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'/«■inch-diameter bit. If you want a '/¿-inch-wide mortise, use a '/^-inch-diameter bit. In this instance, of course, the mortise is to be I1/« inches wide, and it's unlikely you have a straight bit of that diameter. The largest straight in my collection is 1 inch in diameter.

But with a template, you can easily use a '/»-inch or '/>inch bit to produce this mortise.This is because the template, not an edge guide, controls the cut. Instead of making a single straight-Line cut, you rout around the inner perimeter of the template, then rout back and forth or end lo end to remove the interior waste.

A significant consideration in choosing a bit is the impact the bit diameter has on the mortise's corners. A large-diameter bit hogs out the waste quickly but leaves a substantial web of waste to be- removed with a chisel. If you use a small-diameter bit—say, a '/»-inch bit—that web of waste is much smaller, much more easily removed.

The final consideration, and it's a vital one, is the bit's overall length.Tally up the needs: a minimum of x/i inch in the collet + the router base thickness + the thickness of the template + the desired mortise depth. To rout a through mortise in 5/4 (five-quarter) stock using a '/«-inch template means the bit must be a minimum of 2 inches long.

In this Instance, I selected a '/«-inch-diameter bit.

2. Choose the template guide bushing. In sdecting the guide bushing, there are two facets that must be considered: the collar diameter and the collar length.

Perhaps obviously, the inside diameter of the collar must be large enough to accommodate the bit. But you should also consider chip clearance. Using a large-diameter guide bushing with a small-diameter bit provides plenty of clearance for the chips that well out of the cut. If you can manage it, allow at least Vi6 inch between the bit and the inside of the collar, wliich means that the inside diameter of the bashing should be Vh inch larger dian the bit diameter. An example: For a '/i-inch-diameter bit. use a %-inch-O.D. bushing, which typically has a 2l/32-inch inside diameter.

In addition, choose a bushing with a short collar so you can use a thin template. The collar, as you probably know, must be just a skosh less dian the template thickness. And the thickness of the template has to be subtracted from the maximum reach of the bit at full plunge, thus limiting the depth of the mortise that can Ik- routed. If your mortise must be more than 1 inch deep and your template is inch thick, you are going to need an awfully long bit. Every fraction of an inch you shave off the template pushes the mortise deeper.

The hitch, of course, is that large-diameter guide bushings tend to have long collars. A visit to the bench grinder can cut the collar down to a more reasonable length.

For the mortising template shown, use a 3/t-inch-O.D. guide bushing, and make sure the collar is no more than Vi inch long.

3. Select and cut the template stock. The template-stock. as noted earlier, can be hardboard, MDI\ plywood, or

CHOOSING A BIT FOR TEMPLATE-MORTISING

K"-O.D. bushing Edge of mortise

Edge of template

K"-O.D. bushing Edge of mortise

Edge of template

BIT DIAMETER

Large-diameter bit clears the mortise quickly, and leaves wide-radius corner.

Feed direction

Waste left after first pass

BIT LENGTH

Large-diameter bit clears the mortise quickly, and leaves wide-radius corner.

Feed direction

Edge of mortise Edge of template

Small-diameter bit requires more passes to clear the mortise, and leaves tight-radius corners.

Feed direction

Waste still to be routed away

Portion of bit in router collet Baseplate/guide-bushing thickness Template thickness

Workpiece thickness Scrap

/ VA"

A

TEMPLATE-MORTISING SCHEMATIC

To the length (or width) of the mortise add twice the offset to determine how long (or wide) the opening in the template must be.

plastic. With the length of the guide bushing's collar in mind, check the scrap bin for a usable piece. Failing there, use the least expensive of these materials for your template. This is especially true if the template will be job-specific— that is. made for this particular job and destined for the scrap bin when that job is completed.

For the generic template under consideration here, I \ used 'A-inch birch plywood. It's a material 1 had on hand.

and it is light-colored, so layout lines show up easily. MDF » (medium-density fiberboard) in a '/»-inch or Va-inch thick-ness is an excellent material, as is any good-quality plywood in cidier of those thicknesses. Hardboard is suitable, but I find it next to impossible to see layout lines drawn on it, so Ol I generally avoid it for applications like this.

Roughly size the template material, making it large enough that clamps can be applied where they won't interfere with the router's movement around the template window. The Cutting List specifics that this template be 12 X 16 inches.

4. Lay out the window on the template stock.

The guide window is the opening into which the guide bushing fits. With the bushing trapped in that window, the router's movement is limited. In essence, it can move from one end of the window to the other, from one side to the other, because the bit is inside the bushing, its range of movement, too. is limited.

The task now is to design and lay out the slot necessary to produce the desired mortise. To start, note the width and length of the desired mortise (in this instance, a 1 '/»inch-wide. 2V»-inch-long one). You've already chosen a inch-diameter straight bit and a '/«-inch-O.D. guide-bushing. Compute the offset, which is determined by subtracting the bit diameter from the bushing diameter and dividing by 2. In this case, the offset is '/i inch.

Here's how to translate the dimensions of the desired mortise into the dimensions for the necessary template slot. Add twice the offset to the mortise length, as shown in the drawing Template-Mortising Schematic. Tints, the

Routing the template window is a straightforward operation. The ¡/4-inch-thick template material is clamped to scrap. The window's length is controlled by the stops clamped to the template material. The router's edge guide positions the window.

template slot must be \ % inches wide and 3'/» inches long.

Follow the drawing Generic Mortising Template iMyxmt. Scribe the centerlinc of the slot, then add a! crosshair at the midpoint. Because these lines will be used again and again to position the completed template oa workpicccs, the lines should be drawn with a pen or fine line marker. Then lay out the window from these lines, (lf| you have trouble seeing your layout lines on hardboard—ij always do—try applying strips of masking tape to the hanJ-j board.T hen pencil the layout lines on the tape. When von: rout, just rout through the tape.)

5. Rout the window in the template stock. A:

very easy and accurate way to cut the guide window iij with a plunge router equipped with an edge guide.You do have to reset the edge guide to gel all the waste, but both! long edges of the window will be parallel, because botharc| referenced from the same edge of the template.

To begin, dog or clamp a piece of scrap of the wotfc bench, then clamp the template to it. Arrange the template so the edge you will reference with the router's edge guide projects beyond the scrap's edge. You want to refer-1 ence the template edge exclusively with the edge guide. (You could also screw the template to the scrap; two or| three holes in it won't interfere with the use of the! template.)

Tighten a straight bit in the router's collet. Set the! plunge depth to just a skosh more than the template t ness. Install the edge guide, and adjust it so the bit will one edge of the window, just leaving the layout lin^ Before routing, set up a pair of stop blocks to prevent \ from overshooting either end of the slot.

With the blocks set, rout the first slot. Set the on the template, switch it on, plunge the bit. and routfi stop to stop. Reset the edge guide, then make a se pass, widening the window. Repeat the process until tbt] window is completed.

Workpie Offset

Mortise length

Offset

1. Set up the router. Stan by fitting a %-inch guide bushing into die bit opening in the router baseplate. Next, tighten a '/»-inch straight bit in the collet. A spiral

Three templates in one makes for easy storage. On the 12 X I 5-inch piece of '/^-inch plywood (resting on the bench) are the patterns for all the template-guided cuts made in constructing this five-board bench.

The completed mortise is clear* and accurately sized and positioned.

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Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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