Power Tools

All you need to know about power tools

Making the grade

The Alliance for Power Tool Performance is expanding efforts to standardize power tool evaluation.

Selecting a power tool for a specific operation can be difficult, because verifiable performance and ergonomic data are not always available.

Such information is crucial, because torque output can vary considerably from tool to tool. In fact, the torque output of some power tools can vary by as much as 120 percent in the same application. This is unacceptable for assembling quality vehicles.

In the 1970s, major U.S. vehicle manufacturers made some efforts to develop uniform testing standards, but few results materialized. The American National Standards Institute (ANSI) did not have a standard for testing power tool performance. In fact, no U.S. industrial organization had a standard for evaluating the performance of power tools, and the International Standards Organization (ISO) did not offer such a standard until 1981.

Instead, each tool manufacturer developed its own methods to show how well its tools perform. If an assembler had performance standards for power tools, tool suppliers were forced to manufacture special tools to meet those individual – and sometimes arbitrary – specifications.

To solve this problem, Ford Motor Co. began an extensive program to test and certify power tools. The program eventually evolved into the Alliance for Power Tool Performance (APTP), a tool-user consortium formed in October 1994 by Ford, Chrysler Corp. (Auburn Hills, MI), General Motors Corp. (Detroit), Boeing Co. (Seattle) and Lawrence Technological University (Southfield, MI). The APTP is expanding standardization efforts for measuring power tool performance beyond current ISO standard requirements.

The Early Days

In the late 1960s, technology was developed to measure torque while securing a fastener. Ford engineers used this technology to study the dynamics of the securing cycle. These studies revealed that the “hardness” of the joint had a significant influence on the transfer of kinetic energy from the tool to the fastener.

Up to that time, Ford engineers had assumed that the tools were the only significant cause of torque variation. Now that a second cause had been identified, a way to measure it had to be found. So, a quantitative measurement of joint hardness, or the increase in torque for one full turn of the fastener after it reaches snugness, was developed. Called the “torque rate” of the joint, this torque measurement is expressed in newton-meters per revolution or foot-pounds per revolution.

Through electronics and software, torque increase during rotation could be graphed and a picture of the securing cycle could be drawn. Thousands of these graphs were generated in Ford assembly plants to determine the extent of torque rate variation in actual production, and to determine the exact hardness or softness of various joints. Analysis of this data showed the torque rate for the same size fastener in different applications could vary as much as 70-to- 1. A hard joint was defined as needing about one-tenth of a revolution to obtain maximum torque, while a soft joint requires approximately 3 revolutions to reach maximum torque.

Ford examined potential combination s of applications, in which one operator used the same tool to secure several different fasteners in several different joints. Often, one operator would need to secure joints with torque rates that differed by as much as 30-to-1.

Armed with this knowledge of actual production conditions, Ford developed laboratory test fixtures that duplicated the extremes in joint rates. The Ford Power Tool Certification Program was started and documented in Power Tool Acceptance Procedure No. PT-2.

Over the years, hundreds of tools were tested and expertise in power tool dynamics was gained. The original test fixtures, which used a nut and stud with a deflecting plate, were found to lack the accuracy needed. Because the lubrication could not be accurately controlled, the precise torque rate could not be repeated for every fastening cycle. This fact, and the mass of the rotating nut, influenced the test results and distorted the true performance of the tools.

In 1980, Ford switched to test fixtures that use a steel torsion bar for the hard joint and a rubber torsion tube for the soft joint. This eliminated frictional influences in the test fixtures and allowed true isolation of the torque variations caused by the tools. The Power Tool Acceptance Procedure No. PT-2 was revised, and tools that were tested on the old fixtures were recertified.

The Ford Power Tool Certification Program has forced tool manufacturers to develop new technology to manage the kinetic energy of the tools they sell to Ford. Ford-certified tools must control the torque variation to within 30 percent of the mean. Some electric tools must be controlled to within 10 percent, and some suppliers are marketing Ford-certified tools as “high-capability” tools. Recent tests of some noncertified tools showed that their torque variation is still as high as 120 percent in the same application.

During the past 20 years, Ford has generated torque and angle graphs on thousands of joints. The equipment to do this has improved dramatically, and the equipment is routinely taken to different plants to do on-the-job analysis. To date, experience has shown that the torque rate variation for fastened joints in Ford assembly plants is still about the same as it was 20 years ago.

Enter ISO

The goal of ISO is to facilitate trade and technology transfer by establishing global standards for similar technologies in different countries. The standards are developed by teams of relevant experts representing suppliers and assemblers. The teams write a draft standard, which is then submitted to the standards organizations of the ISO member nations for their approval. In the United States, that reviewing organization is ANSI.

ISO 5393, Rotary Tools For Threaded Fasteners – Performance Test Methods was published in 1981 and was based on the first-generation Ford standard. In 1987, ISO began working on a major revision of ISO 5393, which was submitted to ISO member nations for approval in 1991. The voting on the new draft resulted in a few minor revisions and additional explanations. The second edition of ISO 5393 was published in May 1994.

In 1986, Ford moved power tool testing from its manufacturing development center to Lawrence Technological University. The test equipment and methods at the university were revised from the Ford standard to the performance test method of ISO 5393 in 1989. Ford’s Power Tool Acceptance Procedure No. PT-2 and rating system were revised, and there is now a third generation of Ford-certified power tools.

The power tool testing facility at Lawrence Technological University is an independent laboratory that can test rotary power tools to ISO 5393. During the past 7 years, the facility has tested tools from 27 suppliers. More than 400 tool models have been tested at more than 1,000 torque settings.

