Pneumatic Fastening Tools and Air Compressors

Air Compressors

The driving force behind pneumatic tools, the air compressor is one piece of equipment, every construction worker should know how to maintain and put to good use. If you intend to go into certain trades or sub-trades, then you will eventually learn a lot more, but for now, the purpose of this unit is to introduce you to the safe operation of pneumatic tools and air compressors. To give an insight to how the tool works and what’s required to keep it in safe and operable condition. So don’t let the tangled looking mess on the previous page scare you, learn what the tool can do, and how to look after it whether it’s yours or not.

The compressor has become very popular because of the savings in time that comes with using air driven (pneumatic) fastening tools. The fasteners driven by these machines do not damage the wood fibers as much as nails do when they enter, and they do not leave the usual hammer dents in the surface. They are versatile machines, and relatively safe and easy to operate as long as certain precautions are taken.

Advantages:

The advantage in using pneumatic fastening tools (as opposed to the manual methods) far outweigh the disadvantages. The advantages can be summed up as follows:

1. Increased output reduces labor cost
2. One-hand operation allows fastening in otherwise hard to reach locations.
3. Finishing nails are automatically “set”.
4. Splitting of wood, particularly at the ends is practically eliminated

When there is no electrical supply to the work site, a gasoline motor driven compressor may be used. Remember that gasoline driven compressors cannot be used indoors because of the poisonous exhaust that is emitted.

Air Compressors and Lines

A source of compressed air is necessary for all pneumatic tools. However, not just any compressor can be used with a pneumatic fastening tool. The capacity must be matched with the demand for air. The demand for air will also be affected by the operating frequency of the tool.

The pump is the heart of the compressor. As the motor turns the pump by way of a Vbelt and flywheel, it causes the piston to compress the air in the cylinder and push it through a one way check valve into the tank. The safety release valve prevents excessive air pressure within the tank by operating at a pre-set pressure

Storage tanks vary from ¾ to over 250 gallon sizes depending on size and demands of the compressor. All tanks must have a drain cock to drain off air and moisture. This should be done at the end of every day. Air pressure is regulated to the tool by the regulator valve.

Maintenance

1. The oil level in oil lubricated compressors should be checked and changed periodically.
2. The air tank should be drained at the end of each day of use to remove moisture from the tank. Moisture will cause the tank to rust on the inside and create the potential for the tanks to rupture.
3. Check all hoses and fittings frequently for signs of damage or wear.
4. Never operate a compressor with the drive belt cover off.

Pneumatic Fastening Tools

Parts of a Fastening Tool
A. Exhaust Port
B. Piston
C. Driver Blade
D. Work-Contacting Safety
E. Trigger
F. Magazine

The basic parts of a fastening tool is shown . In this case it is an air nailer, but there is relatively little difference with other fastening tools. An air stapler is shown below.

How Fastening Tools Work

Clean, dry pressurized air is needed to power these machines. An in-line air pressure regulator, separator and filter should be used. The air pressure that is recommended for use with the machine should be clearly marked on the body housing. Do not exceed this by setting the regulator at the recommended pressure required.

Compressed air drives a piston attached to the driver blade which punches the fastener into the work.
To prevent accidental firing of a fastener, the triggering mechanism on all fastening tools is a two-step triggering process. In addition to the trigger there is also a work-contacting safety mechanism. This is a lever at the nose of the tool that must be depressed against the work at the same time that the trigger is pulled in order to drive the fastener. Neither the trigger nor the safety mechanism can release the fastener by itself. To prevent the gun from discharging accidentally, most are equipped with a trigger-interruptive safety devise. This prevents the trigger from being squeezed without another action first taking place. Some have a secondary trigger devise, but a tip safety lever is more common. These mechanisms allow the trigger to be depressed only when the firing tip of the gun is pressed downward onto the material.

Types of Pneumatic Fastening Tools

Fastening tools can be classified by the type of fastener that they use. In many cases fastening tools can only fire their specific brand of fasteners. The operating pressure requirements of the following tools is given in “psi” which signifies the required air pressure in “pounds per square inch”. The type of pneumatic tool will determine what the air pressure should be set at.

When choosing an air-powered fastening tool, it is always best to pay extra for a good one. It is not uncommon for a cheap machine to have working parts of poorly machined and/or soft material, yielding a short working lifespan. A top-quality, well-maintained version of the same tool will have a much longer lifespan, and is obviously much more economical. Look for a machine with good castings and precision machining on all moving parts. Research brand names and models, keeping your needs in mind, as there are many different sized machines for many different applications.

