If you're in the market for a table saw, you'll have a number of options and features to consider. To make the best decision, a basic understanding of the "inner workings" of this woodshop standard is essential. Below, I'll describe the primary table saw components, what makes them important, and what to look for when it comes time to buy.
The Table Saw Base - More Than Just a Firm Footing
Heavy Duty Drill
Beginning at the bottom, the table saw base houses the working parts of the saw, including the trunnions, the arbor assembly, the sector gears, and sometimes the motor. On some saws, the base is a "cabinet" type, meaning that a fully enclosed base extends all the way to the floor. Other saws have an open base, meaning that the base consists of a metal box that surrounds the internal working parts of the saw on four sides, but not the bottom. Open base saws have legs that extend downward from the bottom of the base to the floor.
A few recent additions to the table saw market combine features of cabinet-base saws and open-base saws. These "hybrid" saws have both a completely enclosed base and legs. The small, enclosed base of the hybrid saw promotes dust collection and limits noise. A popular choice for hobbyist and small professional shops, hybrid table saws are also lighter and more affordable than traditional cabinet table saws.
Table Saw Motor, Trunnions, and Arbor Assembly
The motor, trunnions, arbor assembly, and gearing make up the essential mechanical components of the saw. These quality and robustness of these components varies considerably and can greatly impact the durability of the saw, its capacity for cutting heavy stock and its ability to stay in adjustment and hold settings.
Most table saws - other than small bench top models - are equipped with induction type motors in the 1 - 5 HP range. On larger saws, you'll most often find a "totally enclosed, fan cooled" (TEFC) induction motor. A TEFC motor is designed for continuous duty and is sealed against dust and other contaminants - a significant advantage in a woodshop.
Saws specifically designed for hobbyists and home use are usually outfitted with motors under 3 HP and can be operated on standard 110 volt residential circuitry. In general, motors in this class are powerful enough for routine cutting of sheet goods and hardwoods up to 1'' thick. Professional-class saws, on the other hand, have motors in the 3- 5 HP range and require a 220 volt power supply. Motors in this category are designed to stand up to hours of continuous duty, and have enough power to cut thick, heavy hardwood stock without bogging down.
The The Table Surface and Extension Wings
The quality of the table saw surface (or "bed") is extremely important to the overall performance of the machine. The table surface needs to be reliably flat and rigid to properly support the workpiece during a cut. As one of the most massive parts of the saw, the table surface also plays a major role in absorbing vibration. Because of the need for mass, rigidity and flatness, cast iron is the material of choice for the top of a table saw. On a quality saw, the table is made using a hefty quantity of cast iron and state-of-the-art foundry methods. The end result of the casting process is then precision ground to flatness in the .0005'' tolerance range.
Many table saws can be purchased with optional extension wings. Table extension wings bolt on to the right and left sides of the table and increase the surface area of the saw to help support wide stock and sheet materials. On a heavy duty stationary saw, the extensions are usually cast iron, while on smaller saws, they may be made of lighter stamped steel or the lighter "webbed" style of cast iron.
One drawback of lighter-weight table extensions is that they have less mass, and the overall mass of the saw is what soaks up the vibration crated by the motor and other moving parts. The added mass of heavy cast iron extension wings decreases vibration, which in turn helps the saw stay in calibration, and also helps it stay planted firmly on the shop floor. On less expensive saws, extensions made of stamped metal, or ones that aren't precision ground, can also compromise the overall flatness of the table surface.
The Rip Fence and Rails
The rip fence guides the wood as it is being ripped (cut along its length) and can be positioned to any width of cut within the saw's range. The fence rides on fence rails attached to the front and rear edge of the table. Ideally, the system keeps the fence perfectly parallel to the plane of the blade, regardless of where the fence is positioned.
The quality and accuracy of fence systems, however, varies greatly across the spectrum. The quality of a table saw's fence system is an extremely important consideration: A poorly designed or inaccurate fence greatly diminishes the quality and accuracy of the cut, and can be a source of significant frustration. For saws in the price range of most hobbyists, the famous Biesemeyer T-square fence design sets the standard. Fortunately, many smaller, more affordable saws come standard with a reasonably accurate system patterned after the tried and true Biesemeyer design.
