Basic Woodworking

WOODWORKING

Chapter 18

Metal Fasteners

Introduction:

A metal fastener is a hardware device, such as a nail or screw, which

mechanically joins or affixes two or more objects together. The most common

metal fasteners used in woodworking joinery are:

1. Nails (hammer and pneumatic)


2. Wood Screws (open, plugged, capped, putty)


3. Bolts


4. Pocket screws

Nails:

There are two common types of nails you will use in woodworking,

common nails and finishing nails. Common nails, used primarily in

construction, have a flat head. Finishing nails, however, have a head only

slightly larger than the nail shank itself and is designed for “punching” or

sinking into the wood with a device called a hole punch. By doing so, the nail is pressed into the wood and

recessed in such a way as to make it ready for the application of putty. This “filler” hides the nail from view and

helps to maintain the natural beauty of the wood.

Nails may be inserted into lumber either manually, with the use of a hammer, or pneumatically, with the use

of an air gun.

Wood Screws:

Unlike the smooth shanks of many nails, screw fasteners

have a threaded shank with machined spirals shaped in such a

way that the screw may be inserted or removed by rotating the

head. There are two common thread types, coarse thread and

fine thread. Coarse threaded spirals are further apart and deeper

than fine threaded spirals and should be used in softwoods.

Because hardwood grain is more compressed, fine threads

should be used.

When using a screw fastener, you must decide how you will

finish the head of the screw. You may mount the screw with its

head above the surface of the wood (surface mount), flush with

the surface (flush mount), or below the surface (hidden mount).

Both surface mounted or flush mounted screw heads are visible, while hidden screw heads are not. For all

methods of mounting screws, a pilot hole should be employed before penetrating the lumber with the fastener.

A pilot hole is a hole slightly smaller than the screw shank itself and is drilled through the wood where the

screw will be mounted. This pilot hole prevents the wood from splitting or splintering when inserting the screw.

Flush mounted or hidden screw heads require a counter sink hole. Counter sinking is the method of drilling a

hole into the pilot hole wide enough for the head of the screw to go into. When the screw is attached, the wider

hole allows the head to penetrate flush or below the surface of the wood. The deeper the counter sink hole, the

further in the screw will penetrate. To completely hide the head of a screw, putty, wooden caps, or plugs may

be inserted into the counter sink hole.

Bolts:

Bolts are not pointed like screws or nails and are not driven into wood.

Rather, holes the size of the bolt must first be drilled through both pieces of

wood to be adjoined. Bolts have flat heads and are designed to use a nut or a

threaded insert. The nut, often used with a washer, is attached to the end of the

bolt and tightened with a wrench to squeeze the two pieces of wood together.

Inserts are recessed into the wood and creates a threaded hole for the bolt.

Carriage bolts have smooth heads and may only be tightened with a nut.

Standard bolts have a hex head for applying a wrench.

Joinery