Templateguided Work

A template is a quick and easy way to duplicate shapes like circlcs, squares, or even ktters. That's one of its primary uses, but there are others. Many others.

The typical template is a durable wood or plastic or metal pattern. When the router, fitted either with a guide bushing or a pattern bit, is run along the edge of the template, the bitmakes a cut in the exact contour of the template. So when remarkable consistency from pan to part is required, a template is used to guide the cuts that produce the parts.

Commercial dovetail jigs, for example, depend on guide bushings or pattern bits to guide the cuts. Every piece has to be reproduced accurately and consistently if the dovetails are to come together successfully. The template system virtually guarantees that they will.

In a production setting, templates are used to create stacks of identical pans. You can consistently contour the edges of workpieces by damping a template to the rough-sawn pan and then guiding the router along the template. Its bit will machine the workpicce to the same contour as the template. And every part cut using the template will be identical.

Now you may not need to produce stacks of identical parts, but if you want to make just eight identical back legs for a set of four chairs, it's worth the trouble to make a template. In fact, yrou may make a template just to scribe around so you can cut them on the band saw.

Why not spend an extra half hour to make that template precise, then guide the router around it, shaping each leg to the exact contour you want. You can even cut out a window in the template so it can guide the router when you rout mortises in the legs.

Templates can be used to guide joinery cuts other than dovetails and mortises. You can rout the edges of two boards along complementary curves, so they can be edge-joined perfectly. You can use a template to guide dado and grooving cuts, to cut laps, and even to control a miter-gauge-like jig for cutting box joints on the router table.

Perfectly fitted inlay work is done with relative ease using a router and a template.

Once ycu try any of these techniques, you'll realize how easy and reliable template-guided work is. The potential is tremendous.

THREE SETUPS

There arc three common template systems in the home shop. The first is designed to guide a round-based, hand-held router. The second uses a guide collar or bushing attached to the base of the router. This collar guides the bit along the edge of the template. The third system uses a flush-trimming type of bit with a bearing on the shank (instead of the bit tip. as is commonplace). (A fourth system, used mostly in industrial applications, utilizes a pin guide on the side of the stock opposite the router.) There are pluses and minuses to each system.

There sometimes is confusion arising from the names given to the piece against which the bushing or bearing or pin rides. Sometimes it's called a template, sometimes a pattern. Technically, a pattern is an original part or a piece that, though different in material and thickness, is exacdy the same size and contour as an original. The template, on the other hand, is simply a guide used to produce an original, and it may or may not be the same size and contour as an original. Fred and 1 both tend to use the term template more often than not, even when we mean a pattern. (1 suspect that tendency will prevail throughout this chapter.)

To cut a hole in a counter for a sinh, use a framelike template to guide the router base. An advantage to this approach is that the template's edge need not be perfectly smooth, since the base tends to ride over minor irregularities without telegraphing them into the cut. Moreover, because the template is beside, rather than beneath, the router, it doesn't steal any cutting depth from the tool.

Guiding the Base

The first guidance system allows the router 10 ride directly on the stock surface. This not only affords the best support and accuracy of depth but also allows you to cut with the full length of your bit's cutting edges, rather than having to reach past the thickness of a template.

A less obvious advantage to this system is that the template needn't be finely finished. The large radius of the router base can ride a neatly band-sawed edge without translating every little saw mark into the cut. But this also means that it smooths out details.

The need to scale the template to the size of the router's base can be a drawback, though. You can't, for example, cut an inside corner tighter than the radius of the base. The template has to be bigger or smaller, by the radius of the baseplate, than the shape you want to cut. This size difference can make it nearly impossible to clamp a template to some projects.

You can moderate the scale problem somewhat if you can use a laminate trimmer for your cut instead of a full-sized router. The trimmer usually has a baseplate diameter in the 3/2-inch range, rather than the 6- to 7-inch range.

Using Guide Bushings

Let's take a look at guide bushings. This is what most woodworkers think of when template-guided work is discussed.

A guide bushing, sometimes called a template guide, is a lot like a big washer with a short tube stuck in it. The bushing fits into the bit opening in the baseplate, and the bit projects through the tube. In use, the tube—called the collar— catches the edge of the template and rides along it. And the bit that's jutting through the collar makes a cut that, though slightly offset from the template, matches the template perfectly. You'll find that details transfer better with the collar-guided system than with the base-guided system.

While many router manufacturers provide a guide-bushing system peculiar to their routers, some have simply adopted the popular Porter-Cable system. In this design, the ring of the bushing drops into a rabbet around the bit opening so it will be flush with the baseplate surface. A threaded flange projects into the base, and you turn a lock ring onto it to secure the bushing in place. With this design, you can change bushings without touching the bit In fact, you may not even have to change ihc depth-of-cut setting. This is a handy feature when you're doing inlay work. A big plus with this universal design, to me. is that you can buy guide bushings from a variety oft sources. You aren't limited to the range of sizes the router manufacturer makes.