Forming an Alliance

The APTP’s purpose is to provide a single voice to the tool manufacturing industry. Uniform test methods and standards for power tools used to secure threaded fasteners will ultimately benefit all assemblers. It will reduce the complexity and cost of the tools while improving their performance. Using uniform test methods will provide verifiable data on power tool characteristics.

Before the APTP, no organization championed assemblers’ concerns about tool accuracy and reliability. The APTP members want the standards to replace the unique performance specifications developed by Ford and others. Although the primary delegates of the APTP are from the automotive and aerospace industries, representatives from other industries are encouraged to critique the APTP’s efforts and participate in creating standards that will serve every industry that uses power tools.

Already, the APTP has given capability and durability ratings to many brands of power tools.

The APTP rates tools according to their ability to control torque variation to within a certain percentage of a mean torque value. A tool is given an A rating if the torque variation is less than 5 percent; a B rating if the torque variation is less than 10 percent; a C rating if the torque variation is less than 15 percent; a D rating if the torque variation is less than 20 percent; and an E rating if the torque variation is less than 25 percent. Although some air-powered tools received a C rating, most were rated at D or E. Among DC electric tools, a few received an A rating, some received a D rating, but most were rated B or C.

A tool’s durability rating depends on the number of cycles for which it is tested. Tools tested for 1 million cycles receive a rating of 10. Tools tested for 100,000 cycles are given a rating of 1. Most handheld tools are tested for 250,000 cycles, for a 3 rating. Most fixtured tools are tested for 500,000 cycles, for a 5 rating.

Thus, a tool with a rating of E3 can be expected to achieve a torque accuracy of less than 25 percent across 250,000 cycles.

Future APTP projects include certification standards for nutrunners, test standards and methods for pulse tools, standards for electric tool cables, and a durability testing method for tool cables. The APTP is also defining limits for “tool whip” for electronically controlled air tools.

RELATED ARTICLE: APTP Standards for Power Tools

Each tool manufacturer shall certify the minimum accuracy of every tool model number in accordance with ISO 5393 performance testing methods. The certification process includes the following steps:

  • Test data shall be verified by an independent test laboratory through evaluation of at least two production samples of each tool.
  • Tools will only be tested at the torque-test levels outlined by the APTP.
  • The high- and low-test levels shall be clearly and permanently marked in newton-,eyers on every tool. If an internal adjustment is used to obtain the test levels, the approximate adjustment between the test levels shall be visible on the tool.

  • If external air pressure control is used to adjust test levels, the pressure setting shall be marked with the corresponding test level.
  • For electric tools, the electronic default to all the parameter setting certified accuracy.

Each tool manufacturer shall certify the minimum durability of every tool model. The certification process includes the following steps:

  • Cyclic testing of at least one tool should be done at an independent laboratory. Data for the model with the highest torque output may be used to project durability of models with lower torque output
  • Tools shall be tested at the high-torque test level for a given number of cycles. The accuracy test should then be repeated.
  • The certified accuracy and durability of each tool shall be clearly and permanently marked on each tool.

 

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Hand tools and power tools consumers and professionals are trading up to quality

Value and quality are becoming essential factors in selling both hand tools and power tools. With the uncertainty of the economy, contractors and do-it-yourselfers are looking for products that last.

Sales in both the hand and power tool categories rose during 1992, despite recessional pressures. According to wholesale and retail buyers, each category is developing new markets and products.

Power Tools

The buying trend among consumers and professionals concerning power tools is toward better-built products. The consumer power tool market is the scene of dramatic buying trends. Homeowners are looking to invest in better tools to repair their homes.

According to Bob Zerwer, Cotter & Company’s assistant merchandise manager of power tools and accessories, “The consumer is upgrading to more of a professional level of power tools. They know the value of a better quality tool.”

Consumers are also buying higher-end tools because they are better informed. “People surprisingly know a lot about power tools,” says Howard Wenzlaff, co-owner of Paw Paw Ace Hardware, Paw Paw, Mich.

Karl Kleintop, hardware buyer for the Estate of Geo. S. Snyder, Hatfield, Pa., believes the popularity of do-it-yourself television programs, such as “Home Time,” have contributed greatly to consumers’ power tool knowledge.

“The first-time d-i-yer will usually buy the low-end tool,” Zerwer says. “The experienced d-i-yer will buy a better tool to get a longer life from it.”

Increased consumer demand for higher-end power tools is eroding these product’s margins. More people know what these tools should cost and are willing to drive long distances to get the best price, says Paul McNally, retail manager for H.J. Opdyke Lumber Co., Frenchtown, N.J.

Thanks to the intensified competitiveness of this category, retailers are lucky if they can squeeze out a 10 to 15 percent margin, says Joe Smith, hardware sales manager for Linworth Lumber Co., Worthington, Ohio. But Smith says profits sacrificed to low margins can be recouped by cross-merchandising power tools and accessories. Margins on popular power tool accessories, such as drill bits and saw blades, can run as high as 40 percent, he says. Some accessory products produce margins as high as 60 percent, Zerwer notes.

Power tools sell best in the spring and during the Christmas shopping season, which begins in November. When spring arrives, contractors and homeowners buy the tools they need for new jobs and repair projects.

Contractors want quality at a fair price, retailers report. More than ever before, professionals are demanding retailers offer them power tools they can depend on. When tools break or burn out, contractors lose time and money.

Contractors are much more brand loyal than consumers and are willing to pay more for a tool if it is backed up by the retailer and manufacturer with repair and replacement service. They also want to handle and test the tool before making a purchase.

