooden planes, mortise and tenons, and tusk tenons, lower angles somewhere in the range of 5° to 7° work best. A 20° angle works well for the bird’s mouth and could even work as a single wedge in the panel clamp. Play around with the angles, but you’ll find some­times steeper angles pop out during use while shallow angles don’t provide enough flexibility.

Normally, at the end of an article I sug­gest giving the project a try. But you probably already have. Now, where did I put that wedge of cheesecake?

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