From my point of view, I’ve always found the air nailer that accepted the coil collated nails, to be easy to work with in tight spaces, simply because they are shorter and a little more compact.

No tools can fire all the different nails available. Within each group of nailers there is also a variety of tools sizes.

Finishing Nailers

Brad Nailer
Applications: Baseboards, casings, cabinetry, etc…

Heavy Duty Nailer
Applications: Construction framing, wood-to-concrete, truss building, sub-flooring, side wall sheathing, pallet making,etc…

Staplers Heavy
Duty Stapler
Application: Crating and pallet making, framing, sub-flooring, sheathing, etc.

Types of Fasteners

There are may different fasteners. They vary in size; shape; the material from which they are fabricated; the type of coating applied to them; and how they are collated (straight or angular clips or coiled).

Air-powered fastening tools use long, thin, steel nails or staples, which are driven into the material with air pressure of about 100 psi. The driving action is instantaneous, and the fastener has been driven before the brain can comprehend.

Staples and nails for air fasteners are thin, flexible and sharp, and will bend easily if they encounter an obstruction as they are being driven. They may make turns within the material, and exit on unexpected places. Pay attention, and do not place your hands near the area being fastened.

Machines made by different manufacturers require different sizes and configurations of fastening devices. When purchasing a machine, make sure that the fasteners for it are readily available and will remain in production. Different fasteners are made for different materials and holding applications, and are available in strips or rolls, which load into a magazine on the tool.

Disconnect the air supply before making adjustments. To facilitate this, the air hose should have a quick-connecting coupling to the tool. When re-connecting the air supply, point the tool away from yourself and others. To reload the air tool with fasteners, you need not shut disconnect the tool, but you must keep your finger off the trigger!

Nails

Nails used in pneumatic fasteners are a lighter-gauge than their hammer driven counterparts. Nails are available in regular steel, galvanized, or aluminum. Aluminum nails are ideal for situations where there is a possibility of corrosion.

Staples

Staples spread out their holding force over a larger area than nails giving them a greater holding force. However, staples should not be used on surfaces that must be finished because they are difficult to conceal. The types shown are available in strips similar to the other straight collated fasteners.

Brads

Brads and Finishing nails are also available in strips in most brands of pneumatic tools. They speed up finishing jobs because they are driven much faster, and are instantly countersunk.

Operating Procedures

All pneumatic fastening tools are potentially dangerous if they are not used with great care and common sense.

All pneumatic fastening tools must be properly supplied with compressed air only. Set the line pressure with the regulator valve to the correct operating pressure for the tool being used. This air should be clean and dry and not replaced with any other compressed gases such as CO2, or O2

There are a number of different sized “quick couplers” available for attaching tools to air lines.

When connecting the air supply hose to the tool, a fastener can be accidentally discharged. So care must be taken to always point the tool down and away from yourself and anyone else.

Each time the tool is fired a blast of air is exhausted. Make sure this air is not directed at yourself.

If the recommended operating air pressure is not known, start with low pressure and gradually increase until proper functioning is achieved.

Maintenance

To ensure safety and long life of pneumatic fastening tools, a few precautions should be taken with the air supply. The most common causes of malfunction are:
Incorrect air pressure (too much or too little), and
Dirt and moisture getting into the tool from the air supply.

Safety and Procedures

Compressed air can be dangerous even to the point of death. A blast of air at 40 lbs. per square inch (275 kN/m) can rupture an ear drum or bowel, and can cause damage to skin tissue resembling a burn.

The tremendous force that is harnessed within an innocent looking pipe or hose is too often taken for granted. This useful power source can be made safer by following a few safety precautions:

1. Secure all connections properly, but do not strip or cross the threads.
2. Do not run over air hoses with equipment, keep them clear of walkways by suspending overhead whenever possible.This also will prevent kinking, possible cuts, or the hose becoming a tripping hazard.
3. Do not crimp hoses to cut off air.
4. Always wearing safety glasses is the most important safety requirement a worker should observe when operating an air tool.
5. Never direct compressed air towards yourself, another person or animal.
6. The loud percussive sound of cylinder during the driving stroke will necessitate hearing protection as well.
7. Never use compressed air to clean up floors or clothing.
8. Press the nose of the tool onto the material and push downward to clamp the piece, and to depress the safety mechanism.
9. Aim the nose of the tool in the direction that you want the fastener to go, and pull the trigger. The fastener is driven.