When we think of urban agriculture, rarely do we think of growing mushrooms! The steps on how to go about becoming an urban mushroom grower will be shared on this broadcast. Wes was Head Gardener at City Farmer for over ten years. He was loved by everyone and will be sorely missed by all of us who worked with him at the Vancouver Compost Demonstration Garden.
On his retirement from City Farmer in , this song was written about him. Application of pesticides, including insecticides, herbicides, and fungicides, will be restricted. Certain conditions will need to be met before pesticides will be permitted provided they are listed in Schedule A to the by-law. Perhaps the most important sites, from City Farmer's perspective, are people's home gardens.
Back lanes are useful for studying urban agriculture. They display the private back yards of homes, making it is easy to see what gardeners are growing. Posted January 24, It described in everyday language how the authors grew all their own food right in the middle of the city of Berkeley. This inspiring book led us on an exploration of urban food production, which continues today, twenty-five years later.
Posted January 25, Vancouver's Worm Program Written-up in Der Spiegel Magazine "Der Spiegel magazine published a story about Vancouver's worm composting program in their well-read magazine on page of issue No. Their circulation is around 1. Their on-line site publishes roughly 60 stories a month, and has on average 1.
This is wonderful coverage and shows the world our City's commitment to a healthier environment. Posted September 14, You will need QuickTime and the On2 codec installed to view the tour. This software is free and can be downloaded once you click on the link. If your QuickTime software and browser won't play the tour, go to this site and download the On2 QuickTime plugin.
On2 Plugin Updated September 13, News Flash March 1, See City Farmer's country count. Almost 5 million hits were recorded on our site during the year ! How to find information on our site. Our web site includes both local Vancouver City Farmer stories and urban agriculture information from around the globe. The "Recent Pages" link just below is updated almost daily. That's where you'll find all the latest stories.
Don't miss it! After 28 years digging in the fields of Urban Agriculture, we want to share with you what we have learned. The Web makes it possible for us to reach a much larger audience than we were reaching before the arrival of on-line publications. Our non-profit society promotes urban food production and environmental conservation from a small office in downtown Vancouver, British Columbia and from our demonstration food garden in nearby Kitsilano, a residential neighbourhood.
Posted May 2, Urban Agriculture is a new and growing field that is not completely defined yet even by those closest to it.
It concerns itself with all manner of subjects from rooftop gardens, to composting toilets, to air pollution and community development. It encompasses mental and physical health, entertainment, building codes, rats, fruit trees, herbs, recipes and much more. Our Office wants you to know about some of the issues we deal with from day to day. There are very few offices in the world that have our experience serving city farmers all year round or have done so for as many years as we have.
These pages will grow as we select the latest breaking information that comes to us, as we review our large library of resources for useful documents to put on-line, and as we hook you up with other Urban Agriculture Web sites that most certainly will emerge. Urban Agriculture Notes is written for those who want to start up their own "Office of Urban Agriculture", for those who have already done so, and for gardeners who are curious about what we refer to as political horticulture.
City Farmer's Urban Agriculture Survey Please help us learn more about your involvement in city farming by filling out this short survey form. Retrieved February 25, I believe I forgot to tell you one Anecdote: When I first came to this House it was late in the Afternoon, and I had ridden 35 miles at least.
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Huston, "is it lawful for a weary Traveller to refresh himself with a Dish of Tea provided it has been honestly smuggled or paid no Duties? I can't make Tea, but I'll make you Coffee. Tea must be universally renounced. I must be weaned, and the sooner, the better. General Riedesel's Adventures". Albany: Joel Munsell. She then became more gentle, and offered me bread and milk. I made tea for ourselves. The woman eyed us longingly, for the Americans love it very much; but they had resolved to drink it no longer, as the famous duty on the tea had occasioned the war.
At Google Books. NCA News. National Coffee Association. The coffee book: anatomy of an industry from crop to the last drop. The New Press. Nelson's Sailors. Osprey Publishing. Basic Books. June American University. Archived from the original on May 11, Retrieved February 18, London: International Coffee Organization. Archived from the original on March 24, Retrieved January 4, Berthaud, J. Plant Genet Resources Newsletter. Purdue University. Archived from the original on May 7, Core Collections of Plant Genetic Resources.