Rick Orlando, vice president of Barr Lumber, Costa Mesa, Calif., holds a buying fair every year where contractors can see products in use.

“Made in America” is evolving into an important power tool selling factor, McNally says. U.S. tariffs on imported tools have also made quality domestic products look more attractively priced. Industry sources report tariffs are contributing to as much as 25 percent of imported power tools’ retail price. According to the U.S. Department of Commerce, import shipments of power tools have decreased from a high of $830 million in 1989 to $764 million in 1991.

Advertising is essential to selling power tools. Customers need to know what you have to offer and that you are competitively priced, McNally explains.

Running the most popular power tools in the store’s regular circulars has worked well for Opdyke’s, McNally says. Some of the most visible power tools include: circular saws, hand sanders, battery-powered drills and nail guns.

According to industry sources, power tools are seeing strong fill rates and availability. The only concern voiced by buyers is that the market may see some temporary shortages this fall if there is strong pre-Christmas retail buying, because many manufacturers have cut inventories to the bone.

Many power tool manufacturers have turned to just-in-time and quick response technologies to reduce costs. Buyers recommend retailers place their Christmas orders earlier than normal to avoid possible shortages.

New products and styles are also making headway in the power tool market. Buyers and retailers agree that brighter-colored tools are gaining market share.

Some manufacturers are offering no-hassle return policies and free one-month trial periods to get contractors and consumers to try new products.

Battery-powered, cordless power tools are gaining greater market share as manufacturers develop more powerful and longer-lasting batteries. New cordless power tools feature fast-charging removable batteries.

When the non-removable batteries in older tools wore out many consumers had a tendency to throw out the entire tool. These new removable batteries can recharge in as fast as 15 minutes to an hour. Older battery models took as long as 16 hours to recharge, Zerwer notes.

Responding to consumer requests, manufacturers are working to develop rechargeable batteries that are interchangeable with different tools. Currently, the batteries and chargers can comprise as much as 50 percent of a cordless tool’s price. Cordless power tool batteries are also much stronger. The new batteries can produce as much as 10 to 12 volts. Older batteries were considered powerful if they produced 7 volts. With stronger batteries, cordless tools can do many tasks only regular corded tools could previously accomplish.

Keyless chucks are another product feature expected to be standard on power drills in the next few years. The keyless chucks simplify bit changing, because there isn’t a key to lose, Zerwer says.

Hand Tools

Hand tools are a great way for retailers to recapture profits sacrificed in low-margin power tool sales. Because most hand tools are blind items, they carry higher margins and require little effort to sell up, retailers report.

The industry is seeing a shift toward greater acceptance of private label tools and newer colors and designs.

Brand loyalty is important to both the contractor and the d-i-y hand tool customer. Hand tools gain acceptance through word-of-mouth recommendations between professional users, Smith explains. “Contractors talk to their buddies who say, ‘hey, this is a good tool.'”

Consumer brand loyalty has enabled larger national chains to gain price advantages over smaller independents. Manufacturers introduced private label brands to correct this disadvantage, but retailers have had difficulty overcoming brand loyalties.

During the past few years, the private label hand tool market has grown through the offering of free-trial periods, no-hassle return policies and lower prices.

Merchandising private label tools with name brand products helps to introduce customers to the value and advantages of private label products.

Traditionally, homeowners have bought more private label products while professionals have stuck closely to brand names they trusted, says Ted Cap, buyer for hand tools at Ace Hardware Corp. But retailers who aggressively promote the comparable quality and price advantages of private label tools are seeing more contractors crossing over to try unfamiliar brands, Cap says. Manufacturer-sponsored promotional aids, such as full lifetime warranties, are great at hooking crossover sales.

Utility is a major selling factor for hand tool customers, Smith says. A good example is hammers. In hammers, vibration is a major factor to consider. The more a hammer vibrates during use, the faster the user’s arm tires and the less they can accomplish.

Smith directs professional customers to buy a low-vibrating, higher-end steel handled hammer. For homeowners who want a hammer to hang an occasional picture frame, he recommends a higher vibrating, but less expensive wooden handled model.

Manufacturers are redesigning the handles and grips of many of their hand tools to make them safer and easier to use. Some manufacturers are also beginning to give smaller, easily misplaced tools, such as utility knives, bright colors.

The colors enable the user to find the smaller tools if they are dropped on a cluttered worksite or in a tool box. These tools now come in bright yellow, lime and orange, called “safety colors.”

These new colors are becoming popular with both contractors and consumers. Because they stand out, they make excellent endcap and dump bin promotional items.

Electronic stud finders are a redesigned product seeing strong consumer sales, Wenzlaff explains. They also make great impulse items.

The most price-sensitive hand tools include: hand saws, screwdrivers and screwdriver sets, reciprocal saws, 25′ tape measures, hammers, carpenter squares and levels.

Both consumers and professionals have a good idea of what the most basic hand tools should cost, retailers say. But the myriad of other tools and accessories are ideal items to variably price.

Buying Tips

* Accessory sales for circular saws have been boosted by the introduction of improved, thin-kerfed blades, which also offer higher margins.

* Tool sales tend to correspond to the strength of the housing market.

* Buy earlier than usual for the 1993 Christmas season. Buyers predict possible shortfalls, if retail ordering is heavy.

* Top tool sales periods are spring, Father’s Day and Christmas.

