Sources for Plastics and Hardware

You can buy most plastics over the counter. The retailer often will cut a piece to the size you want, rather than insisting that you buy a stock sheet. And because he cuts to order, he'll likely have an assortment of odd-sized scraps you can pick through and buy cheaply.

What retailer do you go to? Look in the yellow pages under "Plastics." Most regions will have a choice of suppliers, maybe even one near you.

If you'd prefer to shop by mail, page through your woodworking tool catalogs. Most diversified tool catalogs list acrylic and polycarbonate—usually in foot-square pieces—specifically for custom router bases. A few have pieces of phenolic plastic drilled and slotted for mounting specific routers in a table. And at least one— Trendlines—sells foot-square pieces of phenolic for you to turn into your own custom baseplates.

Clearing the Throat

Factory baseplates have a throat opening sized to accommodate a template guide bushing. When you want to use a template guide, it's just the right size. But in many other situations, it can be just the wrong size.

If you arc working on a narrow workpiece. this opening is big enough that it can make it difficult to support the router, especially at a corner or the end of the piece. The danger is that as the end or corner passes underneath the throat, the router might tip, causing the bit to gouge the work. In this situation, you want the throat to closely match the diameter of the bit you're using.

On the other hand, a big bit may not fit through the guide bushing-sized throat. Here you want a BIG opening.

With your own selection of baseplates, you can tailor your equipment to the job. Make one baseplate with a Winch throat and another with a 2- to 2'/2-inch throat. Keep the factory baseplate for template-guided work.

Joining Plastics

Plastic can be joined to plastic or to wood or to metal. Use common mechanical fasteners like bolts and screws. Or use glue. Though both approaches are familiar to every woodworker, there are some novel twists in how these apply to plastics.

Take the fastener approach first. Here arc a few twists: • Use wood screws in acrylics and polycarbonates. Clamp the assembly together and drill a pilot hole, making it slightly smaller than the screw's outside diameter, and as deep as the screw is long. With a propane torch, heat the screw till it's deep blue. Push it into the pilot hole. The plastic will melt and conform to the screw's shape. When the screw is cool, remove it with a screwdriver, and replace it with a new screw.

• Cut threads in acrylic or polycarbonate with a tap. You then can turn a machine screw directly into the plastic, eliminating the need for a nut. Drill a pilot hole of a diameter halfway between the inside and outside diameters of the fastener's threads.

• Use self-tapping screws designed for use in metal. When turned into a pilot hole, a self-tapping screw will cut its own threads. (Repeatedly screwing and unscrewing this fastener destroys the threads, however, so use it only where assembly is a once-and-donc proposition.)

You can. of course, just use machine screws with nuts or bolts with nuts. Easy and familiar and practical and effective. Connect, for example, two pieces of plastic, a piece of plastic and a block of wood, or a plastic bit and a metal part. Use washers for best results.

When it comes to bonding plastic to plastic, wood, or metal, forget the familiar glues. They probably-won't be satisfactory. Instead, you need epoxies and special cements and solvents. Check the table below. To glue the plastic listed in the left column to various materials, use the bonding agent listed in the appropriate adjacent column.

Although you may never have

plastic...

to itself

to other plastic

to wood

to mcul

Acrylic cement

Acrylic cement

Acrylic cement

Contact cement

Polycarb cement

Synthetic rubber adhesive

Epoxy

Epoxy

Phcnolics

Epoxy

Epoxy

Synthetic rubber adhesive

To tap threads in a piece of plastic, you must first drill the hole to he tapped. Most laps are labeled with their size along with the size of the drill bit used to bore the pilot hole. Fit the tap in the tap wrench. Dip the tap in soapy water and, working clockwise, slowly twist it into the hole. Back it out of the hole periodically to clear it of plastic chips.

