Brace drills, also known as bit braces, can be traced back to the early 15th century and their use by carpenters in Europe. The brace drill has it’s handle offset to the axis of rotation. Before they were introduced, carpenters drilled holes in wood by turning augers or gimlet bits in repeated rotations via handles.
The brace drill enabled continuous turning and made for quicker boring of holes. Early drills used low efficiency bits of shell or spoon shape; screw shaped auger bits first appeared around 1800. Also slow to develop was the modern springed-jaw chuck with it’s screwed shell, which came in around 1865.
The brace consists of a frame made of steel, on which the handle is mounted, with the chuck and bit at one end, and a second handle, the head, at the other end. A clockwise turning force is applied to the first handle with one hand, while the second hand holds the head handle in place. The handle sweeps around the axis of the chuck and bit, and the diameter of the sweep gives the size of the tool. Brace drills are available with sweeps of 5, 8, 10, 12 and 14 inches.
In some braces, the chuck has a ratchet mechanism to allow for use in confined areas, for example, when drilling holes in baseboard molding, where there is insufficient space for complete sweeps of the handle.
The ratchet is activated by turning a cam ring clockwise until it hits it’s stop. When ratcheting is engaged, the handle will only provide torque to the bit when turned in the clockwise direction; it will rotate freely counter-clockwise. The reverse effect can be achieved by turning the cam ring counter-clockwise until it hits a second stop.
Another type of brace drill, the corner brace, can be used for drilled holes in confined areas. It has a regular brace frame which is fitted to a gear housing and second frame at a 45 degree angle. Also known as a gear frame brace, it can come in 8 and 10 inch sweep sizes.
Using a Drill Brace
To drill a horizontal hole, locate the bit on the workpiece, using either a small pre-drilled pilot hole or pencil marked cross-hair. Hole the head of the brace with one hand, using your body weight as pressure, and hold the handle of the brace with your other hand. Make sure the drill bit is 90 degrees square to the work surface. Turn the frame clockwise with a steady motion.
For drilling a vertical hole, use the same technique while placing the tool axis straight up and down. If you clamp a carpenter’s square near to your hole you can more easily gauge your hole’s angular alignment.
Deeper holes need to have waste and sawdust cleared out of them while drilling, so you’ll need to remove the bit a couple times during the drilling for this. Turn the handle in a reverse direction (disengaging or reversing the ratcheting if required) a couple of turns while pulling the frame out.
The joist brace is another type of brace drill for use in restricted areas, in this case in between floor joists or roof joists. It has the same ratcheted chuck and handle construction. However, in place of the offset frame handle, it has a lever placed at a 90 degree angle to the axis of the chuck, with a handle on it. The bit is turned by working the handle back and forth; pressure is applied via a second handle at the end opposite the chuck.
Other than infrequent oiling of the chuck and ratcheting areas, today’s drill braces are largely maintenance free; they are a rugged and long lasting addition to your woodworking tool collection. Cordless power drills are handy, but manually operated hand drills like the brace drill come in handy when working in remote areas without power or when you want to keep quiet.
Photo by Dan McKay, Creative Commons Attribution License