 

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Cordless tool makers power up to meet market demands

The demand for the power of cordless tools without the cord has given birth to another growth phase in battery-operated power tools. Cordless sales in the United States, the fastest-growing segment of the market, skyrocketed from $217 million in 1992 to $575 million in 1995, according to Randy Watkins, marketing research manager for Porter-Cable, one of the industry’s leading power tool manufacturers. James White, president of Jackson, TN-based Porter-Cable, says cordless tools make up 21% of the total power tool market.

In the last three years, tool makers have scrambled to match current technology with consumers’ seemingly insatiable thirst for power. The result: higher-voltage cordless power tools entering the market at a rapid rate.

Power source

Energizer, Panasonic and Sanyo–the three top suppliers of nickel-cadmium (Ni-Cad) batteries–represent the front line in cordless technology. Experimentation with lithium-ion (Li-Ion) and nickel metal-hydride (Ni-MH) may shift the industry from Ni-Cad, but probably not anytime soon. “Ni-Cad’s very robust, easy to manufacture and easy to control.” says David DeVries, Ni-Cad product manager for Energizer Power Systems in Gainesville, FL. Ni-Cad’s durability, performance and cost match the cordless power tool market, he says. Li-Ion and Ni-MH, for now, cost too much to manufacture in mass quantities, he says. “Very few people are willing to pay $300 for a drill.”

No cords, no hassle

As d-i-yers and pros increasingly find themselves with less free time and an eye for convenience-oriented products, their desire for better-working cordless tools has grown. “What once was a convenience is now a necessity,” says Bob Chalfant, product manager for Ryobi North America. “Every professional contractor now has a cordless gun.”

The d-i-y market drove cordless sales in the category’s infancy because contractors claimed cordless products didn’t generate enough torque (power), nor did they run long enough between charges. The balance between high torque and longer run-time boils down to motor technology and battery research. That’s a difficult balance. “You can either have a lot of torque or a longer run-time,” says Charles Schaefer, a product manager for Makita U.S.A. “You can’t have both.”

Recent advances enable contractors to get the power of a corded tool with the convenience of cordless. Though many pros still prefer familiar corded products, they’re increasingly leaning toward battery-powered tools. Some sources say pros are switching away from corded products in large numbers.

Contractors’ Warehouse president Dave Krawczyk says contractors replacing their old corded tools with cordless models creates “a whole new market.” New battery upgrades in voltage and amperage now offer contractors tools to handle all their jobs, he says.

Twenty years ago, power tool manufacturers began offering 4.8- and 7.2-volt cordless drills. By the end of the 1980s, companies introduced 9.6- and 12-volt cordless tools. “Makita (U.S.A) ruled the market a few years ago with its 9.6-volt line,” says Ken Stieler, owner of Bozeman, MT-based Four Corners Trustworthy Hardware. “Now 9.6 sales are almost non-existent.”

Engineering developments accelerated introductions of 14.4- and now 18-volt cordless tools. Though a 12-volt drill/driver will handle most jobs, consumers and contractors want more power.

‘Tim Allen Syndrome’

“They want the biggest, best and latest,” Stieler says. He and other industry sources dub it the “Tim Allen Syndrome”–referring to the ABC sit-com Home Improvement, in which character Tim Taylor, played by Allen, constantly concocts ways to make his tools generate “more power.”

Four major manufacturers–Makita, Ryobi, S-B (Skil/Bosch) Power Tools and Porter-Cable–expanded their offerings with 14.4-volt tools during 1996 to meet the demand for more power.

 

Stielers anticipating 14.4- and 18-volt sales to pinch sales of 12-volt models. “I’ve seen 14.4 sales really increase in the last year,” he says.

Towson, MD-based DeWalt Industrial Tools launched its 18-volt line in March, which includes two types of drill/drivers and a circular saw. Prior to DeWalt’s 18-volt introduction, only four companies offered e drill/drivers with voltages higher than 12–DeWalt and Sears with 14.4s, and Freud and Wen with 13.2s.

Previous attempts at 24-volt tools failed to generate interest because of bulky fanny packs and/or weight problems. Bosch’s new 24-volt rotary hammer drill weighs between 7.7 and 9 pounds–depending on the battery’s Ampere hour (Ah) capacity of 1.7 or 2.5 hours. The hammer drill’s best suited for heavy-duty industrial tasks, and is marketed also as a rental product.

While manufacturers have discovered that “more power” sells, it’s not at the expense of other powertools. DeWalt’s director of product management Chris Metz says there’s been no cannibalization of lower-voltage products or in the corded category. “It’s just expanded the market,” he says.

The sky’s the limit?

Where does it end? The limit appears to be 18 volts in most power tool types. Bosch’s 24-volt rotary hammer drill, the possible exception, generally requires two hands to operate properly, putting this tool in a different category.

“Bigger is not always better,” says Ryobi’s Chalfant, who adds weight will limit high-voltage tools to 18 volts.

DeWalt’s Metz agrees. “We hit the theoretical weight limit with 18 volts,” he says. DeWalt will now try to expand its 18-volt line to other types of tools, he says. Likely candidates include jig saws and reciprocating saws.

D-i-yers shop like pros

Though designed for contractors, DeWalt’s 12-, 14.4- and 18-volt tools draw d-i-v interests. “We know there’s a lot of d-i-yers stepping up to pro-grade tools,” Metz says, “but that’s not who we make them for.”

