Drawing Small Curves

Drawing Small Curves

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If you're drawing challenged, like me, you'll find a set of French curves a real boon when it comes time to lay out graceful curves for a proj­ect. French curves are available individually or in sets in a wide variety of shapes and sizes. Most are made of sturdy acrylic and may be clear or tinted. I prefer the clear curves, as this allows me to easily see the grain so that I can position the curves to maximize interesting grain patterns. French curves are available in most woodworking catalogs and at any art store.

Basic use

I most often use French curves to create patterns or templates. Slide the curve up and down along the work piece until the desired curve is found. Then trace around the curve with a pencil or marking knife (I generally use a pencil, since a marking knife can cut and nick the plastic). French curves can also be used to lay out ovals (inset). Here again, position the curve until the desired shape is obtained, and trace around it. A pair of light pencil marks on the curve will help you align it for the remaining quadrants.

FLEXIBLE CURVES

A flexible curve is basically a lead rod that's cov­ered with a vinyl sheath. This clever lay-out tool can be bent into small, graceful curves and is especially useful for reproducing a curve from an existing part, such as pressing it around a cabriole leg that you want to reproduce. Flexible curves can be found in most woodworking catalogs and at most any art store.

Trammel Points

Trammel Points

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Trammel points (also called a beam com­pass) come in handy when you need to draw a large diameter circle or arc. Trammel points are a set of steel points that can be mounted on virtually any length beam, as long as it's straight. The heads are held in place by tightening a knurled knob on top of each trammel point. Some versions include an acces­sory head that accepts a standard pencil, in case you'd prefer a pencil line to a scribed line. Bridge City Tool Works (www.bridgecitytools.com) manufactures a gorgeous tool (inset) that features a beam with a built in metal rule.

Basic use

Just like the panel gauge, trammel points require two hands for use. One hand holds one trammel at the pivot point, while the other hand moves the opposite head in a graceful arc or circle to mark the work piece. Keep the points razor sharp and you'll need to apply only light pressure to mark your work piece.

Stick trick

If you don't own a set of trammel points and need to draw a large diameter arc or circle, try this crude but effective substitute. Simply drill a pair of small holes the desired distance apart in a thin stick. Use an awl or a brad to temporarily hold one end at the pivot point, and insert a pencil or awl in the other hole to scribe or mark the arc or circle. Naturally this isn't anywhere near as accurate as a good set of trammel points, but it'll do in a pinch.

LARGE ARCS WITHOUT TRAMMELS

Sometimes, you may find that you need to draw a large arc that exceeds the ability of your trammel points, or that would require a really long beam, or you just don't have trammel points. In cases like these, try one of the variations of the old "bent stick" trick described below.

Bent stick

The boat builder adage "If it looks fair, it is fair" certainly applies here. Just grab a thin strip of wood that's long enough to create the desired arc, and have a helper flex the stick from start point to finish. Once the desired arc is obtained, draw along the wood strip with a pencil to mark it on the work piece.

Plexiglass strip

One disadvantage to using a wood strip is the grain of the wood can and will affect how the strip flexes often in an uneven arc. You can get around this if you've got some thin plexiglass handy. Since the plastic doesn't have any grain, any arc you flex in it will be perfectly smooth.

Clamp trick

It never seems to fail that whenever I need to use a bent stick to draw an arc, there's nobody around to help. When this occurs (and the arc is small enough), you can use a pipe clamp or bar clamp to flex the stick. This leaves your other hand free to transfer the arc to the work piece.

Center Finders

Center Finders

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Finding the center of a work-piece is a common layout task. It's so common that a number of tool manufacturers make plastic center finders, like the one shown in the top photo, specifically for this task. These simple tools have lips on two adjacent sides to quickly position the work piece.

Basic use

To use a center finder like the one shown here, press the edges of the work piece up against the lips of the center finder. Then butt a pencil or marking knife up against the center cutout and draw along this to mark a line on the work piece. Next, rotate the work piece 90 degrees and make another mark. Where the lines intersect is dead center.