To tap threads in a piece of plastic, you must first drill the hole to he tapped. Most laps are labeled with their size along with the size of the drill bit used to bore the pilot hole. Fit the tap in the tap wrench. Dip the tap in soapy water and, working clockwise, slowly twist it into the hole. Back it out of the hole periodically to clear it of plastic chips.

used contact cement or epoxy, you certainly have heard of them, „ess familiar, perhaps, is synthetic rubber adhesive, which refers to the range of caulklike adhesives stocked by ever)' hardware store and building center. (Silicone-based adhesives work here, too.) Solvent and acrylic cement are probably new to you;

For routing along a straightedge, the fence-rider baseplate can't be heat. The baseplate design makes setup a snap and your cuts arrow-straight. The laminate-clad plywood we used is slick-sliding, too.

FENCE-RIDER BASEPLATE FOR FLAWLESS, FENCE-GUIDED ROUTING

Fence-Rider Baseplate

Simple to make, this baseplate has a long, straight edge that rides any fence you clamp to your workpicce, hence its name. The fence-rider has three benefits.

For routing along a straightedge, the fence-rider baseplate can't be heat. The baseplate design makes setup a snap and your cuts arrow-straight. The laminate-clad plywood we used is slick-sliding, too.

FENCE-RIDER BASEPLATE FOR FLAWLESS, FENCE-GUIDED ROUTING

First—and most obvious—it provides a long bearing surface to ride along any fence you clamp to a work-piece; you won't get a gouge or snipe at the beginning or end of a cut, where the round factor)' baseplate might lose contact with a short fence. Your cuts will be straight, too: The baseplate won't telegraph every dip and dent in your fcncc.

Second, it's dimensioned so the measurement from the bearing edge to the center of the collet is an easy-to-remember 4 inches. (Not something like 2Vit inchcs, the measurement on one router I've used.)

Third, the cuts you make will be consistently placed from the bearing edge. On many "stock" routers, the baseplate isn't concentric to the collet. II you twist the router a little as you slide it along the fence, the position of the cut swerves, giving you an uneven cut. Hie fence-rider's long bearing edge eliminates this maddening router foible.

The baseplate is an elementar)' project. Copy the layout from the drawing, duplicating it on your choice of materials. Cut it out. Using the factor)- baseplate as a template, mark the locations of the mounting-screw holes. Drill and countersink the holes, then attach the baseplate to the router. Cut a !A-inch-diamcter bit hole by switching on the router and advancing the depth of cut to plunge the bit through the baseplate. Measure 4 inches from the center of this hole to the fence-riding edge of the baseplate. Mink it. Remove the baseplate from the router and trim the edge. Finally, enlarge the bit hole.

The baseplate shown we made from i'Vinch plywood. It's covered on both sides with plastic laminate, which makes it smooth-sliding. The laminate, incidentally, reinforces the plywood enough to permit the use of the "stock" panhead mounting screws, sunk in counterbores.

both are sold by the same retailer who sells the plastic.

Of the latter two bonding agents, solvent sounds easier to use, but for router jigs-and-fixtures work, the acrylic cement may work better.

The solvents used effectively weld the plastics together. The parts to be joined are assembled, then the solvent—usually methylene dichlor-idc—is applied along the seams with

Solvent is a good way to bond two pieces of acrylic. The joint should be tightly jilted. Clamp the two parts together, as shown, and apply the solvent along the seam. Solvent is packaged in a plastic squeeze bottle with a handy syringe-type applicator top that makes this easy to do.

An offset baseplate is easily made and eminently useful for edge-routing. Hold down on the offset knob to keep the router from tipping, and push or pull the router along the edge with one of its knobs.

ITS BALANCE.

V4'-Z0 THREADED INSERT

MOUNTING HOLES

WCtLtf

POLYCARBONATE

SlZt BIT THROAT TO AÍCOMMOOATE LARGEST BIT YOU'LL USE.

An offset baseplate is easily made and eminently useful for edge-routing. Hold down on the offset knob to keep the router from tipping, and push or pull the router along the edge with one of its knobs.

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Wood Working 101

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