David Levine, vice president/GMM of Melville, NY-based Pergament Home Centers, says DeWalt powertools represent the “hottest” items in the convenience-oriented chain’s hardware department. D-i-y homeowners-now more knowledgeable about home projects than their predecessors–may not necessarily need the power of pro-grade tools, but they’re definitely buying them. k

 

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Buying a Bench-top Table Saw

Buying a table saw used to mean shelling out a pile of cash for a big, heavy machine and then carving out a more or less permanent space for it in your garage or basement. Now there’s a new breed of table saw that’s light, portable and less than half the cost of its big cousins. These “bench-top” saws are Small enough to store on a shelf, light enough to toss in your trunk and powerful enough for everyday cutting tasks, but they do have limitations. We’ll help you decide if a bench-top table saw is right for you, then show you what features to look for and how to compare saws and choose the one that’s best for you. See “The Bottom Line,” p. 84.

Look under the saw to see how the motor is mounted; stronger is better

  • TILT THE SAW back and take a close look at the bracket that supports the motor. This saw has a cast aluminum motor mount bracket and precision gearing that moves the motor up and down steel shafts.

A bench-top table saw is little more than a hand-held circular saw mounted upside down under a table. Better saws have cast aluminum motor mounts that are more rigid than the stamped steel mounts found on less expensive saws (Photo 1), and this translates to less blade deflection for smoother, straighter saw cuts.

Compare motor mount mechanisms by tilting the saw back and taking a close, hands-on look at the underside. You don’t have to be a mechanical engineer to see the difference in quality. Keep in mind that almost every cut you make will require adjusting the motor and blade position. These parts get a lot of wear and tear and are directly responsible for the quality of the cut.

Look for a saw with a solid miter gauge for accurate miters and crosscuts

  • SLIDE THE MITER GAUGE on this Delta saw back toward you and you’ll see the benefit of the t-slot that keeps the gauge from falling out. Adjust the stop screws for precise 90-degree and 45-degree cuts by screwing them in or out. The 3/4-in. wide slot accepts standard accessories.

Cross cutting isn’t a table saw’s best feature no matter what the price, but if you intend to use a table saw for precise angle cuts, the miter gauge should have adjustable stops at 90 and 45 degrees and fit snugly in the table top groove (Photo 2). Slide the gauge along the slot. It should move easily with no side-to-side play. The Delta saw shown has a T-slot to keep the gauge from falling out when it’s pulled beyond the edge of the table. A full-size 3/4-in. wide x 3/8-in. deep slot, the standard size for contractor and cabinet table saws, is essential if you want to use cabinet-making accessories like a tenoning jig.

(By the way, if you own a power miter box for making crosscuts and miters, then having a good miter gauge isn’t as important.)

Look for smooth, easy-to-run cranks and a switch that’s easy to shut off quickly

  • TURN THE CRANK to raise and lower the blade. Look for smooth, easy operation. Unlike most saws, this saw also has a knob that tilts the blade. The large orange switch requires a special procedure to turn on, but turns off with a quick swat. Remove the black button to lock the switch.

Nothing’s more frustrating on these little saws than cranks that are hard to turn, levers that knock your knuckles or switches that you have to grope for. Crank the blade up and down. You’ll want a saw that moves smoothly and is easy to crank. Now try tilting the blade. On most saws this is accomplished by flipping the lever behind the crank to loosen the motor and then pushing the lever to tilt the blade. It’s hard to get a precise bevel setting with this system. Makita solved this problem by adding a wheel that you turn to adjust the angle (Photo 3). Saws with better-quality motor mount mechanisms are the ones that adjust easily and smoothly.

Try out the switch. To deter inquisitive children, the best switches are a little tricky to turn on. For additional protection against unauthorized use, most switches can be locked. For example, pulling out a plastic pin on the Makita disables the switch (Photo 3), which is great (if you don’t lose the pin!). Some saws require you to provide a small padlock or similar locking device.

For safety, the best switches can be turned off with a quick swat. In an emergency, you’ll want to be able to stop the saw instinctively, without having to look for the switch or grope to find it.

Look for a table saw with a dust collection port

  • HOOK UP A VACUUM to the back of the saw to collect dust. Some saws have a built-in dust collection port that allows you to connect a shop vacuum. This is a big plus if you’re sawing indoors.

Many of the table saws have a port to attach a shop vacuum hose (Photo 4). This is a handy feature if you’re working inside and want to catch at least some of the dust before it spreads.

Look for a smooth-adjusting fence with an accurate lock-down

 

  • TURN THE KNOB on this DeWalt to make precise fence adjustments. The unique rack-and-pinion system keeps the fence parallel to the blade, and the extended rails make this one of the few saws capable of cutting a 4×8 sheet of plywood in half. The maximum width of rip is a little over 24 in., while most saws top out at 12 in., wide or so. This is the only bench-top saw with an exceptional fence.

A table saw without a good fence is like a drill without bits. You’ll be adjusting and locking down the fence for almost every cut you make, and a crummy fence will try your patience and can be dangerous. You’ll be able to tell a lot about the quality of the fence by sliding it along the table and locking it in place. Better fences slide easily and lock down solidly. Grab the end of the fence farthest from the front of the saw and try to move it back and forth. It should stay put.

DeWalt has done a great job of designing a fence that adjusts easily, stays parallel to the blade and locks down tight, but you’ll pay about $500 for this saw. Fences on the mid-priced saws lock down firmly but usually require you to align the fence with the saw blade every time you change the ripping width. Some less expensive saws have flimsy fences that won’t stay put. Besides giving you a bad cut, a fence that slips or moves while you’re ripping can cause the board to bind and kick back, presenting a serious safety hazard.

If you think you’ll use your table saw to rip plywood for shelves or cabinets, check out the maximum ripping width. This is determined by how far the fence can be set from the blade. The range is from a low of about 10 in. to a whopping 24-1/2 in. on the DeWalt, with most saws being able to rip about 12 in. wide.