SHOP-MADE CENTER MARKER

In addition to finding the center of a work piece, you 11 often need to find the center on the edge of a board. The simplest and most accurate way I've found to do this is to make your own center marker. This is nothing more than a scrap of wood with a pair of dowels (or better yet, steel pins) and a hole in it for a pencil. The challenge is locating the pencil dead center. To do this, start by marking out and drilling the dowel holes (or use short lengths of 1/4" steel rod). Then install the dowels with glue (or epoxy for the metal rods). Now use these to locate dead center. Simply place a metal rule on edge between the dowels on a diagonal and make marks in both directions. Drill a hole for the pencil where the lines cross.
NOTE:
For maximum accuracy, size this hole to accept a mechanical pencil.

Dial And Slide Calipers

Dial And Slide Calipers

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Thought of mostly as machinists tools, dial and slide calipers can be quite useful in the woodworking shop. Although you rarely need to measure in thousandths of an inch, these precision tools are great for measuring small parts and checking the thickness of a work piece. Slide calipers are not as easy to read as dial calipers. Whoever came up with the idea of adding the dial deserves a medal, in my opinion. The bodies of slide calipers are usually metal, where as you can find dial calipers with either metal or plastic bodies. The latest in calipers takes advan­tage of digital technology and offers a numeric readout (though these can be quite pricey).

Thickness

I've been using dial calipers for years to measure the thick­ness of stock. I use one so regularly for this that it resides in my planer stand. Once you get used to using one of these, you'll wonder how you ever lived without it. Look for one with a dial that has1/64" measurements as well as thousandths.

Depth gauge

Most dial and slide calipers can also be used as very accurate depth gauges. Just position the end of the caliper over the hole to be measured. Open the sliding jaw until the rod on the end of the caliper bottoms out in the hole; then read the dial.

Dividers And Calipers

Dividers And Calipers

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A spring divider differs from a com­pass in that both legs hold metal points instead of a single point and a pencil or pencil lead. The legs of the dividers are opened or closed by adjust­ing a knurled nut on one of the legs. Although you can use dividers to scribe circles or arcs, they are more commonly used for layout to "divide" (hence the name) or step out equal distances, often referred to as stepping off a measure­ment.

Stepping off measurements

Once you've set the dividers to the desired setting, you can easily "step off" equal measurements along a line by "walking" the dividers along the line. Simply pivot the dividers as you go by holding the post between your finger and thumb and moving the dividers from one point to another.

CALIPERS: INSIDE AND OUTSIDE

At first glance, a caliper looks very similar to a set of dividers. On closer examination you'll find that the difference lies in the legs. On a set of inside calipers, the legs bow in (photo below right); with outside calipers, they curve gently out at the ends (photo at left). Calipers are used primarily to take accurate inside and outside measurements so that these can be

transferred to another layout or to reproduce a part. If you practice holding the caliper so that your fingers can adjust the knurled knob, you can set it with one hand, leaving the other hand free to steady the work.

Compasses

Compasses

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A compass is useful in the shop for laying out circles and arcs. The most common types are the bow compass and the wing compass. The bow compass is a drafting tool with a threaded shaft that runs between the legs held together with a spring on top. One leg holds a steel point, the other a pencil lead. The legs of a wing compass are hinged at the top or joined with a spring and forced open or closed by turning a knurled knob that attaches to a threaded post that spans the legs. One leg has a steel point and the other is often designed to hold a standard pencil.

Drawing circles

I like to set my compass with a steel rule. I set the steel point into the etched graduation at the 1" mark and then adjust the drawing point to the desired radius (plus 1"). Although the steel point of a compass generally does an adequate job of holding its place, I've found that making a slight starter hole with an awl helps keep the point from wandering as the compass is rotated to mark the circle or arc.

Dividing circles

Here's a quick way to convert a circle to a hexagon or lay out six equally spaced holes (such as for spindles or mounting holes). With the compass still set to the desired radius, place the steel point on the perimeter of the circle and rotate the compass until it scribes a mark across the perimeter. Then move the steel point to this location and scribe anoth­er mark. Continue like this all the way around the circle—you'll end up where you started.

Bevel Gauges

Bevel Gauges

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A bevel gauge (or sliding T-bevel) is an invaluable layout tool in the shop. You can use it to verify angles, set tools to match angles, and lay out virtually any angle. Most bevel gauges feature a metal slotted blade and a stock or body made of wood, plastic, or metal, available in a variety of sizes. The blade conveniently slips into the slot in the body for storage. The blade is locked in place by tightening a thumbscrew, wing nut, lever, or knob at the base of the stock.

