Drilling holes is an essential part of woodworking. In the first half of our article on drilling holes we looked at some of the common drill bits found in a workshop. We wrap up with input on the final bits as well as a tip on keeping them in good shape.
Drill and Countersink
While some modern screws are designed to drill their own holes as they are driven, most will benefit from drilling a pilot hole first. For speed and efficiency, nothing beats a combination drill bit and countersink.
In one easy operation they will provide a tapered hole in the second piece of wood for the point of the screw to grab onto; a clearance hole in the first for the shank of the screw, and a recessed countersink for the head.
These can be one piece, or made up of a counter- sink mounted to a standard drill bit.
Driving a screw into two pieces of wood without a clearance hole in the first piece will result in bridging; this is when the threads in the screw push the first piece away from the second piece before the screw grabs, leaving a gap that can’t be closed.
To provide a clean, finished appearance after countersinking screws, you can glue a small plug of wood into the hole and then pare it flush with the surface. These plugs can be quickly and easily cut in the shop using a plug cutter (mounted in a drill press) and some scrap from the project.
Plug cutters come in two main styles: tapered and non-tapered. The tapered plug cutter will cut plugs that are cone-shaped with one end being slightly narrower than the other. The advantage is that they can be inserted into the hole until they fit tightly on all sides.
A good set of twist drills, brad points, and Forstner bits will see you through most of the drilling applications you are likely to encounter in the shop, while a set of tapered drills with countersinks and a tapered plug cutter will see you through most of your hardware and fastening needs.
Is there a doctor in the shop?
Like all other edge tools, drill bits will perform best when they are kept sharp. Sharpening drill bits properly can be a bit tricky—the lip must be sharp and the clearance angle must be ground correctly for the bit to cut properly.
The Drill Doctor is a self-contained sharpening tool for twist drills that produces perfect results in minutes— every time. The dull bit is mounted in the chuck, which is then inserted into the machine. A diamond wheel powered by a motor provides the grinding action and all the operator has to do is rotate the chuck on the machine a few times.
In less than a minute, that old useless drill bit is as sharp as the day it was bought. The machine automatically grinds the proper cutting edge on the lip as well as the correct clearance angle behind the lip.
Part 1 of this column on drilling holes ran in the Tuesday, Oct. 13 edition of the Alberni Valley News-Advertiser and can also be viewed online by following our e-edition link at albernivalleynews.com.
Michael Kampen is the resident woodworker and manages the CNC Shop at Westcoast Home Hardware.