Consider Multiple Factors when Selecting a Hand-Portable Air Compressor

By Dan Leisse — Sep 04, 2012

Selecting an air compressor at first seems so simple. How tough could it be? All you have to figure out is how much air you need and decide how much you want to spend. Right? Actually, there are multiple factors that must be considered to find the right compressor for the job. From air pressure to horsepower, a contractor must identify the proper balance of features to meet his or her needs. Let’s break out some of the key factors to help make the decision process a little easier.

Portability, Flexibility Needs

When looking at hand-carry or wheeled air compressors, portability will be a given. The bigger concern will be ensuring the model also meets the pressure and capacity requirements of the job. With their low weight and compact configuration, these air compressors can go pretty much anywhere — with one condition — which is what we need to look at next.

Power Source

The next obvious step involves considering where the compressor will be used. If working in a remote area without access to electrical power, either from the grid or from a generator onsite, the only choice is a gasoline engine model. That will offer mobility around any jobsite. But there may be other issues that come into play, such as environmental restrictions — emissions in a confined space or noise abatement — that cancel out the advantage of convenience. The gasoline model also will have both a higher purchase price and the ongoing costs will be greater, but it will provide higher actual horsepower than its electric-motor counterpart. 

CFM Required

Besides power, capacity will directly impact what the compressor can do. Begin by adding the CFM (cubic feet per minute) requirements for all the tools that will be used simultaneously, and then add another 30 percent to allow for unknown or uncommon compressor usage. The CFM rating can be found either on the tool itself or in the owner’s manual. It can be figured three ways:

1. Displaced CFM (DCFM) is simply a mathematical calculation of the bore, stroke and rpm. But, it does not take into account any of the important variables, like temperature, atmospheric pressure, humidity, friction or heat dissipation, and therefore it means almost nothing in the real world.

2. Standard CFM (SCFM) is a better measure of reality. SCFM is the flow of free air in a standardized environment — such as 14.5 psi atmospheric pressure (the pressure at sea level), 68 degrees Fahrenheit and 0 percent humidity.

But what about individual needs? For example, if someone is working in mile-high Denver in January, it surely isn’t going to be 68 degrees. Or, a person could be in Louisiana in July, and the humidity is off the charts.

3. Actual CFM (ACFM) figures in the variables that apply to unique situations. It will provide output of the pump for the actual working conditions. But ACFM is a hard figure to get, precisely because it does require site-specific data and calculations that may be best left to an engineer.

For selection purposes, the best bet is to compare compressors based on the SCFM ratings. This puts all units on a level playing field for a true apples-to-apples comparison.

Required Operating Pressure

CFM will also be important to know when considering a single-stage compressor vs. a two-stage model. Begin by listing the minimum operating pressure requirements for the tools that will be used, which will indicate whether a single- or two-stage compressor is needed. Single-stage compressors are fine up to 150 psi. Anything more will require a two-stage. A single-stage compressor will typically have a higher CFM rating, because the cylinder is drawing in air and compressing it with every rotation, whereas a two-stage is compressing the air up to an intermediate pressure in one or more cylinders and then passing it on to another cylinder to finish the job. Because the air is typically passed through an intercooler between stages, a two-stage compressor is more efficient at higher pressures.

Receiver Tank

Once again, the capacity of the compressor tank, which is usually measured in gallons, depends on how the compressor will be used. If running tools that require quick, concentrated bursts, such as nail guns, a small tank is best. If the tools are to be used for sustained periods, such as impact wrenches, a larger tank will work better.

Overall, the most critical issue to keep in mind is job analysis. To select the right compressor for your operation, it’s best to understand the requirements of your current and future projects. Start by creating a realistic checklist using the factors outlined above. From there, it will be much easier to find a unit that will meet your needs and keep your business powered for years to come.

Dan Leiss is president of Jenny Products Inc., based in Somerset, Pa.  

Before Compressor Operation Begins

Make sure the air compressor is clean from previous work. It will be easier to detect leaks and broken or loose components on a clean machine. Before turning on the machine, do a visual inspection. Check the hoses for kinks and the electrical wiring, tubing and piping for any damage. Also check the controls, gauges, accessories and instruments to make sure there are no loose mountings or visible damage. Check all connections and tighten any loose nuts and bolts.

The next step is to check the pump oil level. To do so, first disconnect the power source and place the compressor on a flat surface. Remove the oil fill plug and check the level, then insert a screwdriver into the crankcase. Inspect the oil on the screwdriver. If there are signs of contaminants, such as water or dirt, change the oil. Otherwise, change the oil annually. If a gas engine powers the compressor, check the engine oil level, as well, which also should be changed annually. Fuel filters may be changed to accommodate an air compressor’s daily task. There are two types of filters: standard and coalescing. A standard filter will trap dust particles based upon micron size, while a coalescing filter will remove water and oil from the air. Provided the correct filter is used for each application, it should only need to be replaced monthly or every few months.