Duplicating an angle

A common use of the bevel gauge is to duplicate an angle so that you can reproduce it. To do this, loosen the thumbscrew or wing nut so it's friction-tight, and press the stock of the gauge up against the edge of the work-piece. Then angle the blade until it rests on the angled end of the work-piece. Tighten the wing nut, and then use the gauge to duplicate this angle on another work-piece.

Setting with a protractor

In many cases you'll want to set the bevel gauge to an exact angle, or read the angle you've just set (such as when you're duplicating an angle). The most accurate way to do this is to use a protractor. The critical point here is to make sure that the blade of the bevel gauge intersects the base of the protractor exactly on center. Then either adjust the blade to the desired angle, or read the angle of the blade.

Dovetail Gauges

Dovetail Gauges

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A dovetail gauge (or dove­tail marker) is a single-use tool that's designed to lay out the pins and tails for dovetail joints. Quality dovetail gauges will offer the two most common angles for dovetails: a 1:8 slope for hardwoods and a 1:6 slope for softwoods. If you generally use these two slopes, a dovetail gauge or set of markers like those shown in the top photo will serve you well (the gold marker is for hard-woods, the dark marker for softwoods). If you prefer to set your own angles, a bevel gauge (see Bevel Gauges) is a better choice.

Tails

To use a dovetail marker, first use a marking or cutting gauge to set the depth of the tails to match the thickness of the wood. Then carefully lay out the tail spacing. Position the dove­tail marker so it aligns with one of the marks and so the slope is in the correct direction. Then use a pencil or marking knife to mark the side of the tail. Flip the marker over and mark the opposite side. Continue like this until all the tails have been marked.

Pins

Depending on how you cut your dovetails (I always cut the tails first and then use them to locate the pins), you may or may not want to mark the pins at the same time you lay out the tails. Whichever method you choose, align the marker with the layout marks that you made on the end of the work-piece and mark their location with a pencil or marking knife.

Panel Gauges

Panel Gauges

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A panel gauge is basically a wood marking gauge that's designed to handle big panels. The difference is the beam is much longer (typically 15" to 30") than a standard gauge and the fence is muc h wider. In the past, panel gauges were often made of mahogany with brass wear fittings. The exquisite one shown here (top photo) is made by Bridge City Tool Works (www.bridgecitytools.com) and will mark to the center of a 48"-wide work-piece. You can also regularly find antique panel gauges on the Internet at various sites, running anywhere from $20 to $40 for a gauge in good condition.

Two hands

Using a panel gauge is definitely a two-handed opera­tion. After you've loosened the thumbscrew (older versions often use a wedge to lock the beam in position) and adjusted the pin or knife the desired distance from the edge, lock the beam in place. Then press the fence firmly against the edge of the work-piece with one hand while you apply light downward pressure to the pin or knife with your other hand. Move the gauge slowly with steady even pressure.

Cutting disc

Instead of a pin or knife, the Bridge City panel gauge shown here uses a cutting disc. The disc is made of hardened steel and is beveled to help pull the fence into the work-piece as you move the gauge along the edge of the work-piece. This leaves razor-sharp lines with no tear-out, even when your cutting across the grain.

Mortise Gauges

Mortise Gauges

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A mortise gauge has two pins instead of one to simultaneously mark out two parallel lines. It's designed specifically to lay out the cheeks of mortises and tenons. One of the pins is fixed, while the other is inde­pendently adjustable. In some cases, this pin adjusts via a simple pull slide; on others there`s a thumbscrew or knurled knob mounted to the end of the beam. Many mortise gauges also feature a third pin on the beam opposite the two mortise pins. This allows the mortise gauge to also function as a marking gauge.

Setting the pins

The first step in using a mortise gauge is to set the pins. To do this, hold the mortise chisel up to the pins, adjust the traveling pin over to match the width of the chisel and lock it in place. Then slide the fence over so the pins are set the desired distance from the edge of the work-piece. Try the setup on a scrap piece first and check the layout with a rule. Readjust as necessary.

Basic use

Just as with the marking gauge or the cutting gauge, the critical thing here is to firmly press the stock up against the edge of the work-piece. All you're looking for here is steady even pressure. Popeye-like strength will only cause problems—most commonly, excess pressure will shift the position of the traveling pin or the beam. Use a light, firm grip, and tilt the gauge away from the direction of movement.