A guide bushing is a short tube with a flange that fits into the router base. This assortment of guide bushings gives you an idea of the range of sizes available, as well as the different mounting systems. Some bushings are attached to the router base with screws (bottom right); these are usually required on plunge routers. Bosch's newest plungers have bayonet-mount bushings (top right). The most common "universal"system uses a threaded loch-ring to hold the hushing in the baseplate's rabbeted bit opening (left). Freud's set even includes an adapter ring so you can use these universal bushings in routers that have a screw-mount design.

A guide bushing is a short tube with a flange that fits into the router base. This assortment of guide bushings gives you an idea of the range of sizes available, as well as the different mounting systems. Some bushings are attached to the router base with screws (bottom right); these are usually required on plunge routers. Bosch's newest plungers have bayonet-mount bushings (top right). The most common "universal"system uses a threaded loch-ring to hold the hushing in the baseplate's rabbeted bit opening (left). Freud's set even includes an adapter ring so you can use these universal bushings in routers that have a screw-mount design.

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With some other systems, you attach the guide bushings to the base or baseplate with screws. Some plunge routers have guide bushings thai attach with screws to a reducer that is in turn screwed to the base. The bushing drops into place from inside the base.

Bosch has a bayonet system on their newest plunge routers. Push a button on the edge of the base to mount and release the bushing. Obviously, you have to buy bushings made specifically for that model.

With all systems, the guide collar extends '/«inch or so below the base. You must use a template at least as thick as the collar is long to avoid having it drag on the work-piece's surface.

Some guide bushings are made for use with specific accessories the manufacturer also sells. Porter-Cable, for example, has odd-sized bushings to use with stair-mortising and hinge-monising templates. On some of these, the collar projects %> inch ormore. which dictates that you use it with a template Y* inch thick or

WJim routing with a guide bushing, (he bushing rides against a template on top of the workpiece. The template must be offset by the difference betneen the bit and bushing diameter s.

more. Or you can, of course, grind down the collar to reduce its length.

The size of the bushing is determined not by the overall diameter, which is usually constant, but by the inside and outside diameters of die collar. You have to use a bushing with an inside diameter (I.D.) larger than the diameter of your bit. In some cases, you can manage to use a collar that's the same outside diameter (O.D.) as the cutter—if you're using a dovetail bit, for example, or if the entire body of the bit is beyond the collar and only the bit shank extends through it. But most of the time, you'll find yourself using a collar that's at least'/«inch bigger than the cutter.

The table below lists some common guide bushing sizes. You'll see that there arc limits to what's available.

You have to figure the offset into the size and shape of your template. The template cannot be the same size as the finished piece. Here is the formula for calculating the offset:

Bushing diameter -

bit diameter — Template

2 offset

Here's an example: If you arc using a Winch-diameter bushing and a Va-inch-diameter bit. the template offset should be Mo inch. Remember, you've got to add the offset to each guiding edge of your template. In this example, to rout a I-inch by 3-inch mortise, you'd need a template slot thai measures IV« inches by 3vh inches.

WJim routing with a guide bushing, (he bushing rides against a template on top of the workpiece. The template must be offset by the difference betneen the bit and bushing diameter s.

Outside Diameter

Inside Diameter

Collar

Manu

(O.D.)

(ID.)

Length

facturer

Mo"

w

P-C, Freud

w

Mo"

P-C. Freud

Mo"

w

w

P-C. Freud

yi"

Mo"

P-C. Freud

ys"

w

Mo"

P-C. Freud

w

Mo"

P-C. Freud

1"

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P-C

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iv

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P-C

Because of the need to accommodate the offset when laying out the template, setting up for template-guided routing docs take extra time. If you have only one or two pieces to shape, and the precise contours aren't all that important, it may not he worth the effort. But routers can do very precise work when guided by a template. You'll find, therefore, that when you have an especially fancy or intricate cut to make in an expensive piece of stock, it 's worth spending the time to make a very precise template for only one use. It's not uncommon to spend several hours making the template, and only a couple of minutes making the actual cut.

Using Pattern Bits

This simplest form of template-guided routing is done with cither a Hush-trimming bit or a pattern bit. Both have pilot bearings whose diameter matches the diameter of the bit. On a flush-trimming bit, the bearing is at the bottom of the bit. On a pattern bit, the bearing is on the shank, right above the flutes. There's no offset with these bits.

Make the template (or pattern) exactly the shape you want (limited only by the bit diameter). You don't even have to make a template in many cases. Instead, make the first of the actual pans especially carefully, then use it as the template and make as many more as you want. They'll all be the same.