Look for a saw that accepts dado blades

  • LOOK FOR A SAW that accepts dado blades if you intend to do cabinetwork. Most will hold up to a 1/2-in. wide set of dado blades. Some, like the DeWalt shown here, accept up to 13/16-in. wide blades. DeWalt provides a second wrench to keep the arbor from spinning while the blade nut is tightened. This is a feature worth looking for

With a set of dado blades, you’ll be able to cut grooves, called dadoes, with your table saw. By stacking the right number of blades on the arbor, you can cut dadoes from 1/4 in. to 13/16 in. wide in one pass. Check the saw manual to see if the saw accepts dado blades and what other accessories, like a different throat plate, you’ll need to use them.

Look for a saw you can lift without breaking your back

  • LIFT THE SAW to see how easy it will be to move around. Some of the saws are real brutes. You may need help moving the heavier saws.

These saws range from a lightweight 36 lbs. to about 75 lbs., and it’s not surprising that the more expensive the saw is, the heavier. Once again the midpriced saws offer a nice compromise, being heavy enough to stay put when you’re pushing a board through, but compact and light enough to toss into your trunk or lift onto a shelf.

RELATED ARTICLE:

No saw is perfect, so look for one with the features you need

A bench-top table saw is ideal for ripping (cutting a board lengthwise to make it narrower), but cutting down large sheets of plywood or cutting long boards to length is a different story. These tasks are difficult to accomplish on any table saw but almost impossible on a bench-top saw.

There are at least 15 different models of bench-top table saws on the market, and none of them is perfect for every person. In general, the more you spend, the better the features.

Narrow the field by deciding how much to spend

We list most of the available saws on p. 84. The saws on the low end of the scale, say from $150 to $200, are generally lightweight. They also tend to have less durable motors and less accurate fences and controls than more expensive saws, but they’ll work fine for light-duty work and cutting thin wood (less than 1 in. thick) for birdhouses and craft projects.

In the middle of the price range are bench-top saws used by many professional carpenters. That’s because these saws are powerful enough to rip through 2x4s day after day but still compact and light enough to be easily thrown in the back of the truck.

There are only a few saws in the higher price range. They offer better fences and features not found on less expensive saws, but you’ll pay for these in extra size and weight.

Most motors have plenty of power, but some run smoother and last longer

Saws that cost more generally have better-quality motors that last longer and run smoother. Some even have brakes built in to stop the blade fast when you’re done cutting.

There are a few things you can do to help your saw cut faster and last longer. If you bought a saw with a 10-in. blade that bogs down when you rip 2x4s, try installing a thinner 8-1/4 in. blade instead. Also, check out the manual that came with the saw for extension cord requirements. In general, the shorter and heavier gauge the cord, the better your saw will run and the longer the motor will last.

The Bottom Line

The bottom line is this. You can buy an excellent quality bench-top table saw for about $300 that will do 90 percent of what you’ll want a table saw for, but don’t plan on building cabinets or fine furniture with this saw. For this type of woodworking, you’ll want to consider spending a few hundred dollars more for the best bench-top saw or a good-quality, contractor’s table saw.

 

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Black & Decker opens a huge – and hugely successful – new DC

Intent on leapfrogging its competitors, Black & Decker — a leading manufacturer of small appliances and power tools — set out in 1995 to consolidate several warehouses into a single high tech distribution center. Two and a half years later, its new DC is world class in every respect. But the DC and its people were tempered by fire getting there.

On the morning of January 31, 1995, Black & Decker‘s new 776,000 sq ft distribution center — designed to handle 85% of the company’s product volume — processed its first live order. Fifteen hours later, 40 people had shipped a grand total of 30 cartons. Thus ended the first of many long days to come.

Fast-forward two and a half years: In June 1997, during one 24-hour stretch, the center’s 12 supervisors, 275 full-time associates, and 100 temporaries shipped, on 175 trucks, some 70,000 cartons of product on full pallets, 70,000 palletized loose cartons, and 5,000 repacked cartons containing 125,000 picked pieces. Total product value: about $18 million. That same day, the DC received 70 incoming trucks and putaway their products.

“I’ve lived through four distribution center startups and they’ve all been interesting,” says Scott Richardson, plant manager. “This one was the most challenging.” Richardson was brought on board a year into the startup.

Nothing but the best

The 60-dock-door DC in Fort Mill, S.C., is state-of-the art. A sophisticated warehouse management system (WMS) runs it. The building houses two 300-ft long, 450 fpm sliding-shoe sorters, five 3-story pick-to-belt modules, including one using high-density dynamic flow racks (Loadbank International). Moving about the building are more than 100 RF-directed vehicles, including 20 wire-guided, narrow-aisle, high-bay trucks.

“By replacing our smaller, older, low tech distribution centers, the company has controlled transportation Costs by reducing the number of trucks on the road,” Richardson says. “Consolidation has also cut the amount of product carried in inventory and increased shipping capacity.

“Black & Decker ships to store and to customer distribution centers,” Richardson adds. “Stores range from mom-and-pop outlets to `big box’ discount centers. Order sizes range from one item to multi-truckloads. As most manufacturers of consumer products have discovered, stores today are interested in consistent order cycle time as opposed to overnight service. This has eliminated the need to disperse DCs. Stores also tend to order more often in smaller quantities.

“New, highly automated distribution centers can more easily and cost-effectively handle wide variations in order sizes and frequencies as well as provide the special services — ASNs, anti-theft protection, etc. — now demanded by many retailers,” he adds.