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Maintenance Tips for Keeping Your Compact Track Loader Running Reliably
Compiled by CE Staff — June 21, 2012

A compact track loader is one of the most versatile and useful tools within a contractor’s equipment fleet, providing improved capability over soft terrain and increased capacity compared to skid steer loaders. However, the very items that make them unique and so useful also require some special care to ensure reliable service and uptime.

Maintaining the operators area is not that much different than on other pieces of equipment except that when track loaders are operated on hard surfaces, vibration of the cab and components is more intense. New track loader designs have taken steps to provide a smoother ride. Over time, intense vibration can lead to more maintenance depending on specific applications and operating conditions (like operation in soft soils vs. operation with a cold planner on concrete). With this in mind, an operator should pay special attention to hardware to ensure that all components stay securely in place. Cab mounts, seals and hardware should be checked on a regular basis. Loose components and hardware should be tightened, and damaged components should be replaced.

Track loaders are generally operated in dirty or soft ground conditions. Operators entering the cab tend to bring in a lot of soil and mud on their boots. As with most other products, the operator’s area needs to be cleaned on a regular basis. If the floor pod does not tip forward for easy clean-out, a shop vacuum should be used to ensure debris is removed. This is particularly important if the unit is equipped with an enclosed cab and air conditioning or heat. If the cab is equipped with a re-circulating air filter and a cab fresh air filter, they should be serviced on a regular basis. Keeping the air conditioner clean will ensure its long-term reliability.
The operator’s manual supplied with the product provides critical safety information and instructions on normal engine and hydraulic system oil and filter change intervals. Track loaders operate in fairly difficult conditions; spending a few extra dollars for regular oil sample testing will maximize your change intervals and help to ensure you are changing your oil and filters adequately. Oil sampling will also provide short- and long-term indicators of unusual wear or failures that are in progress to help eliminate downtime during critical periods.

Since track loaders are uniquely qualified to operate in harsh soil conditions, it is also important to check the chassis. Be sure all covers, doors, belly pans and shields are in place, in good condition and securely fastened. Manufacturers recommend the chassis be kept clear of debris, and in most cases, cleaned daily. This is required to prevent catastrophic failures due to accumulation of foreign material or overheating due to plugged radiators. The heart and soul of a compact track loader is its undercarriage and track system. Proper operation and maintenance will either lead to greater productivity or downtime and high operating expense. Proper operation and maintenance is not difficult, but does require following recommendations in your operator’s manual.

Track tension is very important to extend the life of tracks and the rolling elements of the undercarriage. In fact, improper track maintenance may be the single largest contributor of premature wear and failure of tracks and components, especially if tracks are over-tightened to delay normal adjustments. Over-tightening the tracks also robs horsepower and increases the likelihood of damage to tracks during machine operation. Don’t forget to inspect the track on a regular basis.

Overall, track loaders offer many operating advantages over wheeled loaders depending on soil conditions and allowing improved productivity. In fact, track loaders remain productive when select soil conditions make wheeled machines useless. But as with any machine, they must be maintained properly. A little extra time spent on them each day before they are operated will increase their productivity and ensure they are operating when they should be.

Smart Tips for Simple Hand-Held Earth Auger Operations
Dennis Von Ruden — Sep 07, 2011

Jobsites don’t see too many machines simpler than an earth auger. However, manufacturers build them this way because there’s just no reason to make them complex. Even an auger’s purpose is simple. Whether the application is construction, landscaping, fence installation or a homeowner project, earth augers do one thing and one thing only — dig holes.

But while the equipment and its function are not complicated, not everyone will achieve the same level of success with a hole digger. There are some basic operational hints — along with a list of mistakes to avoid — that should be considered in order to ensure safety and maximize productivity on the job.
 

Ready to Dig?

There’s no sense in getting started until both the equipment and operator are prepared to go to work. Assuming the hole digger itself has been properly maintained and is in good mechanical condition, the first thing the operator should do is examine the auger’s common wear parts, such as the screw bit and teeth.
The screw bit is the very tip of the auger. If it is extremely worn — or perhaps even completely gone — the auger will not track straight as it digs. Augers can dig aggressively when their teeth are in good shape, but if not, the auger flighting must pick up the slack and absorb unnecessary wear. Worn teeth can also decrease digging capacity and force the auger to become stuck in the ground.

