Choosing the best primary breakdown saw

Sawmills deal with highly variable raw material and end products. The sawmiller is expected to manufacture end products with precision in the least time with the lowest cost. The correct selection of a saw for the primary breakdown job is a critical decision.

The costs for raw materials have increased while the average price sawn products has not increased at the same rate in recent years. The efficient conversion of raw materials to sawn products is now more important. Many sawmills have become conscious of the fact that total production costs do not decrease continuously when feed speed increases. Production does not equate with efficiency. Obviously, most of the money in a sawmill is earned by converting as much of the raw materials as possible into sawn products. The best place to start increasing efficiency is with the primary breakdown machine and saw.

The saw must be set up and operated within certain parameters for efficient and balanced performance. The interrelationships of raw material, end product, machinery and the sawing process are essential. Often these interrelationships are ignored when a saw is chosen. One is often chosen for immediate availability rather than by experience and an understanding of the technology.

Saws must be chosen to meet adequately the objectives in conversion of raw material to end product. Correct bite, feed speeds, tooth speeds, side clearances and power requirements should be considered with the density of the raw materials and average depths of cut.

Bandsaws

The variables of efficiently producing sawn products are influenced by the interplay between the raw material, the saw blade and the machine. The bandsaw at work with the machine is a series of complicated relationships including blade strain, residual stresses from blade tensioning and variations from stresses when the blade runs over the wheel.

Circular saws are a mainstay for cutting two-by-fours, plywood, and the like.

A circular saw is an essential too for any but the most rudimentary workshop. Most models run on an electric motor. A few models are battery powered.

WHAT'S AVAILABLE

Black & Decker, Craftsman (Sears), DeWalt, Makita, Milwaukee, Porter-Cable, and Skil brands account for most of the circular saws sold.

Corded models. These models run on an electric motor that can range from 10 to 15 amps. The higher the amps, the more power you can expect. Most models are oriented so the motor is perpendicular to the blade. Another type uses a "worm drive" design in which the motor is parallel to the blade. That design gives a saw a lot of power, but at the expense of speed. Prices range: $40 to $140 for electric saws; $200 to $480 for battery-powered saws.

Battery-powered models. These use 18- or 24-volt motors. They're more expensive than corded models. Price range: $140 to $160.

* KEY FEATURES

Every saw has a big main handle, which incorporates the on/off switch, and a stubby auxiliary handle. Some saws include an interlock you have to press before on/off switch will work. This adds a level of safety, but can make the saw awkward to use.

Inexpensive saws have a stamped-steel base and thin housing; pricier models use thick, rugged material that stands up to hard use. A blade with two dozen large teeth cuts fast but can splinter the wood; a blade with 40 or more teeth gives a cleaner cut. The thinner the blade, the faster the cut and the less wasted wood.

Bevel adjustment is used to change the angle of the cut from 0 to 45 degrees. The depth adjustment changes the blade's cutting depth. A circular saw works best when the teeth just clear the bottom of the wood. The notch in the base plate that is in line with the saw blade is the cutting guide, which helps you follow the cutting line you've drawn on the wood.

A blade-lock button keeps the blade from turning when you change blades. The dust chute directs the sawdust away so you can see what you're doing.

* HOW TO CHOOSE

Performance differences. Seconds count if you have a lot of wood to cut. Speed also affects safety; you're more likely to push a slow saw, dulling the blade quickly and overheating the motor, or making the saw jam or kick back. Typically, slower saws come with a steel blade while carbide blades are on the fastest models. Most corded saws have adequate torque for any typical home-workshop job. Battery-powered saws are much weaker. A weak saw could strain when used on thick hardwood or for other tough work.

Design points that can make a saw easy to use include a visible cutting guide, a blade that's simple to change and to adjust for depth and angle, good balance, a comfortable handle, and a handy on/off switch. How well the saw is constructed impacts its potential for a long, trouble-free life. It should have durable bearings, motor brushes that are accessible for servicing or replacement, a heavy-duty base, and rugged blade-depth and cutting-angle adjustments.