Cutting Gauge

Cutting Gauge

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A cutting gauge is very similar to a marking gauge except that instead of using a pin to mark the work-piece, it uses a knife. The advantage to this is that the knife cleanly cuts through the wood fibers instead of tearing them, as a pin does. This makes a cutting gauge the tool of choice whenever you need to mark lines across grain.
You might then think, why not throw out my marking gauge and just use the cutting gauge? Because since the knife of a cutting gauge leaves such a thin, crisp line, it virtually disappears when you use it to scribe a line along the grain. Shop-Tip: To create a "universal" mark­ing gauge, some woodworkers file the point of their marking gauge to a finer point. This does an adequate job of marking both with and against the grain, but is still inferior to results from the individual gauges.

Basic use

The technique for using a cutting gauge is virtually identical to that of the marking gauge, with one exception: Take care to use very light pressure. If the knife is sharp (a few licks with a diamond hone will bring it to a crisp point), it's easy to cut deeply into the wood, leaving cross-grain scratches that can be a hassle to remove.

VENEER STRIP TIP

A cutting gauge can also be pressed into service to create uniform strips of veneer to use as inlay for your projects. Set the fence to the desired strip width, and place the veneer on a scrap piece so it's flush with the edge. Make a series of light cuts to produce strips.

Marking Gauges

Marking Gauges

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Marking gauges are extremely useful for marking lines parallel to an edge with great accuracy, such as when you're laying out joints to be cut. A marking gauge basically con­sists of four parts: a beam, a fence (or stock), a thumbscrew, and a marking pin. The beam and fence may be made of wood or metal. Wood marking gauges are more common and may or may not have brass strips inlaid to reduce wear. Some beams have scales, but these are best used only to set the fence to an approximate distance.

Basic use

To use a marking gauge, loosen the thumbscrew and slide the fence the desired distance from the pin. Tighten the thumb­screw and make a test mark; readjust as necessary. Place the fence of the gauge up against the edge of the work-piece and angle it so the pin tilts away from the direction you'll move the square. Although most woodworkers feel they have better control pushing the gauge, there's no reason not to pull it if this feels better to you.

Steady, even pressure

A marking gauge will accurately scribe parallel lines as long as you use steady, even pressure to hold the fence firmly against the edge of the work-piece. If you don't, the pin can and will wander. Pressing firmly will also keep the beam parallel to the surface, which will prevent the pin from scribing at an angle.

Levels

Levels

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While many woodworkers think of a level as a carpenter's tool, it has a place in every shop. A LEVEL particularly a torpedo level is handy for checking that shelves are LEVEL cabinets are hung plumb, and work­benches and tools are level.

Types of levels

The most common levels are 3 or 4 feet in length, with bodies made of wood, metal, or plastic. Virtually every level has multiple vials, which are curved glass or plastic tubes filled with alcohol (hence the name "spirit" level). A bubble of air trapped in the vial will always float to the highest point on the curve. Marks on each side of the center-point indicate level or plumb. While steel I beam style levels (center level in middle photo) are accurate and lightweight, I still prefer the warmth of the older wood and brass levels of yesteryear (top photo).

Checking a level

Can a level go out of whack? You bet. Here's how to check to make sure your level is on the level. Place the level on a known-flat surface and mark its exact location with a pencil (bottom drawing). Note the bubble reading on the vials with a pencil mark as well, and then flip the level end for end, aligning it with the pencil marks. Check the bubbles and then repeat by flipping the level upside down. All of the bubble readings should match. If they don't, most levels have adjustable vials to make this correction. Loosen the screws, adjust the vial positions, and repeat until all readings are the same.

Framing Squares

Framing Squares

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A framing square is another one of the tools that some woodworkers feel belong only in a carpenters toolbox. That's too bad, because a framing square is quite useful in the wood-shop. The longer legs of a framing square make it ideal for checking larger surfaces, where a smaller try square or combination square won't give an accurate reading. Framing squares can be found in a number of materials and sizes. I prefer an aluminum square over a steel one, as its much lighter and won't rust over time.