When routing with a flush-trimming bit. attach the template to the underside of the workpiece with double-sided carpet tape, hot-melt glue, or clamps. The bearing rides along the template, and the cutter automatically cuts the work to match. A pattern bit works the same way.

When you're pattern routing with a flush-trimming bit, the pilot bearing rides on a pattern or template attached to the workpiece. Here, a face frame trimmer-just a BIG flush-trimmer—is being used to duplicate a finished workpiece. The writ-piece was carefully sawed and sanded to a cuned contour, then bonded to a rough-sawn blank with carpet tape. The bearing rides on the pattern, and the cutting edges trim the duplicate workpiece to match the pattern.

When you use a pattern bit, the template is placed between the router and the workpiece (with a hand-held router, this means on top of the w orkpiece). For the bit's shank-mounted bearing to ride along the template edge, the hit has to he fully extended. With a fairly thich template and a short hit,you can make most cuts in two manageable passes. On the first pass, the bearing rides on the template (top). For the second pass, remove the template and adjust the bit so the bearing rides along the surface formed by the previous cut (bottom).

BIT DRAWER

BIT DRAWER

Any bit with a pilot bearing mounted on the shank is a pattern bit. The bearing rides along the edge of a pattern, while die cutting edge trims the edge of the work or plows a groove in it.

Pattern bits are available in an ever-increasing variety. And it isn't surprising. All the bit maker has todo is add a bearing to the shank. The only limitation is that the cutter diameter has to be enough largerthan theshankdiamcterto accommodate a bearing. Aft-inch straight bit with a '/¿-inch shank can be converted to a pattern bit with a bearing. A '/¡-inch straight on the same size shank cannot.

If you flip through a current catalog, you'll find all manner of groovc-fonning profi le cutters with shank-mounted bearings.

Patient bits arc available in surprising variety. The bit on the far left demonstrates why. This '/2-inch straight bit from MLCS has a distinct shoulder between the shank and lite cutter body. Slide the Vi-inch-O.D., 'A-inch-I.D. bearing at the top onto the shank, right up to that shoulder. Add the lock collar and set it with the alien wrench. You've now got a pattern bit, and a pretty useful one at that. The '/¿-inch cutting length is excellent. Other bits with the same sort of shoulder between shank and cutler are made into pattern bits just as easily. Others shown include (left to right) Amana's '/2-inch dovetail, core-box, and V-groove bits, Byrom's 2-inch-long, V*-inch straight, Eagle America's 'A-inch long, '/2-inch dado-cleanout bit. and Amana's I-inch-long, '/2-inch straight.

Patient bits arc available in surprising variety. The bit on the far left demonstrates why. This '/2-inch straight bit from MLCS has a distinct shoulder between the shank and lite cutter body. Slide the Vi-inch-O.D., 'A-inch-I.D. bearing at the top onto the shank, right up to that shoulder. Add the lock collar and set it with the alien wrench. You've now got a pattern bit, and a pretty useful one at that. The '/¿-inch cutting length is excellent. Other bits with the same sort of shoulder between shank and cutler are made into pattern bits just as easily. Others shown include (left to right) Amana's '/2-inch dovetail, core-box, and V-groove bits, Byrom's 2-inch-long, V*-inch straight, Eagle America's 'A-inch long, '/2-inch dado-cleanout bit. and Amana's I-inch-long, '/2-inch straight.

but you attach the template to the topofthe workpiece. In cither case, you should cut the workpiece to within !4o inch of the final size before routing. Also, be aware of what is under the workpiece as you rout. Don't cut into your workbench by mistake.

Which System to Use?

Each system has its advantages and disadvantages. The more work you do, the more likely it is that you'll have occasion to use them all.

The base-guided approach is useful when great accuracy and detail aren't needed. You can knock out a template fairly quickly, since you don't have to worry too much about the quality of the guide edge.

Both guide bushings and pat tern bits offer the ability to guide far more intricate cuts. Only the diameter of the bushing or the bearing limits the curves you can follow.

In addition, both guide bushings and pattern bits can be used with table-mounted routers. This is often an advantage with small work-pieces. The template can be fitted with fences to position the blank and with a toggle clamp to secure it. Use a starting pin to help you initiate the cut. Then rout as if making a cut on a piloted bit (which is really what you are doing).

Guide bushings offer several advantages over the piloted pattern bits. Because they work in conjunction with your regular router bits, you save money: no special bits to buy. Moreover, regular bits arc available in much wider variety than pattern-guided bits. Most any groove-

forming profile bit can be used in a guide bushing, so a pattern of grooves can decorate blank panels and emphasize or outline edges. Moreover, the guide-bushing system allows you to make passes around the same template with several different bits. For example, you could run a groove around a template with a '/2-inch straight bit. then switch to a '/4-inch

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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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