Tip #52
Shopsmith Jig Saw (continued)
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General Scrollwork

Figure 16-8. As you cut with the jigsaw, feed the work slowly. Do not force it or try to turn a corner that's too tight for the blade.

As you get ready to cut, adjust the height of the hold-down for the thickness of the workpiece. Give the drive shaft a few turns with your hand to make sure the blade is operating freely. Make a five-point check: all locks-power plant, carriage, table height, table tilt and quill-should be secured. Check that there is 30W light machine oil in the reservoir.

Take a comfortable stance in front of the blade, with the teeth pointing toward you. Your position is determined by whatever gives you the most control over the workpiece you're about to cut. For some patterns, you may find it necessary to shift positions as you cut, from directly in front of the blade to one side of it.

Turn on the jigsaw, set the speed dial, and let the jigsaw come up to speed. Then slowly feed the work-piece into the blade. Use both hands to guide the workpiece, and keep it pressed firmly down against the table (Figure 16-8).

Feed the workpiece forward using very light pressure. Do not force the workpiece. Force feeding will not speed up the operation; instead, the blade twists and runs off course. If you press too hard, the blade will break.

Using side pressure (against the flat of the blade) or trying to turn a radius too small for the blade will also cause a blade to run oft course or break, giving you an inaccurate cut. Feed the workpiece directly against the teeth, even when cutting curves. To determine if a curve is too small for the blade, use this rule of thumb: the smallest circle you can accurately cut will have a radius twice the width of the blade you're using. If you're using a blade 1/4" wide, don't try to turn corners with a radius of less than 1/2".

Here are a few tips to help you get good results from jigsaw cutting:

Cutting Complex Patterns- Break complicated cuts up into simpler curves and lines. Don't hesitate to leave the pattern line, sawing into the waste stock; then loop around and attempt the next part of the cut from a better angle. Carefully plan your cuts before you begin.

Figure 16-9. Here are two methods for cutting an exterior corner. In the first method, cut line A; then loop around in the waste stock to cut line B. In the second, cut line A and continue past the corner to the edge of the work-piece. Turn the workpiece and cut in from the edge to line B.

Sometimes, you'll want to cut complex patterns, but there will be no waste stock in your design-this is often the case when cutting matching parts. In order to do this, modify the pattern so that it can be cut without departing from the line. Or, select a smaller blade that will cut all the curves and corners in one pass.

Cutting Sharp Corners-If your design calls for sharp corners where two lines intersect, there are several ways to cut these with the jigsaw.

To cut sharp exterior corners, cut the first line and keep on going past the corner. Loop around in the waste portion of the stock, and come back to cut the second line. Or, cut the first line and go past the corner to the edge of the work-piece. Remove a portion of the waste, turn the workpiece, and cut in from the edge to the second line (Figure 16-9).

Figure 16-10. Here are two methods for cutting interior corners. In the first method, cut line A, back completely out of the stock, and cut line B. In the second, cut line A up to the corner. Back up, turn into the waste stock, and cut line B-all but a small part near the corner. Remove the waste stock; then go back and cut that small portion of line B up to the corner.

To cut sharp interior corners, cut the first line up to the corner; then back the blade out of the stock and cut the second line. Or, cut the first line up to the corner and back up several blade widths. Turn into the waste stock, leaving the first line and getting in position to cut the second. Cut the second line (all but a small portion near the corner), remove the waste, then go back and cut the last part of the second line up to the corner (Figure 16-10).

Figure 16-11. When cutting thin or A small workpieces, tape them to a sheet of posterboard. This adds both support and control.

Cutting Thin or Small Stock-When cutting veneer or very thin materials, it's helpful to tape the workpiece to a sheet of heavy posterboard; then cut the work-piece and the posterboard. (Don't use corrugated cardboard.) The posterboard adds extra support and keeps parts of the workpiece from breaking off and falling through the hole in the table insert (Figure 16-11). If the pattern is very complex and/or the materials very fragile, you may have to sandwich the stock between two pieces of posterboard.

This technique also comes in handy when you need to cut stock that's too small to safely control. Simply attach it to a larger sheet of posterboard; then hold onto the posterboard and use it to guide the stock.

Figure 16-12. If you need to cut identical parts, stack up the workpieces and tape them together. Cut them all at once. This is called pad sawing.

Cutting Identical Pieces-If you need to cut several identical parts to a project, you can use a technique called pad sawing. Stack up the workpieces and tape them together. The stack should be no thicker than 1-3/4". Saw the entire stack at once; then remove the tape. Each piece will be identical (Figure 16-12).

