Making the Stringing

Stringing is most easily made by cutting it from a sheet of veneer using a scalpel, hobby knife, veneer saw, or a cutting gauge. But here’s the rub: you’re looking for strings about 1/16″ or more wide, which means that with many of today’s thinner veneers you will have to glue two or three sheets of veneer together to get adequate thickness. Another alternative is to cut thin strips of solid wood using the table saw equipped with a thin kerf blade, clean them up with a bench plane, and then use a knife, cutting gauge or saw to slice strings off of these strips.

No matter which tool you choose, use a light touch when cutting. If you apply too much pressure, the blade will follow the grain and your cut will wander. Instead, use repeated light strokes of the knife or saw to sever the wood’s fibres.

It takes quite a few passes of a knife to cut through the veneer or wood strip. This quickly dulls the tool to less than “razor sharp”. In response, I have turned to using Olfa^®-type utility knives, which use snap-off blades. They’re quicker to change and far cheaper than using hobby knife (e.g., X-Acto^®) blades, which I now reserve for detail work. Although a veneer saw doesn’t dull anywhere near as quickly, multiple light cuts still yield the best result. Joint the wood after cutting off each strip. It’s not safe to joint these tiny strips on a power jointer, however. Instead, place a bench plane upside down in a vise and draw the wood strips over the blade to clean up the edge.

Veneer Saw Tuneup

The first time you use a veneer saw can be frustrating. This is because, like so many tools, a veneer saw requires some preparation before use (and nobody tells you this beforehand). The classic veneer saw has a rectangular blade with convex cutting edges and an offset handle. To prepare it, remove the screws holding the blade to the handle. The teeth will probably be ground square across, whereas what you need is a sharp bevel.

You can use a file or a stone to shape the bevels; a stone is better since it leaves a finer edge. Use a “touch-and-go” type of stroke with the blade on the stone, touching it down and lifting it off as you follow the curve of the blade. Once you have formed a sharp bevel at the cutting edge, turn the blade over and smooth its back on the stone to remove any burr that has been raised. Finally, use the stone to smooth the inside face of the handle where it contacts the blade, making sure there is a smooth mating surface between the two pieces of metal. Reassemble the saw and you’re ready to go.

As an option, there is a new veneer saw on the market made by Chestnut Tools and sold through Lee Valley. This saw has a super-fine blade with 50 teeth per inch milled into its cutting edge and needs next to no preparation. Just unwrap it and get to work.

Cutting the Grooves

Once you have a supply of stringing, cutting the grooves for it is much the same as cutting dados or grooves for regular joinery – just much smaller. You have the choice of using hand or power tools. Hand tools include knives, chisels, scratch stocks and fine saws. For power tools, you might choose a laminate trimmer or small router, but you’d better have nerves of steel and ice water in your veins. That’s a lot of torque to mill a very tiny slot. A Dremel^® rotary tool equipped with a custom router base is a better choice. More on this later.

Hand Tools are Simple and Safe

If I need to make straight or gently curving grooves that parallel an edge, I like to use a scratch stock. This low-tech tool is quiet, relaxing to use, and any mistakes you make tend to be minor – unlike with a router, where if something goes wrong, it goes very wrong. You can buy a scratch stock ready-made, you can convert an old marking gauge, or you can make one “from scratch” (excuse the pun). Ready-made scratch stocks are actually beading tools, designed to cut decorative beads or flutes. You might still find a Stanley No. 66 beader in a usedtool flea market, or you can purchase a reproduction now being made by Lie- Nielsen Toolworks. Veritas also makes a couple of versions of beading tools. Both of these hold steel cutters, which cut beads or flutes. Converting them into a tool to cut channels for string inlay is simply a matter of grinding the right profile into a steel cutter blank. It doesn’t get much easier than that. You can either buy these blanks or you can cut up old scraper, bandsaw or hacksaw blades.

The cutter used for string inlay has one single tooth about 1/16″ wide and 3/32″ long. Its sides are bevelled slightly so that the groove it cuts is a bit narrower at the bottom than at the top. The wooden stringing will have this same slight bevel planed or scraped onto its sides so it fits into the groove like a wedge.

To modify an old marking gauge (or a cheap new one), remove the pin and then cut a slot lengthwise down the gauge’s beam with a bandsaw or fine backsaw. Drill and counterbore a couple of holes crossways through the beam for small bolts and nuts that will secure the cutter. Use the marking gauge’s fence to set your distance from an edge, just as you would do if using the gauge to scribe a line. If you prefer not to modify your marking gauge permanently, remove the beam that holds the pin and replace it with a new beam that is kerfed and drilled to hold a cutter. Also, by making a new, longer beam to hold the cutter, you can cut grooves for stringing as far as several inches from the edge of a workpiece.