Building rises rapidly

According to Scott Telk, facility equipment and engineering manager, designing and building the new DC proceeded quickly and efficiently. From project release to startup took only 18 months.

“Then came the first milestone event,” Telk relates. “Immediately on startup, the Household Division’s old DCs were closed because the new DC was expected to be fully operational within a few weeks. In hindsight, the rampup should have allowed for a more controlled phase-in as additional divisions, products, and customers continuously increased processing volumes and complexities. If the old DCs had remained in place, the slower than expected ramp up might have appeared seamless from the outside.

“A realistic timetable would have been at least 18 months of startup, with volume increased gradually from one bottleneck to the next,” the manager continues. “Looking back, I can see we had originally anticipated only about 50% of the facilities issues. Testing and planning can’t integrate systems, equipment, and people without having live orders in growing volumes.”

Many opportunities

In the beginning, the DC’s problems were systems related. The mix quickly evolved to perhaps 20% systems, 30% mechanical, and 50% operational difficulties. Today, however, most issues concern meeting new or changing customer requirements.

A typical operational improvement involved resolving “no-read” bar code scans. Black & Decker also replaced conventional flow racks in its highest activity, pick-to-belt module with deep lane, air activated, pulsed flow dynamic racks. This system has nine pallets of cartons against the pick face so pickers and replenishers can keep up with demand.

Ironically, one of the most challenging startup issues is now the plant’s greatest asset. The WMS production planning process preplans and converges waves of product on the shipping dock from four sources-cartons from the five pick-to-belt modules, full pallets from reserve storage, non-conveyable/ overweight items, and unit picks from 20 horizontal carousels for repacking. All pallet trucks are RF directed by priority. The timing and balance between departments to get the products to an outbound truck at the same time is the deciding factor in process flow control.

A very sophisticated plant

Bruce Kroeschell, logistics systems manager, believes that Fort Mill is one of the first facilities to utilize highly automated push distribution methods in a pull environment. “We mimic pushed retail distribution but without the dedicated trucks/trailers, fixed shipping schedules, knowledge of the next day’s orders, or any way to control order profiles,” Kroeschell says. “Pick-to-belt product largely drives the system because of its volume and higher labor needs.”

High speed sorters deliver the picked-to-belt cartons and carousel repack totes to the loading dock; fork trucks bring the pallets and non-conveyables. Loose pallet loads are hand palletized and auto shrink-wrapped in a very compact dock area. There is no staging, manual sorting, carton scanning, or checking.

“The system plans each pallet in terms of content, cube, and weight before picking, creating advanced shipping notices (ASNs) on a pallet-by-pallet basis,” Kroeschell adds. “Five turns per day per door can be shipped today at up to 99.8% accuracy. UPS takes about 50% of orders but only 5% of cartons.”

Temps add to challenge

Because speeding startup was urgent, the company threw hundreds of temporary workers at bottlenecks to ship sufficient product by brute force until the automation could catch up. Bottlenecks shifted around the plant from wave to wave and as volumes varied. Careful wave planning did little to smooth the order profiles because throughput depended so much on trailer planning. One wave might be mostly pallet picks, another carton picks.

“The temporary employee approach did hold the fort, but at tremendous cost,” Richardson recalls. “Introducing large numbers of temps into a high tech environment delivered less than optimal results in terms of order accuracy and completeness, efficiency, safety, culture, and equipment use. It also introduced new problems. Regardless, shipments never fell more than five to six days behind.”

Logistics systems manager Kroeschell recalls that, because the plant is highly automated, the company originally believed that large numbers of temporaries might fit in well because computers would be in control. Not so, as it turned out. There are just too many special requirements involved.

The company underestimated the numbers of supervisors needed, as well as their training and experience. Especially during startup, a supervisor can train and direct only a few employees. More supervisors should have been hired while the plant was being built so they could familiarize themselves with equipment and systems. A number of mechanics were hired early and they helped install equipment, but more would have been better, Richardson observes.

WMS brings it together

Customer orders are collected by an order management system at the Household Division and Portable Tool Division headquarters. Order turnaround time is approximately 70% within 24 hours of wave planning, 100% within 36 hours.

The WMS is very sophisticated, Richardson emphasizes. “Work can be fully directed by computer, or it can be a mix of fully-directed and supervisor-directed.

“Presently most efficient is a hybrid arrangement that computer-directs detail work, while the overall plant switches between computer and supervisor control depending on how queues develop,” the manager says. “The plant typically sees a 4:1 ratio in shipping volume between the most active and least active days in a month, making hybrid control effective.”

“WMS based inventory profiling has proved essential to our operations,” Kroeschell says. “The technique regulates the storage characteristics of every incoming pallet and of every product. The final weight and cube of each manually built pallet on the shipping dock is calculated during wave building to most efficiently cube out customer orders and trailers. Product weight and cube calculations are used to determine payments to carriers as well.”

The exact numbers of cartons and repack totes are directed to each sorter lane for each pallet built. Obviously, new products, SKUs, packaging, and palletization configurations must be measured and carefully kept in the database. Database “flags” also must be set to distinguish between unit, master pack, carton, full pallet, and non-conveyable/ overweight products.

During wave picking, strips of barcoded, self-adhesive, picking/ shipping labels printed in the pick sequence order are generated in various areas of the plant. One of the labels is attached to each carton, pallet, and tote-borne product as it is picked. A UPC code is already placed on picked item packaging (or there is a customer-specific code in some situations).