Management of Horticultural Crops: Vol. New India Publishing. February 16, National Geographic. Retrieved September 25, In Uhlig, Siegbert ed. Encyclopaedia Aethiopica. Wiesbaden: Harrassowitz. Zed Books. New York: McGraw-Hill. Coffee pests, diseases and their management. Oxford Research Encyclopedia. Retrieved September 20, New York: St. Martin's Griffin. Reading, MA: Aris Books. Costa Rican natural history. Chicago: University of Chicago Press.
Archived from the original on September 22, Retrieved January 5, October Archived from the original PDF on August 15, Retrieved January 18, Retrieved February 19, Smithsonian Institution. Archived from the original on October 25, Retrieved January 8, Arbor Day Foundation. Scientific American. MES thesis. The Evergreen State College. New Scientist. The Rodale book of composting. Emmaus, PA: Rodale Press. Retrieved October 26, May 24, The Guardian. Retrieved May 27, Bloomberg Businessweek. Retrieved March 1, Food Research International. The Richest, Valnet Property.
Retrieved November 25, The Economist. Washington State University. Archived from the original on July 1, Retrieved July 18, Bellissimo Info Group. Scribblers Coffee. Retrieved April 2, Permit Handbook. May 15, Archived from the original on March 3, Archived from the original on October 19, Consumer Reports. May Storing coffee. Retrieved February 27, Food Network. Archived from the original on April 16, Popular Science. Food Quality and Preference. Mountain City Coffee Roasters. Archived from the original on May 10, The Coffee FAQ.
All about Coffee 2nd ed. Gale Research. Retrieved January 12, Firefly Books. Retrieved December 9, American Journal of Epidemiology. The Great Coffee Book. Ten Speed Press. Black Enterprise. Retrieved October 29, All About Beer. Retrieved November 24, Retrieved May 25, CNN Money. Cable news network. December 6, Commodities Report. The Wall Street Journal.
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March 21, Medium-term prospects for agricultural commodities. Projections to the year Food and Agriculture Organization of the United Nations. Global output is expected to reach 7. Retrieved January 13, The Seattle Times. Retrieved May 3, The Huffington Post. Retrieved December 10, Retrieved April 3, Bloomberg News. Archived from the original on April 27, Archived from the original on July 10, So many people who have written about coffee have gotten it wrong. Coffee is not the second most valuable primary commodity in world trade, as is often stated. Coffee is the second most valuable commodity exported by developing countries.
New Straits Times Online. September 29, Archived from the original on October 18, Global Saskatoon. Retrieved November 4, International Coffee Organization.
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June 1, Retrieved January 27, The British Coffee Association. January 5, A review". Scandinavian Journal of Gastroenterology. The effect of coffee on resolution of ileus following abdominal surgery: A systematic review and meta-analysis of randomised controlled trials". Clinical Nutrition : —4. Scientific Reports. New England Journal of Medicine. British Journal of Nutrition. Public Health Nutrition. Annals of Internal Medicine. International Journal of Cardiology. Circulation: Heart Failure. Coronary Artery Disease. The American Journal of Clinical Nutrition. National Health Service, UK.
December 19, Advances in Psychiatric Treatment. Expert Review of Neurotherapeutics. Food and Chemical Toxicology. Psychological Medicine. May 28, Current Addiction Reports. January 1, Molecular Nutrition and Food Research. J Nutr Health Aging. Japanese Journal of Clinical Oncology. European Journal of Cancer Prevention. Lung Cancer. BMC Cancer. Life Sciences. Acta Medica Croatica. Studies Find Some Benefits". The New York Times.
Retrieved January 26, E ; Rice-Evans, Catherine Free Radical Biology and Medicine. EFSA Journal. Journal of the American Dietetic Association. Mayo Clinic. Retrieved July 22, Retrieved January 6, Retrieved December 8, January 15, Variations of the caffeine content in coffee beverages. Roasty Coffee. July 10, Retrieved August 5, Prima Coffee. Retrieved October 10, A History of the World in Six Glasses. Atlantic Books. Retrieved February 13, Oxford Dictionary of National Biography.
Bezirk Erfurt , p. Massachusetts Travel Journal. Peet, 87, Dies; Leader of a Coffee Revolution". New York Times.
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Company profile from Hoover's. Retrieved October 9, Asia Today. February 5, Retrieved June 24, Cafe Culture. November 29, Classification of Sizes It may be advisable, under this heading, to mention the classification under which, according to their sizes, various pieces of sawn or converted timber fall. The terms are generally used very loosely. A strip also refers to the pieces used in the seasoning of timber for separating the boards to facilitate drying.
