Tip #26
Drill Press (continued)
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General Drilling

There are two basic types of holes: holes that you drill completely through the workpiece and holes that you drill only partway through the workpiece.

Figure 7-9. When drilling, use the rip fence to accurately position the holes. Make fine adjustments with the table height leer (Model 500) as shown or with the table adjustment crank (Model 510).

Drilling Through
Mount the rip fence on the worktable. It will be used as a backstop. Adjust the rip fence to help you accurately position the hole where you want it. Make fine adjustments with the table height lever (Model 500) or crank (Model 510) (Figure 7-9). If there's no room for the rip fence, use the miter gauge. Caution: Place a scrap of wood, wider than the workpiece, on the table to keep the bit from drilling into the table after it goes through the workpiece. It will also help keep the workpiece from splintering where the bit exits.

Hold the carriage so that it won't drop against the base mount. Loosen the carriage lock and adjust the table height so that the tip of the bit is 1/4" to 1/2" above the workpiece. Then tighten the lock.

Figure 7-10. Use the depth control to keep the bit from biting through the scrap block and into the worktable.

Extend the quill so that the tip of the bit touches the scrap block. Set the depth control to approximately 1/8", and tighten the depth control lock (Figure 7-10). Then retract the quill. When you drill the hole, the depth control will keep the bit from biting through the scrap block and into the worktable.

Make a five-point check. Four of the five locks--power plant, carriage, table height, and table tilt--should be secure. The quill lock should be loose.

Figure 7-11. Before turning on the machine, extend the quill to be sure the bit will drill a hole where you want it.

Place the workpiece on the worktable and position it under the bit. Hold it firmly against the table and rip fence. Extend the quill with the machine turned off to be sure the bit will drill a hole right where you want it (Figure 7-11).

If the bit lines up correctly, turn the Mark V on and adjust it to the correct running speed. Feed the bit into the wood slowly and evenly (Figure 7-12). Don't force the bit; just maintain a light, steady pressure. When drilling deep holes, it is necessary to retract the bit now and then to clear chips from the hole.

Figure 7-12. Feed the bit into the wood slowly and evenly, maintaining a light, steady pressure. Stop when you feel the depth control halt the quill.

When you feel the depth control stop the quill, retract the bit. Turn off the machine, let it come toa stop; then remove the workpiece.

Avoiding Tear-out--Tear-out, the rough, splintery edges where the bit exits the workpiece, can be avoided by moving the scrap block every time you drill a new hole, so there's always a flat, firm surface to back up the workpiece. Or, if you're using brad-point bits, you can use the depth control to avoid tear-out.

With the Mark V turned off, extend the quill until the pilot of the bit touches the scrap board. Set the depth control to "0" and lock it in place. Let the quill retract.

Figure 7-13. When a bit exits a hole, you may get smoe tear-out, as shown on the right. To avoid this, grill partially through the board until just the pilot of the bit comes out the other side, as shown in the center. Then turn the workpiece over and drill from the other side. The hole will be clean, as shown on the left.

Drill the holes you need, letting the depth control stop the quill. Turn off the Mark V and turn the workpiece over. There will be tiny pinholes where the pilot started to come through the workpiece (Figure 7-13). Use these pinholes to line up the bit; then finish drilling the hole from the other side. Since brad-point bits have spurs that cut the wood grain smoothly when they enter the wood, there will be no tear-out on either side of the workpiece.

Figure 7-14. Extend the quill until the cutting flutes of the bit just touch the workpiece.

Drilling Partway
To drill a hole only partway through a workpiece, extend the quill until the cutting flutes of the bit just touch the workpiece (Figure 7-14). Set the depth control at the desired depth and lock it in place; then drill the holes you need.

The depth control will stop the quill when the bit reaches the proper depth in the stock. All the holes you drill at any one depth control setting will be exactly the same depth.

Figure 7-15. Extend and lock the quill so the point of the bit liens up with the mark you've made on the work.

Another way of drilling partway is to mark the work to indicate the necessary hole depth. Extend and lock the quill so the point of the bit lines up with the mark on the work (Figure 7-15). With the quill held in the extended position, rotate and lock the depth control at "0" (Figgure 7-16). Unlock the quill and proceed with the drilling.

Figure 7-16. Then turn and lock the depth control at "0". The quill will extend only the distance you have determined.

Drilling Screw Holes

Figure 7-17. A screw usually requires a shank hole for the shank and a pilot hole for the thread. The shank hole should equal the gauge of the screw and go through the first piece. The pilot hole should be half the length of the threaded portion of the screw.

If screws are to drive easily and hold with maximum strength, the screw holes must be drilled carefully and to size (Table 7-2). Usually two holes are needed: the shank hole, which equals the screw diameter, and a smaller pilot hole, which allows the screw end to penetrate the wood (Figure 7-17).

The easiest procedure is to drill the shank hole first. This establishes a guide and a center for the pilot hole. Countersinking, which can be controlled by using the depth control, is done on the surface to establish a seat for the head of the screw when it must be flush with the surface of the work (Figure 7-18). In softwoods or when the head of the screw is small enough, countersinking may be eliminated since the screwhead will form its own seat as it is turned into the wood.