Checking a framing square

To make sure your framing square is accurate, place it on a work-piece with a known straight front edge. Position the square so the short leg (the tongue) extends just over the edge of the work-piece. Then draw a line along the long leg (the blade) and flip the square over. Slide the square over until the blade aligns with the line you've just drawn—it should line up perfectly. If it doesn't, you can re-true the square by lightly hammering the metal at the diagonal joint between the tongue and the blade. If you hammer on the inside edge, the square will "open"; hammering on the outside corner "closes" the square.

Accuracy tip

Whenever you're looking for added accuracy with a framing square, allow the tongue or blade of the square to hang down over the edge of the work-piece and press it firmly against the edge. This ensures that the square will be aligned perfectly with the edge. It's easy to introduce error here if you simply try to hold the tongue flush with the edge with the square on top of the work-piece.

Combination Squares

Combination Squares

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What do you get when you combine a metal rule, try square, miter square, level, and depth gauge into one tool? A combination square. A combination square is a metal rule with a groove in it that accepts a pin in the head of the square. The head has two faces—one at 90 degrees and the other at 45 degrees. When the knurled nut on the end of the pin is tightened, the head locks the rule in place at the desired location. Some heads also incorporate a spirit level, but the short length of the head (typically 4") limits its usefulness. While most combination squares come with only one head, there are two other accessory heads that are quite useful: a center-finding head and a protractor head that adjusts to any angle from 0 to 180 degrees (inset).

As a try square

Probably the most ordinary use of a combination square is as a try square. The advantage to using a combination square is that you can adjust the blade to the desired length. Also, since its head is metal, a combination square is usually more accurate than a try square with a wood stock.

As a depth gauge

Another frequent use of a combination square is as a depth gauge. To use one for this purpose, loosen its knurled knob and place the 90 degree face of the head so that it spans the hole to be mea­sured. Make sure all chips are cleared from the hole, and then lower the blade until it bottoms out. Tighten the knurled knob and remove the blade to read the depth.

Parallel lines

By far the most common reason I reach for a combination square is that I need to mark out a line parallel to an edge or a series of parallel lines. The combination square really excels here. Say, for instance, you want to lay out a series of lines on a fireplace mantel where you're going to carve a set of flutes. Just set the blade the desired distance from the edge of the work-piece, lock it in place, and then butt the head up against the edge of the work-piece. You'll note that there's a small notch centered in the end of the metal rule; this is for your pencil (or awl, if you prefer). Position the pencil in the notch, and while holding it firmly in place, slide the square along the edge of the work-piece, keeping steady pressure on the head.

PARALLEL LINES WITHOUT A COMBINATION SQUARE

If you don't have a combination square and need to lay out parallel lines, here are a couple of ways to do it. I had an old-timer woodworker friend who could mark out parallel lines with just a pencil with unbelievable accuracy. He'd hold the pencil in his hand and use his fingers as a stop to position the pencil where he needed it (top photo at left). He'd been doing this for so long, he could hit a mark within about V32". Although I'm not that accurate, I often use this method when I'm marking out a detail that doesn't require absolute precision, like the chamfer around the edge of a table top.

If you've got a lot of parallel lines to draw that need to be precise, consider constructing a simple shop-made square (bottom photo). It's just a block of wood that's notched the desired dis­tance in from the edge. A kerf in the end of the scrap accepts a pencil to draw uniformly accu­rate lines.

CENTER-FINDING TIPS

You'll frequently need to find the center of a work-piece. The combination square is the per­fect tool for the job. Here are three different ways to use it to locate dead center.

Marking diagonals

The first and simplest method to locate center is to use the 45-degree head of the square to mark a series of diagonals. This method works best with stock that is relatively square, since sides that are not 90-degree can throw the center-point off.

Using a center-finding head

If you've purchased the center-finding head for your combination square, it doesn't get any easier than this. Just slip the center-finding head on the blade and position the head so it touches adjacent sides of the work-piece; then mark center. This head is especially useful for finding center on round stock.

With a framing square

The only disadvantage to the methods described above is that they work well only for relatively small work-pieces. If you have a work-piece that's larger than 6" to 1", you might find that this tip works well: Clamp a framing square to the blade of the combination square so that the long blade butts up against the 45-degree face of the combination squares head. Adjust the blade of the combination square so that it bisects the inside corner of the framing square. Then position the framing square so that both its legs contact the work-piece, and mark the center.