Sometimes called stickers. Scantlings: Sawn to dimensions of up to 6 X 4 in. Baulk: Deal: Applied generally to European softwoods between 2 in. Hewn timber: Timber shaped by axe or adze roughly to a given size. In North America the word "lumber" corresponds to the word "timber" as used in Australia. In the former countries, "timber" is defined as sawn material whose least dimension is 5 in. Superficial Feet The unit of measurement of timber as used in Australia is the superficial foot. It is the equivalent of one square foot in area, 1 inch in thickness.
A superficial foot is usually spoken of as a "super foot" and written in the abbreviated form, sup. Measurements of sawn timber with certain modifications and exceptions mentioned later and of the contents of logs are expressed in terms of superficial feet. Computations involving costs, statistics, etc. In North America the corresponding term for "superficial foot" is "board foot" and computations in that continent are usually based "per 1, board feet", often abbreviated to per mb.
In most British countries the superficial foot is the standard unit of timber measurement, though bases of computations vary e. The method of finding the measurement of a sawn board in superficial feet is to multiply together width and thickness in inches and the length in feet, and to divide the result by Thus the measurement in superficial feet of In this example the sum of the lengths in feet i. Following is an example of a specification of a variety of sawn sizes together with the lineal and superficial footage of each size: Lineal ft.
As previously stated, the basis for costing, etc. A modified procedure is adopted for thicknesses of less than one inch. In such cases the measurement is based solely on the area in square feet of the board faces, the particular stock being identified, and its price determined, by reference to the thickness. The measurement of such stock is referred to as superficial face measurement, abbreviated to "sup. Lineal Measurement This form of measurement refers to the sum of the lengths of boards or mouldings having the same dimension.
It is also known as running measurement. Abbreviations for lineal feet and for running feet are written "lin. Round timber, such as piles and poles, and also hewn girders, are usually sold on a basis of lineal measurement. Lineal measurement applies also to mouldings and dressed timber of small dimension. In such cases the basis for costing, etc. Measurement of Dressed Timber Methods of computing the measurements of dressed timber differ among some of the Australian states. For example, in Victoria and South Australia, the practice is to refer to quantitative measurements of all moulded timber including floorings, linings and weatherboards, in terms of lineal feet.
In New South Wales and some other states the practice is to compute tongued and grooved items and heavier moulded sections in terms of the superficial measurement of the nominal size of the section. Nominal size refers to the original intended dimensions of the section before machining e.
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Finished size refers to the dimensions i. Plywood measurement is based on surface area in square feet super face measurement. Without examining the origin of this awkward and inconvenient figure, it is sufficient to state that it represents the equivalent of 1, superficial feet, or cubic feet. The Cubic Foot In some British countries e. British North Borneo timber measurement as applied to both logs and sawn timber is calculated on the basis of the cubic foot abbreviated "cu. The 7th British Forestry Conference passed a resolution that all British Commonwealth countries should use the cubic foot in referring to volumes of logs.
To convert cubic feet into superficial feet or vice versa it is merely necessary to multiply or divide respectively by Example: 1 cu. Tonnage Measurement This measurement is used in Malaya, Sarawak and several other countries and applies to both logs and sawn timber. The ton is assumed to consist of 50 cubic feet, or super feet. It is important not to confuse this measurement, as used by the timber industries in the countries concerned, with the shipping ton as applied to timber. This latter is usually calculated at 40 cubic feet per ton.
The Load The unit of super feet is also known as a load and is in common use in the United Kingdom when applied to timbers of other than European origin. The load unit is also used extensively in Western Australia. It is important to know that the load unit, when applied to round timber, i.
The Metric System The unit of timber measurement under the metric system is the "cubic metre" abbreviated "M 3 ". It is the equivalent of For practical purposes, in converting metres to feet, it is often convenient to regard 4 metres as the equivalent of 13 feet, and vice versa. The "cord" is a unit of measurement equalling cubic feet true measure. The "cunit" is a unit of measurement usually applied to round-wood for pulp manufacture equalling cubic feet true measure. Tables for reckoning the contents of logs are not included in this handbook owing to the amount of space that would be required for effective tabulation.