The Miter Gauge
Most table saws use the miter gauge and miter slot system to allow for crosscutting. A miter gauge consists of a cast metal protractor head attached to a length of metal bar. The bar rides in corresponding "miter slot" in the table saw's surface. Protractor on the "no frills" miter gauges that come with most table saws can be set to crosscut stock at any angle between 90 and 30 degrees and, if well made, do a serviceable job with most "routine" crosscutting.
One of the more useful add-ons for just about any table saw is either an upgraded system offered by the manufacturer, or an aftermarket miter gauge or crosscutting sled. These tools provide, in various combinations, repeatable incremental angle positioning, longer fences, stop blocks and other advanced features that can come in handy in projects that call for precision crosscutting.
Choosing a Table Saw - One Size Does Not Fit All
For an industrial woodshop, where size, space, weight and to some extent cost are not issues, the table saw choice is simple: buy the largest, heaviest, most durable and best performing saw available. For smaller shops, however, an expensive 700 lb. cabinet saw may not be practical - or necessary. Fortunately, many smaller, more affordable table saws are built from high quality components. Great table saw can be found in virtually every size class and power level - you just need to know what to look for.
Black Friday DEWALT DW920K-2 1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver Kit 2011 Deals
Nov 18, 2011 16:34:38
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Black Friday DEWALT DW920K-2 1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver Kit Feature
- 80 in-lbs of maximum torque output provides for a superior power to weight ratio in a variety of fastening applications
- Adjustable two-position handle allows for operation as both in-line and pistol-grip
- variable speed and reversing trigger switch provides 0-500 rpm for fastening and pre-drilling into wood, plastic, and light-gauge metal
- Industrial quick-release hex-shank chuck allows for quick screwdriver bit change and prevents bit run out
- Electric brake provides increased productivity; 7.2-voly battery pack allows for longer run-time and charges in one hour
Black Friday DEWALT DW920K-2 1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver Kit Overview
Fast, efficient, and versatile, the DEWALT DW920K-2 1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver Kit features heavy-duty construction, the convenience of variable speed, and a 7.2-volt battery pack for quick charging and longer run time in small fastening applications. It's ideal for professional use, and comes with two batteries, a charger, bit, and kit box for easy storage and portability.
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 Fasten screws in hard-to-reach places with this two-position screwdriver.View larger. |
 The angle grip allows for comfortable handling in a wide range of tasks.View larger. |
Compact and powerful, this DEWALT DW920K-2 1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver Kit provides 80 inch-pounds of maximum torque output for a superior power-to-weight ratio in a variety of fastening applications.
Variable Speed for Improved Control and Versatility
As versatile as it is robust, the DW920K-2 offers the convenience of variable speed (0 - 500 rpm) to match the correct speed to the job at hand, as well as a reversing trigger switch for fastening and pre-drilling into wood, plastic, and light-gauge metal.
Adjustable Handle for a Better Grip
Designed to be as user-friendly as it is efficient, the DW920K-2 features an adjustable two-position handle that allows for operation as both in-line tool and an angled grip for tight spaces and overhead work, increasing your project flexibility. And a heavy-duty metal hinge provides secure and sustained two-position lock.
Minimize Downtime and Boost Productivity
To minimize downtime, an industrial, quick-release, hex-shank chuck allows for quick screwdriver-bit change and prevents bit "run out." For added convenience, both a 7.2-volt battery pack and an electric brake enhance productivity.
Dimensions and Warranty Information
At 3.5 pounds, the DW290K-2 1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver Kit is lightweight enough for all-day jobs without excessive stress on wrists and hands. It's also backed by a limited three-year warranty, 90-day money-back guarantee, and one-year free service contract.
What's in the Box
1/4-Inch 7.2-Volt Cordless Two-Position Screwdriver, one-hour nicad charger, two 7.2-volt compact nicad batteries, screwdriver bit, and kit box.
 With 80 inch-pounds of maximum torque output, this screwdriver will stand up to a variety of job site tasks. |
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