Figure 7-18. A special tool called a coutnersink forms the inverted cone that allows coutnersunk screws to seat flush with work surfaces. Use the depth control to obtain identical countersinks.

Screw and bolt holes can be counterbored when it is desirable for the fastener head to be set beneath the surface of the wood.

Counterbored holes are often sealed with plugs cut from the same type of wood. These may be set flush with the surface of the work and glued in place so the grains match, or they can protrude slightly to provide a decorative touch. This is seen quite often on Early American furniture.

Figure 7-19. Screw bits control hole depth and countersink diameter.

Special bits, like the screw bit shown in Figure 7-19, let you drill accurate screw holes with minimum fuss. They are actually bits that form tapered holes and have sleeve-type, adjustable counter-sinks and collars so you can control hole depth and countersink diameter.

Drilling Holes Through Extra-Thick Stock
Because a spindle extension has a limit and bits should not be buried in the work more than the length of the bit's flutes, it isn't possible to drill through extra-thick stock in normal fashion. You must drill from both sides of the stock. The problem is that it is difficult to drill both holes on the same centerline; the solution is to use a guide that correctly positions the work after the first hole is drilled.

Figure 7-20. This is one way to drill from both ends of extra-thick stock. The work, positioned over the guide pin, is accurately placed for the second hole.

One method is shown in Figure 7-20. After the first hole is drilled in the work, clamp a piece of scrap to the table and drill through it. Insert a hole-sized piece of dowel in the scrap piece, replace the work so the first hole drilled will be over the dowel, and finish drilling.

Another method calls for a special insert (Figure 7-21A), one you can retain for future, similar operations. The drilling procedure is the same. Drill the hole as deeply as you can, or a little more than halfway through the stock. Then position the work by placing it over the pin in the insert and finish drilling (Figure 7-21B).

Figure 7-21. Another way to drill extra-thick stock is to: (A) make a special insert with a correctly located guide pin. (B) Then after the first hole is drilled, the work is inverted over the guide pin so it is accurately aligned.

Figure 7-22. Construction details of a special drilling insert. Use your table saw insert (Model 500 or 510) as a pattern. Drill a hole for the dowel after the special insert is secured in the table.

Make the special insert like the one detailed in Figure 7-22. Drill the hole for the guide dowel after the insert is assembled and locked in the table. Thus, alignment of the bit to the guide dowel will be assured.

Drilling Extra-Large Holes
Large diameter holes, can be formed using special cutters such as hole saws (Figure 7-23). Hole saws are heavy steel cups with small saw teeth on the perimeter. They mount on mandrels that have a shank that can be gripped by the drill press chuck. One mandrel is usable with several sizes of hole saws.

Figure 7-23. Place a backup under the workpiece, set the depth control, then feed the hole saw lightly at a speed that permits it to cut without burning or binding.

Start the operation at the proper speed recommended by the manufacturer and slowly increase feed pressure until the saw is cutting smoothly and without binding or burning.

Figure 7-24. Plug cutters are precision tools that will form wood cylinders of exact diameter.

Plug Cutting
As mentioned earlier in the chapter, the best method to conceal screwheads so they don't spoil the appearance of a project is to counterbore for them and then fill the hole with a wooden plug. Often, the hole is filled with a short length of dowel or a commercial, preformed plug. Both ideas work; however, the items are available only in limited wood species and it's often impossible to match the grain pattern of the plug and the work. The solution is to make your own plugs by working with plug cutters like those shown in Figure 7-24. With these, you can cut into the edge or end of stock and not only use a matching wood, but also control the grain pattern. Plug cutters are available in the sizes shown in Table 7-3.

Figure 7-25. Wood plugs are commonly used to conceal screwheads. The basic procedure is shown here.

A basic procedure is shown in Figure 7-25. Drill through the stock and remove the plug. Cut the plug about 1/16" longer than needed with a bandsaw, scroll saw or hand saw. Coat the plug with a little glue, match the grain, and then drive it into the counterbored hole. After the glue is dry, you can sand the plug flush or allow a bit of itto project as a decorative detail.

Figure 7-26. Another type of plug cutter will cut 2" deep. It can be used for shor plugs and for dowel-type cylinders.

Another type of plug cutter, shown being used in Figure 7-26, can be used like the first ones mentioned but can cut deep enough to form plugs, or short dowels, up to 2" long. Thus you can use them to form custom dowels for edge-to-edge joints and even to shape axles for small toy projects. Work as shown in Figure 7-27 when you want the wood grain to run in the plug's long dimension. After the plugs are formed, they can be separated by making a cut on the bandsaw or table saw.

Figure 7-27. Using the extra-deep plug cutters this way lets you form dowels for edge-to-edge and other type joints. A saw cut separates the dowels from the base stock.

Figure 7-28. You can relocated a hole or enlarge one already drilled if you first seal it with a plug so you can center the bit for the new hole.

An interesting use for plugs is shown in Figure 7-28. If you have made a mistake locating a hole or simply wish to enlarge a hole, fill it with a plug so you can establish a center for the new hole.

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