Such tables Brereton, Hoppus, etc. The Practical Lumberman. Seattle, Washington, U. British Columbia Lumber Manufacturers' Association. Vancouver, B. Bruce, D. Forest Mensuration. New York, McGrawHill, Commonwealth of Australia. Lachowsky, M. The Plywood Calculator. Ernest Benn Ltd. Laver, C. Principles of Log Measurement. The Lumberman.
Log Scaling. Portland, Oregon, U. Lightning Timber Calculator Hoppus Tables. Cole, Melbourne, Vic. Queensland Forest Service, Wilson, S. Decimal Hoppus Tables, showing the solid contents of round timber in Hoppus feet and decimals. London, Scientific Computing Service. The proportion of marketable timber recoverable from a given quantity of logs is ever variable and depends upon a number of factors. Principal among these are the class and quality of logs to be sawn, the specification to which the output is required to conform, and the judgement of the sawyers. The rate of production is also influenced by the above factors, but will also depend upon the design of the mill, the saws used, sufficiency of power, and various considerations of a mechanical nature.
Not the least important factor, however, in the conversion of logs to sawn timber is the full use of experienced judgement and of care in sawing and selection. Although these latter considerations may, and usually do, slow down production, it invariably happens that careful attention in the initial stages of timber manufacture is noticeably reflected in a higher quality product, and in lower costs in the subsequent processes of seasoning, re-manufacturing, machining, and general yard handling.
Sawmill efficiency is not, therefore, to be measured only in terms of volume of production per man hour, but rather in timber value per man hour. Mill design and methods of sawing in Australia are largely governed by the class of timber to be sawn, i. These latter terms are used here in their broad meaning as applying on the one hand to the more soft textured timbers such as pine, coachwood, maple and similar cabinet timbers, and on the other to the great family of eucalypts and similar timbers of marked density.
There are exceptions in both cases but, generally speaking, mill design and methods of conversion depend upon the class of logs to be sawn and are further modified by the average size of logs available. In sawing logs into boards at the mill, there are several distinct and fairly standardised methods of handling the log. The simplest method is that of ripping the log into boards by means of a series of parallel saw cuts without any turning of the logs.
This method is known as "live sawing" or "sawing through and through". Other methods involve a turning of the log as sawing proceeds so that the cuts are made in different planes. These methods are known collectively as "sawing around". Live Sawing Live sawing is illustrated in Fig. This system is practised in the larger Australian radiata pine mills, in most of which gangsaws are used in converting plantation grown logs.
Live sawing is also used for cutting cypress pine logs in New South Wales and Queensland, where the logs are passed over the usual breast-bench after a preliminary "spotting" or facing of one side on a breaking down bench. Apart from these two instances, live sawing is not regularly used in Australia, though it is the usual method of sawing in Europe, particularly in the Baltic countries, and is also used to some extent in America for small logs.
The live sawing method is well suited to mass production, and gives the highest recovery from the log, at lowest milling cost. The logs are simply fed into the saws, and the boards emerge from them in a constant stream without any turning of the logs or returning of any material for re-cutting.
Production is rapid and the procedure is standardised, requiring no high degree of skill. Operating costs are therefore held at a minimum. The method lacks elasticity however, and is not suited to the production of timber of varied sizes and qualities. It is not possible, with live sawing, to segregate clear from knotty timber, nor can defective logs be handled without heavy loss. Furthermore, due to the mixed grain occurring in most of the boards, live sawing can be practised successfully only with light and easily seasoned timbers.
Otherwise, heavy seasoning degrade is encountered in the form of cupping, warping and unequal shrinkage. Figure 2. Live sawing is therefore restricted in its practice to the handling of the lighter species where logs of uniform size, of good form, and free from internal defects, are to be milled to produce standardised lines of no great range in quality.
Where refractory timbers are to be treated, where virgin forests have produced trees of a large range of size and quality, perhaps over-mature and containing various internal defects, and where a sharp price differentiation exists between various grades, making it necessary to separate material of different quality in the cutting, live sawing gives way to methods based on sawing around.
Sawing Around The various methods of sawing around all aim to separate material of different quality such as sapwood and truewood, clear portions and knotty portions, or sound timber and faulty stock, by means of breaking down, turning, or altering the position of the log during the sawing, so that the boards are cut in different planes. There are two main methods, each with a large number of minor modifications to suit different species, different sizes of logs and different market demands.
These two methods are "back-sawing" and "quarter-sawing". Back-sawing aims at the production principally of back-sawn boards, i. It will be obvious from the diagram that while back-sawing and quarter-sawing both involve the cutting of the log in different planes, the plane used for quarter-sawing in any portion of the log lies at right angles to that used for back-sawing the same portion of the log. Each method has its special advantages which will be discussed in turn.