Next, take time to read over the operator’s manual. While this task may seem unnecessary to some experienced operators, it’s still an important step — particularly if it’s been a while since the operator has used a hole digger, or if the equipment works a little differently than augers he or she has used in the past. Manufacturers cover just about everything there is to know about safe and efficient operation in their manuals. This information is invaluable for novices, and giving the manual a quick read might even teach an old dog a few new tricks.

After reading the manual, the next step is to identify underground obstructions. Always call an underground locating service before you dig to identify the whereabouts of buried lines. Also, beware of natural obstructions like rocks or tree roots. Grass and other overgrowth can also hamper an auger’s digging ability by clogging the auger blade and screw bit, and therefore should be removed to increase efficiency and overall productivity.

Proper Start-Up

Once all the jobsite parameters have been established, it’s time to get digging. Pay attention to the operating instructions for starting the hole digger’s engine. The machine is designed to keep the operator away from the engine exhaust muffler. With an improper operating position, the operator runs the risk of serious injury from coming into contact with the hot surface of the muffler or from inhaling high levels of carbon monoxide.

Allow the engine to properly warm up to the point where it will operate without the engine choke. Keep in mind that in cold weather, initial starting may require more pulls. Once running, if the hole digger or an individual component or accessory does not appear to be functioning properly, stop immediately and correct the problem before resuming work.

Normal operating procedure for a handheld hole digger is to dig with the engine going at full speed. This allows the unit’s centrifugal clutch to become more firmly engaged, thus transmitting more usable power to the auger. When using a hole digging attachment, proper auger rpm will vary, but generally the operator should feed the auger as fast as soil conditions will allow.

Kickback, Don’t Relax Position

When working in areas with rocks or other obstructions that could be struck by a handheld auger, an operator should be prepared for the occurrence of kickback force. If kickback is anticipated, the hole digger should be operated at less than full speed to ensure a more rapid release of the centrifugal clutch when an obstruction is encountered.

An operator can minimize the effects of kickback through proper body positioning. Keep the left side of the equipment handle as close as possible to your left hip and leg area. Your upper arms should be kept close to the body to maximize mechanical leverage. Keep your back vertical by bending your legs as needed while digging, and position the left foot ahead of the right foot at a comfortable distance. 

Experienced operators who understand kickback sometimes choose to absorb its effects while attempting to use the auger blade to “chip” their way around or through an obstruction. This technique usually involves holding up on the operator handle and establishing a minimum feed rate for the auger. Often the nature and size of a buried object will simply prevent the auger from passing by or going through it, forcing workers to find a more suitable tool to remove it. The main point is that kickback is manageable when proper operating position is maintained, but is equally challenging if the operator is not prepared for it.

Operators would be well advised to wear gloves while running a hole digger and should always keep a firm and steady grip on the handles. This helps to reduce fatigue, as well as increase productivity. If an operator ever realizes that he is in the process of losing full control of the hole digger for any reason, he should push himself free and clear from the handles.

In the Hole

As a general rule, pressing down on the operator handles is not required to initiate or sustain the digging process. In lower density (soft digging) soils, it may be necessary to hold up on the handle to reduce the digging rate of the auger. In higher density (hard digging) soils, an operator might need to press down on the handles to establish acceptable digging rates. Operators should make judgments based on their individual levels of experience to prevent the auger from burying itself in the hole, which is typically the outcome when allowing the auger to feed at an excessive rate.

Occasionally, operators will wind up stopping the engine while the auger rests in a partially or completely dug hole. Only a skilled operator should attempt to restart the engine while the auger remains in the hole. The more accepted procedure is to first remove the unit from the hole, and then return it to the hole with the engine running only at idle speed. One exception for this is during the use of auger extensions.

Extensions are often called upon when standard length augers are insufficient. Using extensions is a vastly superior alternative to feeble attempts of some to force a standard auger to drill down to extreme depths. This error in judgment usually ends with an auger buried in the ground. The mistake is commonly multiplied when operators try to back the auger out with pipe wrenches. When this exercise proves unsuccessful, some try yanking the auger out with a backhoe or skid steer, which almost always results in the auger becoming bent and broken.

Dig No Further

Of course, no amount of operational advice can really substitute for actual experience. Hole digging professionals develop a natural feel for their craft over time. But new equipment innovations are constantly hitting the market, which means it’s always a good idea to peruse the manual or call the manufacturer for operating tips from time to time. With the right combination of experience, common sense and occasional re-education, auger operators can continue to hone their hole-digging skills to get the most out of their equipment on the job.

Dennis Von Ruden is the president of General Equipment Co., based in Owatonna, Minn.