Vacuum Hardware

you run a plastic hose from your clamping fixture and connect it to the vacuum port. To prevent sawdust that gets sucked into the system from clogging the valve, some systems include a filter. Others are easily disassembled and cleaned.

Although manufacturers offer a range of systems for vacuum clamping, the vacuum venturi valve is the key component in all of them. At least one manufacturer. Quality VAKuum Products, of Concord, Massachusetts (800-547-5484), allows you to trade up from the lowest-


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The essential dcvicc here is one that will create a vacuum you can turn on and off at will. You may already have read or heard about electric vacuum pumps, which aren't dependent on an air com pressor. These devices are designed for veneer clamping rather than the type of clamping needed in router woodworking. What you need for clamping operations is a gizmo that converts a stream of compressed air into a vacuum. And isn't magic (though it sure seems that it is).

The critical component is called a vacuum vencuri valve. Some manufacturers call it a vacuum pump. Whatever it's called, it's really a chunk of aluminum (or plastic) with a little gauge stuck on it. It has three ports, two threaded for '/»-inch or 'it-inch NIT (National Pipe Thread) fittings. Inside is a venturi, which is essentially a funnel. A venturi speeds up air flow; and in this device, the air flow is abetted by the fact that the air is already under pressure, since it's coming from a compressor. It rushes through the venturi so rapidly that as it roars past the adjacent vacuum port, it sucks the air right out of the port, thus creating a vacuum. After it passes the vacuum port, the air hisses out the exhaust port. The hiss can Ik* really annoying, by the way. and most vacuum valves—but not all—incorporate a muffler.

To take advantage of the vacuum created by the valve.

Atmospheric pressure "clamps" work to clamp plate. \ \ \

f Air exits valve , Compressed air connection I

On/off valve I Exhaust

Vacuum gauge

A vacuum venturi valve is the heart of all vacuum clamping systems. The compressed air enters this valve on the left; speeds up as it passes through the venturi inside the device, pulling the air in through the connection opposite the gauge and thus creating a vacuum at that port; then whistles on out the port at right.

priced system, crediting you for the initial cost of the valve. But bear in mind that as you move up, you may need more air compressor to drive the vacuum system.

The valve must be matched to the air compressor. At a price hovering around $100, you can get a valve that will convert the 1 or 2 cubic feet per minute (cfm) of air flow produced by a '/¿-horsepower compressor into a very usable vacuum. As you get into multiple-clamp applications and a need to clamp morc-porous materials, you need a system running on 4 cfm or more. It takes a 1 '/j- to 2-horsepower compressor to generate and sustain that volume of air flow.

What happens if the vacuum system needs more air flow than the compressor produces? You don't get a very-good vacuum, meaning the holding force is reduced. It takes longer (by a matter of 2 or 3 seconds) to evacuate the air from a jig, and the system has less ability to overcome air leaks. If the mismatch between vacuum valve and air compressor is pronounced, you simply may not get enough vacuum to activate the clamp.

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Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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