The method is illustrated in Fig. As a general sawing method, back-sawing has a number of points in its favour. The method is highly flexible and is well suited to securing highgrade timber from faulty and varied logs. Compared with quarter-sawing, back-sawing has the following advantages: 1. Back-sawing will in general give a higher recovery from the log, and a greater output per hour from the same run of logs, while the method is somewhat simpler and more easily grasped by the average sawyer.
Figure 3. For large over-mature or defective logs, a dozy, shaky, or knotty interior may be separated from an outer area of clear truewood, and that again from a layer of sapwood, more effectively and with less loss by back-sawing. Knots, if present, show in cross section in simple form, rather than as spike knots across the face, while defects such as ring shakes and gum or resin pockets may be completely cut out in one back-sawn board instead of affecting a number of adjacent quarter-sawn boards.
In many hardwoods, particularly in butt logs, there is considerable taper in the diameter of the defective "heart" surrounding the pith and it is profitable to saw parallel to the log surface leaving just enough sound wood to contain the faulty "boxed" heart for its removal in one piece from the saw bench to the dump. A greater proportion of wide boards may be obtained by back-sawing than is possible by quarter-sawing logs of given sizes.
Back-sawn boards will ordinarily season more rapidly than quarter-sawn boards, and with less shrinkage in thickness. With timbers such as Douglas fir and several of the pines, whose figure is formed by differences in texture of the two parts of the growth ring, a backsawn face will reveal the figure, while a quarter-sawn face will be relatively characterless.
A similar case can be made for back-sawing timbers with soft tissue wood parenchyma in concentric bands in the log, such as the tulip. Figure 4. In a sawmill equipped with a log carriage type breaking-down unit, back-sawn boards are produced as illustrated. Figure 5. Back-sawing as practised in Australian sawmills with a breaking-down bench and breast-bench. In many timbers, nails or spikes may be successfully driven into the back-sawn face, whereas driving into a quarter-sawn face would result in splitting.
This applies particularly to eucalypt timbers used for case making, and also is of the greatest importance for sleepers and bridge decking. On the other hand, there are cases where quarter-sawing possesses special advantages outweighing these features and justifying its use as a regular sawing procedure. These advantages are discussed in the following section. For many decorative timbers, the figure is caused either by the effect of large conspicuous rays on a contrasting background, as in oak and in the sheoaks and silky oaks, or by the stripe or ribbon effect caused by an interlocked grain, as in Queensland walnut and maple.
In all such timbers, the figure is revealed only on the face of quarter-sawn boards, the back-sawn faces being plain and devoid of any distinctive features. Quarter-sawing is, therefore, regularly practised with such timbers. In the case of coarse-textured timbers, flooring boards and joinery stock are frequently quarter-sawn to produce "edge grain" material of higher value than "flat grain" back-sawn material of similar quality because it shrinks less and wears much better.
Edge grain flooring, for instance, will wear evenly and smoothly where back-sawn boards would sliver up and shell off. This applies particularly to Douglas fir, but is also important with many eucalypt species where used for factory flooring, decking, etc. These gum veins show on a back-sawn face as broad splashes, which are a serious detriment to finished boards. On a quartersawn face, however, the gum veins show as narrow lines of far less serious character.
Quarter-sawn timber, though it dries more slowly, is markedly less likely to develop defects in seasoning than is back-sawn timber, being less prone to cupping, warping, and checking. It also shrinks less in width, and so may give less trouble due to hygroscopic "working" in use. With refractory timbers, such as the Australian eucalypts, this becomes a matter of great importance, because the saving in avoidance of seasoning losses is frequently more than sufficient to offset the disadvantages of slightly lower recovery, and somewhat slower production obtained when quarter-sawing, as compared to back-sawing.
Another point of considerable importance is that quarter-sawn eucalypt timber, even though badly collapsed, can be successfully reconditioned with little chance of developing injury, but back-sawn timber is so prone to open checks in redrying that, for many species, the reconditioning of back-sawn timber is definitely not economical. It is principally from the seasoning aspect, as well as the matter of the gum veins mentioned above, that quarter-sawing has been adopted in the Victorian and Tasmanian mills.
