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Woodwork 

Winter 2013-2014

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Turned Knobs

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Turned Knobs

Dress up your furniture with custom knobs.

By Alan Lacer


Why would you ever make your own knobs when you can buy them for less than a buck? I can think of several reasons—limited choices of wood, for example. Many knobs are only available in oak or birch. But perhaps the best reason is aesthetics. Most production knobs look pretty plain, due to the constraints imposed by mass production. It’s a shame to saddle your furniture or cabinetry with run-of-the-mill knobs when it’s easy to enhance your work with knobs that are hand-turned and finely detailed. Plus, there’s the undeniable satisfaction you get from making your own knobs.

Knob-making is a great exercise in understanding grain orientation and how to work with it. The face of a knob can show either end grain or face grain. End-grain knobs (also called “long-grain” knobs) are turned with the grain oriented parallel to the lathe’s bed, as in spindle turning. Facegrain knobs (also called “short-grain” knobs) are turned with the grain oriented perpendicular to the lathe’s bed, as in most bowl turning.

The tools you’ll need for turning both types of knobs include a detail/spindle gouge, a parting tool and a skew chisel.

 

End-Grain Knobs

End-grain knobs are strong because the grain runs lengthwise through the knob. This makes them the best choice if you want to turn slender shanks with delicate shaping and fine detailing. End-grain knobs usually have tenons on the ends rather than being fastened with screws, because screws that are threaded into end grain don’t hold well.

Although end-grain knobs are oriented the same way as spindle work, you shouldn’t mount the blanks between centers. Instead, provide clear access to the face of the blank by mounting the stock in a scroll chuck. You can easily chuck a blank that’s long enough to turn several knobs— just allow sufficient length for mounting and for waste between the knobs.

Once the blank is mounted, turning an end-grain knob is fundamental spindle work. Start by establishing the knob’s diameter (Photo 1). Then shape the knob’s face by cutting from large to small diameters (Photo 2). Use a skew to add details (Photo 3). Shape the shank to create a finger recess (Photo 4). Again, work from large to small diameters. Finally, turn the tenon to fit the hole drilled in your door or drawer (Photo 5).

 

Face-Grain Knobs

Face-grain knob shanks must be larger in diameter than end-grain knob shanks, to compensate for their grain orientation—these knobs are likely to break at the shank, due to the short grain, if the shank is too slender. I seldom go below 1/2" dia. behind the face.

On the other hand, the faces of face-grain knobs show face grain, so they match the fronts of drawers and doors better than the faces of endgrain knobs. Face-grain knobs are also a better choice when the wood is going to be stained, because their faces take stain more evenly.

A screw chuck is the best device for mounting a face-grain knob blank. This chuck has the added benefit of creating a centered screw hole for mounting the knob (face-grain knobs attach securely with screws). I attach a shop-made drawbar to prevent the chuck from popping out during operation.

It’s best to turn face-grain knobs one at a time. Using stock milled flat and slightly thicker than the pulls’ desired height, cut out a series of blanks, including one or two extras, just in case.

Face-grain knob-turning resembles bowl turning, because the grain runs at a right angle to the lathe’s bed, just like a bowl blank. You will quickly discover that cutting coves and fine detail on the side of a facegrain knob is more challenging than it is on an end-grain knob. That’s because the side alternates between end grain and long grain as it rotates. On the other hand, detailing the face of a face-grain knob is much easier than it is on an end-grain knob.

To turn a face-grain knob blank into a cylinder without chipping the ends, start your cuts from off the blank at both ends and meet in the center (Photo 6). Because of the blank’s weak short-grain structure, turn the knob’s face first. (If you turn the shank first, it may break while you’re turning the face.) To create fine convex and concave details, treat the face as if it were a small bowl (Photo 7).

Once the face is complete, you can address the side of the knob. Here’s where things get a little tricky: Because of the side’s short-grain structure, you have to work from small to large diameters—the opposite of normal spindle work (Photo 8). Add fine details with a skew chisel (Photo 9).


Source

(Note: Product availability and costs are subject to change since original publication date.)


This story originally appeared in American Woodworker October/November 2008, issue #138.

October/November 2008, issue #138

Purchase this back issue.

Click any image to view a larger version.

To turn end-grain knobs, you’ll need a four-jaw scroll chuck to hold the stock. For face-grain knobs, use a screw chuck with an attached shop-made drawbar to keep the chuck from popping out of the headstock. The drawbar consists of a threaded rod (match the threads inside your screw chuck), a wood spacer, a washer and nut.


Turn an End-Grain Knob


1. Start an end-grain knob with a blank mounted in a scroll chuck. Establish the knob’s diameter with a parting tool and outside calipers. Make sure the caliper points are rounded and smooth, so they won’t catch.


2. Shape the outside face of the knob, using a detail/spindle gouge. Work from large to small diameter.


3. Detail the knob’s face with the long point of a skew chisel. Most woodworkers avoid working with end grain, but turners know it presents unique possibilities.


4. Create a finger recess between the knob’s head and base, using the gouge and working from large to small diameters. End-grain knob shanks can be turned to slender diameters.


5. Size the tenon with the parting tool and outside calipers. Go slow and make sure your calipers are set for a perfect fit. Accurate sizing is essential for a strong joint.


Turn a Face-Grain Knob


6. Mount face-grain knob blanks on a screw chuck. Turning these knobs takes a light touch, as heavy cuts can strip the screw hole. Start by creating a cylinder. Work from the ends towards the middle to avoid chipping the outside corners.


7. Detail the knob’s face with the detail/spindle gouge. This work is similar to turning a small face-grain bowl: Work convex areas from small to large diameters and concave areas from large to small diameters.


8. Create the knob’s shank by working from small to large diameters. Face-grain knobs require a different technique than endgrain knobs, as cuts are made in the opposite direction.


9. Crisp detailing separates handwork from production pieces. The long point of the skew adds fine details and crisp lines that emphasize transitions between concave and convex shapes.


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