Published by The Taunton Press, Connecticut, USA.
in The Australian Woodworker Issue 72
There are still those who associate wood dust problems only with large-scale industrial operations.
However, many amateurs work in garages or sheds that serve multiple purposes, as a laundry or storage for the kid's bikes, cars, garden tools, old furniture and boxes of clothes. The presence of prodigious amounts of dust in such areas becomes an obvious problem.
Then there's the well publicised health risks of fine wood dust as well as the fire and safety hazards of leaving wood shavings and dust lying about.
Yet keeping all this dust under control is easier than some would think.
Woodshop Dust Control, by Sandor Nagyszalanczy, looks at the whole question of dust control, starting with very specific health hazards, and moving on through the range of solutions - from modifying work practices to various forms of mechanical dust extraction.
In the first chapter, Nagyszalanczy discusses the type and volume of dust produced by various machining operations, pinpoints practices that can lead to an increased fire hazard, and the risk of an explosion in the presence of high dust concentrations. He looks at various alternatives for dust disposal, including its use, after appropriate ageing, as a garden fertiliser.
Chapter Two presents a brief overview of dust control methods, from the use of face masks and respirator helmets, to complete air filtration devices and portable dust extraction machines. The advantages and disadvantages of the various methods of control are condensed and highlighted in a straight-forward chart.
A host of 'good-housekeeping' methods are discussed at length. Identified are some key common-sense methods for keeping dust under control, such as using a special foot broom device - fashioned from a few brushes and a bit of ply - to keep dust from shoes, out of the house.
Chapters Three to Six form the bulk of the book, examining the major forms of mechanical dust extraction at length. Chapter Three looks at respiratory protection devices that prevent dust from entering the throat and Iungs by covering the nose and mouth, or the whole face. Such devices include disposable filter masks, filter-cartridge face masks and the portable air purifying helmets. The book looks closely at the subject of filter cartridges and their capabilities, including the appropriate uses of organic vapor cartridges in the workshop.
Chapter Four covers shop ventilation in general and looks at the use of Air Filtration Devices (AFD). These boxed extractors are hung from the ceiling in strategic locations in the shop, and are designed to circulate and filter the airborne dust using a two stage process.
This chapter includes formulas for calculating the required extraction capacity of an AFD for your size shop, layout of the system to maximise its benefits, and even how to build your own AFD.
Chapter Five looks at the canister-type vacuums, sometimes generically referred to as shop vacs. The most interesting part of this section is the various jigs and fixtures for making the shop vac more versatile.
Chapter Five covers portable dust extractors, mainly the two bag variety with 100mm hose diameters. They are portable, powered by induction motors and larger fans, and ideally suited to extracting dust and large debris from single stationary machines.
Chapter Six discusses the basics of central dust extraction systems, focusing on the principles of single and two stage collection. It describes methods for calculating the requirements of a particular shop, based on the area and number of machines, and looks at the specific advantages of cyclone systems for pre-separation. Various alternatives such as home made canisters and drop boxes and the different filter technologies are discussed.
Chapter Seven deals with setting up an extraction system. The design process involves setting out a shop-layout, and defining the space and placement of machines covered by the central extraction system. The placement of the perimeter and diagonal main ducting should maximise the proximity of each machine to the duct and minimise junctions and the overall length of the ductwork.
This chapter also covers calculating ducting diameters to maintain maximum force of suction through the system as a whole, contains a chart of various machines and their suction requirements at the ducting inlet, and shows how to estimate overall power needs.
Chapter Eight deals with the 'meat and potatoes' of actually installing the ducting, showing how to cut and join the various sections. Included are the side issues such as home made shut-off gates, the grounding of duct work to reduce the risk of electrostatic shock (and potential dust explosions or fires), testing and tuning formulas for air velocity and pressure in the ducting system, and alternative methods of controlling the whole system electronically.
Chapter Nine covers accessories and some innovative designs such as a dust box for a lathe, a hood for a router and a dedicated sanding table that captures sanding dust through the perforations in its top. It is hard to see how this book might cover the subject any more thoroughly.
It should be considered a small investment for anyone contemplating their own requirements - big or small - and offers an objective view of the various alternatives available.
Photos: Black & White
Units of Measurement: Imperial
Problem of Dust in the Woodshop
for Controlling Dust
Ventilation and Air Filtration
Dust Collection Devices
a Central Collection System
a Central Collection System
Hoods and Other Devices