So successful has it proved that the Division of Forest Products recommends its adoption in other states wherever finish timber is being cut from the native eucalypt species. In New South Wales and Queensland, in mills where the principal sizes in finished hardwoods are in flooring and weatherboard dimension, a high degree of satisfaction must result where these methods are employed. This practice of quarter-sawing, together with the development about the same time of the processes of kiln seasoning and reconditioning, has been of the greatest assistance in the development of the finished hardwood trade of Victoria and Tasmania.
Where in previous times the "ash" timbers were considered suitable only for scantling and rough timber, and were considered most refractory to season and unsatisfactory in service, they are now in keen demand for all forms of finish timber, as flooring, lining, weatherboards, joinery, and practically every other building line, besides forming the bulk of all timber used in motor body building, furniture making, and other wood-using industries.
In the mills, study of the peculiarities of the hardwood timbers has evolved a method of breaking-down and benching which results in a high recovery of quarter-sawn finishing material by a simple and straight-forward procedure, so that earlier criticism in Australia that quarter-sawing gave an unduly low recovery and low output per hour, is now refuted. Under the technique in use, both the recovery and the output are only slightly inferior to those obtained when back-sawing similar logs, while the saving of material from seasoning degrade greatly overbalances these two factors.
Method of Quarter-sawing 1. Accuracy of Quartering Required. Where quarter-sawing is practised with a view to developing the figure of decorative timbers, it is important to have For such timbers, specifications for quarter-sawn material usually demand that the growth rings shall show an angle of not less than 80 degrees to the face of the boards. In other words, the boards may not vary more than 10 degrees either way from the exact angle of the rays if they are to fulfil the specification. Such timber is referred to as fully quarter-sawn. In cases where quarter-sawing is practised, as it is with the "ash" eucalypts, principally to avoid seasoning losses, there is no need for such a close adherence to the exact plane of the rays, and the quarter-sawing is done, as with back-sawing, in four planes only.
The specification to be fulfilled in Tasmania and Victoria defines quartersawn timber as timber in which the angle of the growth rings to the face is not less than 45 degrees. In such circumstances, a straight-forward technique can be used which will allow comparatively rapid cutting and high volume recovery. As will be seen from the diagrams illustrating the method, the material produced ranges from fully quarter-sawn material from the central portions of all the main flitches down to boards falling just within the specified limit and cut from the outer portions of the wings.
On an average, roughly two-thirds of the output will show an angle of 70 degrees or more between the plane of the growth rings and the face, the remainder showing an angle of 45 to 70 degrees. Processes Involved. In sawing logs for board production under Australian conditions, there are three steps or processes which must be distinguished to facilitate a clear understanding of the explanations and diagrams to follow. The first step consists of breaking-down the log into a number of flitches which can be handled by the bench crew.
Cuts made in this initial breaking-down are termed primary preparation cuts. The second step is that of "sizing-up" and consists of re-cutting the flitches into pieces squared and cut to size ready for the final stage. These cuts made in sizing-up are termed secondary preparation cuts. The final stage is the "ripping-off" in which the sized pieces are passed through the saw again and again, a board being ripped off from the gauge side of the saw with every cut, until the piece is completely sawn up.
The first two steps are both preparatory steps, producing no boards from any cuts of the saw. It is only when the third stage is reached that the desired final products are obtained. It is necessary, however, to make the distinction drawn above, between the primary and the secondary preparation cuts, as in usual practice they are made on different benches. Mill Equipment. In most hardwood mills, the equipment consists of two units, the breaking-down unit and the breast-bench.
The breaking-down units used are the twin circular saw with either the simple table top platform, or with a carriage equipped with hand-operated knees or dogs and the reciprocating sash frame with vertical saws. In most mills, only the primary preparation cuts are made on the breakingdown unit, leaving the secondary cuts, together with the ripping-off, to be done on the breast-bench.
This procedure is always followed where the breastbench is fully manned and equipped with power-driven rollers. There are some This entails a scale and setworks on the carriage to enable the sizing-up to be done accurately. In either case, the technique of breakingdown and sizing-up is the same. Primary Cuts. In making the primary cuts on the breaking-down unit, the aim is mainly to reduce the log to flitches of a size and weight manageable by the breast-bench crew, at the same time segregating high quality stock from low quality stock as well as can be judged by what is seen of the log.