Recommendations. Judging from CONSUMER REPORTS tests, you can get a fine saw for as little as $60. For $120 to $160, you can get an excellent model.

A battery-powered saw lacks the might for tough jobs but might do for occasional light work.

Whichever you buy, if it comes with a steel blade, replace it with a carbide one. Be sure to match the number of teeth with the material you want to cut; a blade for plywood, say, has more teeth than one for rough cutting.

All the saws are loud enough when cutting to warrant hearing protection. All kick up a lot of chips and dust, so safety glasses or goggles are a must. You may also want to wear a dust mask, especially when cutting pressure-treated lumber. Related CR report: August 2002

You  can click here to get more information  about Miter saw 

circular saws are a mainstay for quickly cutting the two-by-fours and plywood used in many popular home-improvement projects

Indeed, circular saws are the most common home power tool after drills. Battery-powered saws offer go-anywhere convenience, but plug-ins are far more capable.

WHAT'S AVAILABLE

Black & Decker, Bosch, Craftsman (Sears), DeWalt, Hitachi, Makita, Milwaukee, Ridgid, Ryobi, and Skil brands account for most of the circular saws sold.

Corded models. These offer up to seven times the speed and power of cordless saws and run on an electric motor that can range from 10 to 15 amps. The higher the amps, the more power you can expect. Most models have the motor perpendicular to the blade. Price range: $30 to $175.

High-torque worm/hypoid-geared models have the motor parallel to the blade. That provides more twisting power, or torque, making the blade less likely to bind in dense or thick wood. But sawing tends to be slower, since blade speed is reduced. They're also relatively heavy. Price: $150 to $175.

Cordless models. These range from 18 to 28 volts. The blade is usually smaller than corded models' and run time is limited by the battery. Price: $60 to $300.

FEATURES THAT COUNT

Every saw has a large main handle and a stubby auxiliary handle; the main handle incorporates the saw's on/off switch. Some saws include a safety interlock, a second switch you must press to turn on the motor. While it helps prevent accidental startups, it can make the saw awkward to use.

Inexpensive saws have a stamped-steel base and thin housing; pricier models use thicker, more rugged material such as reinforced steel for harder use. A blade with two dozen large teeth cuts quickly but can splinter the wood; a blade with 40 or more smaller teeth gives a cleaner cut.

Bevel adjustment is used to change the angle of the cut from 0 to 45 degrees or more for some saws. Depth adjustment changes the blade's cutting depth. A circular saw works best when the teeth just clear the bottom of the wood.

A visible blade located to the left of the motor or a notch in the upper blade guard helps you see the blade and your cutting mark without leaning over the saw. Because the motor on worm-drive saws is parallel to the blade, it's easier to see your cutting mark--a reason pros like them. Many models include a laser guide but you must still draw a line and use a steady hand. It's also useless outdoors in bright sunlight.

A spindle lock keeps the blade from spinning while you change blades. A blade brake stops the blade quickly when you release the trigger. The dust chute directs sawdust away so you can see what you're doing. A long power cord (9 or 10 feet) often makes an extension cord unnecessary or helps keep the extension-cord connection away from your work.

HOW TO CHOOSE

Decide the kind of work you'll do. For occasional light cutting, most any saw is fine. For heavy use or for cutting hard or thick wood, choose a saw with speed and power, such as the top-rated models. Speed also affects safety; you're more likely to push a slow saw, dulling the blade quickly and overheating the motor as well as raising the risk of jamming and kickback.

Try it out. Look for easy blade changes and adjustments for depth and angle, good balance, a comfortable handle, and a handy on/off switch. Also look for easily accessible motor brushes, a heavy-duty base, and rugged hardware for blade-depth and cutting-angle-adjustments.

Check the blade. Most saws now have carbide-tipped blades, which cut quicker and last longer than steel blades. (You can retrofit them to older saws.) Match the number of teeth with the material you want to cut; blades for plywood, say, have more teeth than those for rough cutting.

Safety counts. All saws are loud enough to warrant hearing protection. They also kick up lots of chips and dust, so wear a mask and safety glasses or goggles.