Popular Woodworking 2004-10 № 143, страница 65

The Problem: The Holddown

All mortisers have a fence running from left to right behind the bit. The fence can be adjusted forward and back to orient the mortise location directly under the mortising chisel. Then the fence is locked down.

To keep your work held in place while mortising, you can clamp it to the fence. Or you can secure it using the holddown, which keeps the work from lifting off the table when you pull the tooling out of the cut. After each plunge, you need to shift the work left or right to make the next hole.

Having to unclamp, move and reclamp the workpiece before drilling each hole takes a long time. And many holddowns on mortisers have design shortcomings that cause them to slip during use, ruining your work.

The Solution: An X/Y Vise

Enter the cross-sliding (or sometimes called X/Y) vise: this nifty device allows you to hold the workpiece firmly in place but still be able to easily move it under the mortising chisel.

Originally designed for work on metal milling machines, cross-sliding vises allow the operator to clamp a workpiece tightly below the spindle (or, in our case, the chisel) then smoothly move the piece forward and back, as well as side-to-side, without having to release the work from the clamp.

Many floor-model mortisers have these vises built in, but these big machines can cost $800 or more. But we've found a $50 upgrade that can be added to almost any benchtop mortiser. Ifyou don't have a mortiser, you can also use it to upgrade your drill press and use

overlapping holes to effortlessly create your mortises.

Is it too good to be true? Well, almost. There are some technical difficulties to overcome before you decide if this vise belongs in your shop.

Problems with the Solution

First, as you'll note in the picture below left, there are three operational handles on the cross-sliding vise (X-axis, Y-axis and clamping handle) located on three of the four sides. The non-handled side is the one facing the column of the machine. This keeps the clamping vise oriented front-to-back so that if it is holding a table leg, for example, the leg will jut straight out from the mortiser. This orientation, which is at a 90° angle from the way a mortiser is usually used, puts the part in an awkward loca

tion during mortising. But that's only one problem.

The next hurdle is height. As shown in the photo below right, benchtop mortisers come in a variety of heights. The Shop Fox is designed to allow the motor to raise 12" above the table. This allows 8" below the chisel for the cross-sliding vise (shown attached). The Fisch mortiser (on the right) and most other benchtop mortisers available on the market today allow only 4" of space between the table and the tip of the chisel, leaving no room for the vise.

Combo Solutions

We've come up with a couple of options to solve both of these problems. First, by buying two separate metalworking accessories and combining them, the

While you can use a cross-sliding table mounted in this position on the mortiser, it's an awkward reach. With the project pointing straight at your stomach, you can't adequately operate the machine. Beyond that, any intermediary mortises will require the workpiece to slip between the posts on this mortiser and will be blocked by the center post on other mortisers.

These two mortisers quickly make the height difference apparent. The Shop Fox, left, has longer columns and is capable of being adjusted to gain additional height by relocating the gas cylinder on optional pins.

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Popular Woodworking October 2004