If you're pad sawing a stack of veneer, put a sheet of posterboard on the bottom and the top of the stack to prevent small pieces from breaking off. Draw your pattern on the top sheet of posterboard.

Figure 16-13. Inlay work is done by making a "pad" of veneers. After cutting, each piece will fit the corresponding hole in another.

Inlay Work-Inlay design work or pictures are made by using the pad method of sawing shown in Figure 16-13.

The veneers selected are fastened together between top and bottom boards with nails driven through waste areas. The picture or design is on the top board. Since all the veneers are cut at the same time, any piece cut out of one will fit the corresponding hole in another. The veneers should be selected for contrasting colors and grains.

Inlays are also made by jigsawing a form from a piece of stock and gluing it into place in a recess carved or routed out for it. This is called intarsia and is shown in Figure 16-14.

Figure 16-15. A wide, coarse blade will do a fast job when cutting thick stock. One with fine teeth will cut more slowly but with a smoother finish.

Cutting Thick Stock-When you must cut thick stock, take your time. Use as wide a blade as possible, coarse teeth, and a slow speed (Figure 16-15). The jigsaw is not designed to cut through thick stock as quickly as a bandsaw or table saw. Remember, heavy forward pressure won't hasten the operation-it only makes the cut inaccurate and it may cause the blade to break.

Figure 16-16A. (A) A jigsaw fence that you can make is held to the table with a clamp.

Figure 16-16B. (B) Construction details for the jigsaw fence. Click on image for larger view.

Straight Cutting-The jigsaw or bandsaw, but if you have it set up and need to do some straight cutting, there's no need to change to another machine. Just accept that the cuts will take a bit longer to do. You can guide the work freehand, but it's more convenient and you'll work more accurately if you make the fence shown in Figure 16-16.

Figure 16-17. Using the fence to make a straight cut. Don't expect the jigsaw to cut as quickly as a table saw or bandsaw. The blade will wander if you try to rush.

When ripping, clamp the fence to the table so the distance from blade to fence will equal the cut width you need. Hold the work snugly against the fence and move it forward slowly to make the cut (Figure 16-17). A wide, coarse blade will make this type of cutting easier to do, but a medium-width blade with finer teeth will produce smoother cuts.

Figure 16-18. The fence can be used as a cutoff gauge. Be sure the triangular piece used as a miter gauge is square to the fence.

You can use the jigsaw fence to gauge cutoffs; thus, you can work as shown in Figure 16-18 to produce duplicate pieces. The "miter gauge" is a triangular piece of wood that has been carefully checked to be sure the edges that will bear against the fence and the work form a 90° angle.

Figure 16-19. Use the jigsaw fence for cutting dowels. Hold the dowel firmly or it will tend to rotate during the cut.

Use the same setup when you need to cut dowels (Figure 16-19). Adjust the spring hold-down just tight enough so the dowel won't bob up and down with the blade. Also, hold the dowel tightly so it won't turn as the cut is made.

Cutting Bevels-On many types of inlay work and on heavy stock, bevel cuts are used so that any internal piece will jam tight when pushed through the piece from which it has been cut. The bevel may range from 10 to 100 and is adjusted by setting the table to the angle desired (Figure 16-20).

Figure 16-20. You can cut bevels by tilting the table to the angle you need.

Cut precisely on the line, but keep the work always on the same side of the blade. It cannot be swung completely, since this would change the direction of the bevel; then the pieces wouldn't fit.

Figure 16-21. This is how bevel cut pieces fit together. Click on image for larger view.

Figure 16-21 shows how bevel-cut parts fit together. In (A) is shown a kerf that was cut with the table in a normal, horizontal position. In inlay work, this kerf (very slight when the proper blade is used) is sealed with a filler, which also provides a defining border around each of the pieces.

For a closed kerf line, the table is set for a bevel that produces the results shown in (B). When part 2 is jammed into part 1, the two pieces form a perfect closed joint.

Figure 16-22. (A) Bevel cutting, done on one piece of stock, can produce deep projects.

On heavier stock, bevel-cut pieces can be joined with the cutout piece raised above the surface of the piece from which it was cut (C). An application of this technique is shown in Figure 16-22. This is a good method of making raised bases, or hollow projects. The method may also be used to build up stock to be mounted and shaped on the lathe.

Figure 16-22. (B) Each piece fits into its neighbor.

Model-boat builders will find the technique of value in forming boat hulls.

Figure 16-23. The bevel cutting technique is often used by model builders to shape hollow boat hulls.

The layout of the pieces is made on the surface of the board, which is then bevel-cut in the manner explained.

When the pieces are extended, the boat hull takes the shape shown in Figure 16-23, ready for final finishing.

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