To make your own scratch stock, start with a piece of hardwood about six inches long, two or three inches wide and an inch thick. Cut this into an L-shape, then round over the inside face of the shorter leg of the L. This face forms the fence that rides against the edge of the workpiece. Next, saw a vertical kerf down the long leg of the L, stopping just before the face that you rounded over. This kerf will hold the cutter. Drill holes through the long leg to receive bolts and nuts to secure the cutter, just as with the modified marking gauge.

Before you start work, decide whether one cutter will be able to cut the grooves for all the stringing you have to make before it becomes too dull. If not, you’ll need to shape several cutters so if one dulls you can replace it with a new, identical one. To make a batch of cutters, bundle a few blanks together and secure them with tape. Then shape them using a grinder and small files to achieve the profile you need.

To use your scratch stock, secure the cutter in position, hold the fence firmly against the edge of the workpiece, then roll the tool forward slightly and make light, scraping passes with the grain. Gradually roll the tool back more towards the vertical as you continue to scrape, deepening the groove made by the cutter. The action is much like one you would use with a cabinet scraper. Soon you will be able to make light cuts in both directions. Keep the cutter’s tooth free of shavings as you work. As the groove approaches its full depth, the beam will rub against the surface of your work, limiting the depth of cut.

A good sharp cutter in the scratch stock will allow you to make very clean cuts, even when working cross-grain, so long as you keep the cuts light and work patiently. You can also reduce chipping and splintering by first scoring across the grain very carefully with a scalpel, craft knife, wide chisel or plane blade. Don’t rush this fine work. Your attention to detail now will make all the difference to the final result.

When two grooves meet at a corner, cut carefully into the corner for a nice crisp edge using a chisel or plane blade guided by a straightedge or wooden fence. Then place a piece of the stringing against the fence and use it as a shim to reposition the blade. Carefully chop down to cut the other side of the groove. Do the same to cut the corner of the intersecting groove, then use a tiny shopmade chisel to clean out the waste.

Making Custom Chisels

You’ll quickly discover when inlaying stringing that your standard bench chisels are too large for the job. You’ll search long and hard just to find a ⅛” chisel these days, while for stringing you’ll want one only half that size or less.

The solution is to make one. It takes only a few minutes. That’s right, minutes. Start with an old junked chisel, screwdriver, carving tool or other tool with a blade. Use a grinder or belt sander to grind the blade down to the size you need. Have some water handy and quench the blade often so you don’t draw the temper out of the steel. But even if you do blue the steel, little chisels like this do such delicate work that you needn’t worry overly about it dulling too fast. If it concerns you, however, or if you’re using a softer steel to begin with, heat the blade with a propane torch until it glows straw yellow, then quench it in the water.

This will leave the steel hard but brittle. To make it tough, temper it by putting the blade into a 375–400°F oven for an hour. (Okay, so I lied about the “few minutes” part.) Hone the blade as you would any other chisel – flattening the back and honing a smooth, bright bevel.

Cutting Curved Grooves

Curved grooves can be made in a couple of ways. To make an arc you can use a divider with the tip of one leg ground and honed to the same profile as the scratch stock blade. By carefully positioning the tool you can cut arcs with ease. You may find that the pivot point of the other leg of the divider needs to be located outside of the workpiece in order to scribe the arc. In that case, you can clamp or hot-glue a block of wood to your workpiece and locate the leg on that. Once again patience is a virtue here. Many light cuts yield a far neater result than just a few heavy ones, especially when working cross-grain.

More complex curves can be cut using a template and a shop-made two-bladed knife. The knife consists of a couple of X-Acto #11 knife blades fastened together with a spacer the width of the stringing between them, held in a hobby knife handle. The blades are quite flexible but can be made more rigid by fastening them and the spacer together with epoxy. Use the double blade with a pattern of the curve cut from thin hardwood or masonite. Clamp the pattern firmly in place and then score all around it with the knife. Clean out the waste with your shop-made chisel. You’ll probably have to scribe and then chisel out the waste two or three times to get to the right depth. Take your time. Also, you may have to make up more than one double blade so you can replace them as they dull.

And Now for the Power Tool Version

In my opinion, routers – even small laminate trimmers – are overkill for such delicate work. Fortunately, the folks at Stewart-MacDonald – suppliers of tools and materials for stringed instrument makers – provide an alternative. They make a precision router base with an edge guide that fits a Dremel rotary tool. Used with micro spiral router bits, it allows you to route the tiny, precise channels you need for stringing. Stewart-MacDonald also makes an edge guide that fits the router base: use it wherever you have a straight or gently curved section of stringing that parallels an edge.

For tighter curves, it’s better to use a template made of thin plywood or hardboard. Clamp or temporarily glue it to your workpiece and rout around it with the shaft of the router bit rubbing against it like a bearing. Although this may be power-tool work, it doesn’t mean you can speed through it. These tiny router bits are delicate. If you force the cut, you’ll get chatter, resulting in an uneven groove, and eventually a broken bit. So take your time; this needs to be your best work.

Did you enjoy this article?

If you did, read Bill’s follow up article in which he covers how to install and finish the stringing, as well as how to use pre-made bandings to dress up your next project.