![]() ![]() Make sure the rear face of the chisel is aligned with the front of the fence, and retighten it. (To avoid getting cut, use a small scrap of wood to raise it.) When it’s seated in the chisel, secure the auger in the chuck as you would any drill bit.įinally, loosen the chisel, remove the dime, and slide the top of the chisel firmly against the quill. With the chisel temporarily secured, slide the auger up through the center of the chisel. To accomplish this, the chisel goes on first, snugged up to the quill with a small spacer - a dime is perfect for this. Instead, the parts are installed such that the bit is slightly ahead of the chisel. If it did, it couldn’t bore the lead hole ahead of the chisel, chips couldn’t be directed up and out through the side openings of the chisel and, worse, the rubbing would quickly build up extreme heat, potentially ruining the chisel. Ideally, the cutting tip of the auger never touches the chisel opening. Installing the chisel is a three-step process. Once the auger distance is set, remove the dime and snug the hollow chisel firmly up against the quill. Using a Mortiser To ensure that a mortising chisel’s auger spins slightly ahead of the chisel cutting edges, use a dime as a spacer when installing or changing bits. After doing the inside, hone the flat sides of the opening to remove any burrs. Chucked into a standard drill/driver, periodically hone out the opening to resharpen the cutting edges. ![]() These look a lot like countersinking bits, but have honing edges or an abrasive surface. Hone these chisels regularly with a dedicated hollow-chisel sharpener. A dull mortising chisel not only creates splintery mortises, it also greatly increases the force needed to drive it into the wood. Mortiser chisels, like any chisels, must be sharp at all times. Mortisers also require a good deal of muscle power, and an extended period of usage can result in an arm that aches for a day or two afterward - pace yourself when mortising to avoid overdoing it. Be very careful with these, as it’s easy to unintentionally brush a hand against them when setting up a workpiece (he says with the conviction of experience). What’s more, the corners of that opening are extended downward into extremely sharp points. The first is that mortising chisels are wicked sharp all the way around the square opening. Most of the safety practices for drill presses apply to mortisers, but there are two additional things to be aware of with mortisers. Then, complete the honing by rubbing all cutting edges over a flat sharpening surface - like the diamond sharpener shown here - to remove burrs. First, use a simple sharpening bit in a handheld drill/driver to hone the inside of the bit. Mortiser Safety and Maintenance In order to be effective, mortising chisels must be kept as sharp as possible. The edges of the chisel follow right behind, with the sharp downward corners squaring up the hole. Because the auger’s cutting tip is slightly ahead of the cutting edges of the chisel, when lowered into the workpiece it creates a round hole and removes most of the waste. When lowered into the workpiece, the two parts work as a team to create a square hole. The chisel mounts to the quill, while the bit goes in the chuck. These hold-downs are typically part of a fence built into the base itself.Ī mortiser’s business end is a two-part assembly consisting of a square, hollow chisel with a very long auger nestled inside. Just as a lot of torque is needed to force the chisel into the wood, substantial holding power is needed to grip the workpiece when retracting the chisel. The feed on a mortiser, meanwhile, fully lowers the auger/chisel assembly in a single, high-torque pull to power the chisel into the workpiece.įinally, a clamping and hold-down mechanism is absolutely essential on a mortiser. Since the bit alone does all cutting on a drill press, the low-torque feed levers take a few rotations for a complete stroke. While large industrial mortisers may offer multiple speeds, those for the home shop are generally single-speed direct-drive units operating at 1,725 rpm (although a few are 3,450 rpm). And both use drill bits, although mortising bits are actually specialized augers.īut similarities end there, starting with speed. Both come in benchtop and floor versions. Both have a spinning chuck, and both have feed levers that lower and raise the chuck through the workpiece. At their most basic, hollow-chisel mortisers are mechanically and operationally the same as drill presses. ![]()
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