The flitches so made are not cut to any definite size, as the sizing for width can only be done after the flitch is turned down. This is the chief point of difference from breaking-down for back-sawing, where the flitches are cut to a measured size to yield boards of a definite width. The fact that the flitches are not cut to any definite size makes it necessary to guard against avoidable waste due to inaccurate alignment on the table top or carriage. Though the flitches are not cut to any definite size, there is a very marked tendency to follow along a standardised plan in the breaking-down, so that logs of certain diameters are almost always broken down in the same manner.
The two factors influencing this procedure are the size and weight of the flitches which must be handled by the bench crew, and the clearances available in the saw frame. The usual twin circular saw has a vertical clearance between platform deck and upper saw collar of about 4 feet 6 inches, and a horizontal clearance between the saw and the frame of about 1 foot 6 inches. This will handle logs up to about 5 feet diameter. Any logs larger than this would require blasting or trimming with the axe.
The usual sash frame vertical unit has a clearance of 6 feet 6 inches to 7 feet, and will take logs up to this diameter at the large end. The general method of breaking-down with the twin circular saw unit is shown for logs of a range of sizes, including cases of defective heart, in Fig. The same procedure for large logs at mills equipped with a vertical sash frame breaking-down unit is illustrated in Fig. Secondary Cuts. The secondary preparation cuts, made usually on the breast-bench, constitute the most important stage in the sawing process, since the whole essence of quarter-sawing lies in the way in which these cuts are made.
The procedure followed is illustrated in detail below for flitches produced from the logs shown in Figs. In all cases, it is assumed that a right hand bench is used. The first case is that of the small log up to inch diameter, which has been halved on the breaking-down saw. Log A in Fig. The first two cuts are put through by eye, so as to give a balance between the central portion and the two rings, with due regard to the position of large unsound knots, dry sides, or other defects apparent on the flitch.
These are cuts a and b in Fig. The central portion is then turned slab side to the saw, and cut c is made removing the slab, which will be cut later to give a batten, paling, or small scantling. The gauge is then used for the first time, to Figure 7. Method of breaking-down large logs with a vertical sash frame breakingdown saw.
For a log approximately inch diameter. Cut d is then made with the outer or slab face of the flitch against the fence or face of the gauge. This completes the sizing-up of the first piece. The remainder, or off cut from cut d , is usually hearty or otherwise defective. It may be completely discarded or may be ripped to give a batten or small scantling piece, depending on size and quality.
As cuts a and b are not put through to measure, the last cut in ripping-off will always leave a face cut. Skilful benchers are able to hold the loss in face cuts to a low volume simply by eye. The central piece disposed of, the two wing portions remain to be treated. These will be cut in a plane at right angles to that used for the central portion.
Taking the right hand wing first, it is turned 90 degrees so that it rests on the face of cut a. Cuts are then made one inch apart, giving four wide boards until point e is reached. Continued cutting in this plane would give boards. A 4-inch width is therefore obtained with cut f , and the piece turned again to give the two 4-inch boards shown, with further cutting to obtain a 2-inch x 2-inch square from the last piece of the wing. With the left-hand wing, cut g is put through by gauging from the face of cut b , giving the 4-inch width in one cut.
The piece is then turned down on to the face of cut g and the boards ripped-off until the cutting runs out. In dealing with larger logs, the benches will have flitches of somewhat different character to handle. The next example log C in Fig. The cutting for this log is shown in Fig. The first Hitch differs from the half log in the previous illustration Fig. After making the first two cuts, therefore, the sawyer may take his width from the face of the flitch towards the slab, and put in cut c to measure, rather than putting in cut c at random and then gauging back to a fourth cut.
Flitches 2 and 4 are essentially similar to flitch 1, except that one wing is missing, and are treated along similar lines. The diagram for these two flitches is self-explanatory. Flitch 3 requires special treatment as it contains the heart. Cut a is put through first by eye, dividing the flitch into two parts. Cut b then gives the width for the first or inner sized piece, leaving the "hearty" portion to be treated later. The outer portion may then be sized for width immediately by using a pin in a slotted plate on the left-hand side of the saw, a very common practice, or the piece is turned over degrees, and the width taken from the gauge.
It is not practicable in a flitch of this size to put in the outer cut first and then work inward, due to the cumbrous nature of the flitch and the lack of clearance on the off-side of the bench, so that the procedure shown in. With these three cuts made, two pieces are sized ready for ripping-off. The slab offcut will then be cut for batten or paling residuals, while the central, or "hearty" portion to the left of cut b may yield battens, squares or scantlings. The secondary cuts required for logs D and E Fig. Slightly different treatment is met with in larger logs where the primary cutting involves turning the log more than once on the breaking-down platform.