Conveyed cartons pass at 450 fpm beneath a barcode scanning station having eight scanners that view all carton surfaces and compare UPC and product codes for matches. The station also transmits data to the control systems for the 24-lane primary and secondary sliding shoe sorters immediately following. The scanning station is believed to be the first in the U.S. to scan and relate so many sizes and types of bar codes.

Expectations met

“Because our systems, machines, and people now perform to expectations, the new DC is meeting its original capacity goals,” Richardson says. “Efforts at improving operations are concentrated on upping accuracy above 99.8% and also on meeting customer needs.

“Trying to meet today’s volumes using our past distribution methods, especially in light of our current customer service demands, would require a much larger investment in space, inventory, labor, and transportation,” he asserts.

“The monetary and customer relations costs to Black & Decker would have been intolerable and would have seriously threatened the company’s leading position in its industry.”

 

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Bench grinders the sharpening, cleaning and buffing tool

“If someone gave me eight hours to cut down a tree, I’d spend six hours sharpening the axe.”

Abraham Lincoln

Sure, preparation is important, but Abe could probably have cut his sharpening time down to 15 minutes with an electric bench grinder.

Bench grinders are essentially a maintenance tool because they excel at sharpening, shaping, scraping, cleaning and polishing metal, plastic, and to a lesser degree, wood. It’s a “must-have” tool for welders, hobby farmers or those who putter on cars, motorcycles or engines–and once serious DIYers and woodworkers get their hands on one, they put it to good (and frequent) use.

Bench grinders are categorized by the diameter of the grinding wheel they use. They cost anywhere from $45 for a 5-in. homeowner’s model to $300 for a heavy duty 8- or 10-in. model. A 6-in., 1/4-hp model (around $75) can handle most homeowners’ tasks.

Just like sandpaper, grinding wheels are graded coarse, medium, fine or extra fine. Coarse wheels cut the quickest but leave a rougher edge. Most people mount a medium or coarse stone on one shaft of their grinder for rough work and a fine stone or wire brush wheel on the other for delicate tasks.

AS A SHARPENING TOOL

Their aggressiveness makes bench grinders ideal for sharpening lawn mower blades, hedge trimmers, axes and other hefty tools. For finer sharpening, such as kitchen knives or scissors, you’re better off using a file or whetstone (see “Sharpening Everyday Tools,” Sept. ’91, p. 35). Bench grinders can overheat and destroy such delicate tools. For tools in between–spade drill bits, chisels or plane blades–you can use a grinding wheel, but use a fine stone and work carefully.

Adjust the tool rest so the tool’s cutting edge contacts the grinding wheel at its original angle (Photo 1). The tool rest should be no more than 1/8 in. away from the wheel; otherwise you risk jamming the tool between the wheel and the tool rest, or worse yet, launching the tool into the air.

Start sharpening by making one light pass, then examine the tool to see if you’re matching its existing angle (use the marker test in Photo 2 to make sure). Make a series of light passes, rather than a few heavy-handed ones. If you need to remove a lot of metal, dip the tip of the tool into water frequently to cool it.

 

 

As you sharpen, bear in mind:

  •  If a straw-colored or bluish halo appears near the edge of the tool, you’re grinding too hard or too long and overheating the metal; you risk ruining the temper or hardness of the tool.
  • Remove burrs from the back side of a newly sharpened edge with a sharpening stone (Photo 3).
  • Hold small parts, like screws or brackets, with a Vise-Grips locking pliers.
  • The better you can see, the better your results, so shine a light directly on the tool rest and examine your work with a magnifying glass.

OTHER ACCESSORIES AND USES

Grinding wheels can also be used to clean up jagged metal edges, shorten bolts or smooth welds.

Other common wheels and their uses include:

Wire wheels (Photo 4) are ideal for removing rust or paint. Occasionally remove the wheel and reverse its spinning direction so the wires don’t get bent too far in one direction and lose their effectiveness.

Buffing wheels (Photo 5), stiff or flexible, are ideal for polishing lamps, hardware and other metal objects. You must apply a buffing compound (different kinds are available for different metals) to the wheel before use.

Tool guides are available to hold drill bits and other tools at precise angles during sharpening; I personally haven’t had much success with these.

 

 

DRESSING THE WHEEL

Grinding wheels are made up of small, hard grains or grit held together by a bonding agent. As a wheel works, these grains become dull and fall off, exposing sharp new ones. If the dull grains don’t fall off or if metal particles stick to the wheel, a glazed surface is created. Such wheels cut poorly or not at all.

Dressing a wheel (Photo 6) exposes new grains and removes soft metals. A wheel dresser can also be used to flatten the grinding face or “true up” a lopsided grinding wheel.

Hold the dresser on the tool rest, then work it back and forth for 5 or 10 seconds. Serious sharpeners dress the wheel every time they use it.

SAFETY TIPS

A bench grinder is a safe tool when it’s used correctly. But remember:

  • Never wear loose clothing, gloves or a tie; loose material could catch on the wheel and pull you into it.
  • Always wear safety eye wear with side shields.
  • Examine the wheel before use; if you see cracks or chips, discard it.
  • When you turn the wheel on, always stand out of its way and let it run for one minute before use. Wheels are rarely damaged in normal use; most are damaged in shipping or from being accidentally struck while not in use. If a wheel is going to break, chances are good it will break within the first minute of use.
  • Never grind on the side of your wheel.
  • Never use your grinder around flammable liquids.
  • Use paper washers and metal mounting flanges on each side of the wheel to absorb pressure and vibrations. Tighten the mounting nut just enough to hold the wheel firmly.

 

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