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Shaping Safety
Shaper Cutters
Cutter Storage
Fence Shaping
Pin Shaping

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Pin Shaping

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Figure 9-27. Collars control the depth of cut. Always be sure there is enough bearing surface between the workpiece and the collars.

Workpieces that are circular or have curved edges are done by pin shaping. This is a special procedure made possible by mounting collars on the arbor and using the shaper insert equipped with pins.

The collars, the pins and the table provide the bearing surfaces for the workpiece. The cutter may be over the workpiece or under it. You can use more than one collar of the same diameter to guide against thick stock. Warning: The important factor is the contact area between the workplece and collars (Figure 9-27). A small amount of contact area (less than half the collar thickness) is not adequate; always organize for maximum collar contact so the work will have good support.

Since the collars turn with the cutters, they can score or burn the Work unless they are kept smooth and free of gum, dirt, or dust. When you bear against them, use only as much pressure as you need to maintain the contact.

The cutters will function whether they are over or under the work-piece. The cut is easier to see and, some operators feel, is easier to control when the cutter is on top. Warning: If the workpiece is tilted up at any time during the pass, the cutter will dig into it. Positioning the cutter under the workpiece is the safest way to operate. Also, slight accidental lifting of the work during the pass will do no harm.

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Figure 9-28. The workpiece is first braced against the left pin and slowly advanced to contact the cutter.

Basic Procedure
The major factor to consider when pin shaping is the initial contact of the workpiece with the cutter. Warning: The workpiece, if moved directly into the cutter without support, will be kicked back. This is where the pins come into play. Start the pass by bracing the workpiece against the pin at the left of the cutter. With the workpiece firmly against the pin, slowly advance it to contact the cutter until it is solidly against the collars. Once the cut is well started, you can swing free of the left-hand pin and allow the workpiece to bear only against the collars (Figure 9-28). Toward the end of the cut, you can allow the workpiece to be supported by the right-hand pin.

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Figure 9-29. The pass can be made with the workpiece against the collar. Move the workpiece slowly in a clockwise direction.

Circles and Irregular Curves
Start shaping the edge of a circular workpiece by bracing it solidly against the left starter pin and then advancing it slowly to engage the cutter. After the workpiece bears firmly against the collar, you can choose to maintain the pin contact as you turn the workpiece clockwise (Figure 9-29) or swing it clear so only the work-to-collar contact is maintained. You can continue in this manner to complete the pass or, at the end of the cut, allow the right-hand pin to support the workpiece.

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Figure 9-30. The left-hnad pin comes into play when shaping irregular edges. Be very careful when shaping small radii and sharp corners.

Irregularly curved edges, such as those on fancy picture frames, wall plaques, free-form tabletops, and so on, are shaped much like circular pieces except that you should judge when to accept support from the left-hand pin and when to allow the workpiece to bear only agianst the collar (Figure 9-30). Always start by bracing the workpiece against the pin. Work slowly and carefully, especially when you must turn a sharp corner. Warning: Keep your hands on the outside edges of the workpiece so they will be away from the danger zone.

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Figure 9-31. You can shape slim, curved moldings by working on the edge of stock large enough to be safely handled.

Slim, Curved Moldings
To safely work on slim, curved moldings, you must follow the principle that was described for slim moldings: shape the edge of a workpiece that is large enough to be safely handled (Figure 9-31). Obey the rules that apply to pin and collar support for the workpiece. After the shaping is finished, use a scroll saw or bandsaw to remove as much of the edge as you need (Figure 9-32).

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Figure 9-32. Use a scroll saw or bandsaw to cut off the part you need after the curved edge has been shaped.


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Figure 9-33. Cut out and contour all inside edges first. The workpiece is fed in a counterclockwise direction. Be especially careful with hand placement. After completing the inside contour, cut the outside contour and shape it.

Inside Edge Shaping
Shaping a rabbet on the inside perimeter of a circular picture frame to accommodate the glass is a typical example of inside edge shaping (Figure 9-33). The workpiece is placed in position before the cutter is extended for depth of cut. The workpiece is braced against the right-hand pin and then swung into contact with the cutter until it bears solidly against the collar. It is then rotated counter-clockwise so the pass is made against the direction of rotation of the cutter (Figure 9-34).

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Figure 9-34. You can shape inside edges as shown.

This kind of work doesn't have to be limited to forming rabbets for glass in circular frames. By working the same way, you can add decorative internal edges on circular workpieces.

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Figure 9-35. Here are examples of special fistures you can make when you have many similar workpieces to produce. Fixtures mus be designed to suit the work you are doing. The position of the fixture determines how far the cutter penetrates the workpiece. The fixture control area mus match the curve in the workpiece. Be sure the contact areas are sanded smooth.

Special Techniques
For production runs on specially shaped pieces, it is good practice to create setups that provide accuracy while allowing you to work safely. The ideas that are shown in Figure 9-35 are diagrammed just to demonstrate how fixtures can be used.

The fixtures may be cut to shape on a scroll saw or bandsaw, sanded, and then clamped to the worktable to serve as guides when feeding the work. Quite often it is possible to use the scrap material from a cut piece as the guide. For example, the scrap piece from a circular cutout might make a good guide for shaping the edge of a circular workpiece. This idea, of course, calls for very careful initial cutting.

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