The treatment of log F, 46 to 50 inches in diameter, is therefore detailed in Fig. This may be taken to typify the treatment of all large logs. It is believed that the data given in Figs. Bryant, R. Lumber: Its Manufacture and Distribution. Wright, G. Division of Forest Products. Reprint No. In addition, several excellent books treat this subject very fully. Circular Saws In Australia the circular saw is often used as the headsaw for breakingdown logs. It is used singly, or, for deeper cutting, in the form of twin saws, i. Either a simple table top platform or a carriage with setworks can be used for passing the log through the saw.
The single saw is limited to cutting relatively small logs and the twin saw, and, though capable of deeper cuts, is limited by the distance between the arbors of the two saws. A vertical frame saw, with one or two blades, is often used in conjunction with these other saws to make those primary cuts with which, by reason of their limitation, circular saws are unable to cope.
In hardwood mills the circular headsaw is usually confined to the breakingdown process, the flitches resulting therefrom passing on to the breast-bench. In most softwood mills the log is more or less converted at the headsaw and only the edging and docking carried out by the subsidiary saws. Advantages of the circular headsaw are: 1. Relatively low cost of equipment. Relatively low cost of saws and of their maintenance compared with handsaws. Simplicity in adjustment and operation compared with bandsaws. Less skill is required to maintain saws in order compared with bandsaws.
Circular saws will stand more rugged usage than bandsaws and are not liable to the same extent of damage when fouled by stones, metal spikes, etc. The log carriage, if installed, does not require an offset. Disadvantages: 1. Relatively wide saw kerf resulting in greater waste in cutting. Power requirements greater than other types of saw owing to the wider saw kerf and to the angle at which the teeth strike the timber. Blade friction is also greater. Circular saws are unsuitable as a rule for deep cutting or the sawing of wide boards. Vertical Frame Saw This machine is equipped with a reciprocating vertical frame in which are mounted one or two saws.
The logs are broken down into two or more sections which are then transferred to the breast-bench. The object of this type of frame saw distinct from the sash gang is to reduce logs to sections which can be handled satisfactorily by the other saws in the mill. Sometimes it is installed as the only headsaw in the mill; in other cases it is used as an adjunct to a circular breaking-down saw as mentioned under the previous heading. Advantages of the sash frame saw are: 1. Low initial cost. Simplicity of operation. Will stand very rugged usage. Capacity for sawing very large logs.
Very slow in operation. Suitable for breaking-down only. Sawing parallel to sapwood to exclude "heart" not possible with two parallel saw cuts.
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Bandsaw The bandsaw, used as a headsaw, consists of a continuous band of steel, toothed on one edge, passing over two wheels mounted one above the other. In general the diameter of the wheels determines the gauge of the saw which can be used, and, to a large extent, the size of the log which can be sawn satisfactorily.
A log carriage with setworks and offset is necessary for use with the log bandsaw. Modern log carriages with power-driven, precision-setworks and automatic dogs are now manufactured in Australia. The highest standards in construction and performance in breaking-down units are attained with the bandmill. The bandsaw see Photo 2 is the fastest cutting, most economical in power and least wasteful in saw kerf among the sawmilling machines.
Types for sawing logs are built generally with wheels between 6 and feet diameter, their capabilities varying to some extent with different makers, but approximately as shown in Table In Australia band headsaws are confined mostly to the cutting of softwoods and are therefore located in regions where indigenous softwoods are available, such as in north Queensland, or in those cities through which softwood logs are imported from overseas.
Although experience has shown that handsaws can be used quite satisfactorily in cutting Australian hardwoods, they have, in the main, proved unpopular for this class of work. Band headsaws are designed for a relatively high output and in Australia most installations of this type are employed in more or less fully converting the log and are not confined solely to breaking-down. Australian forests for the most part carry a relatively low footage per acre, necessitating a large number of comparatively small mills; the volume of logs available does not, in most cases, warrant installation of handsaws.
Log carriages of conventional pattern, equipped with either hand or power sctworks, are used in conjunction with both band and twin circular headsaws. Multisaw edgers or power-fed breast-benches are used behind the bandsaw for edging purposes and for separating heart defects, whilst another smaller saw is usually employed in dealing with the offcuts so made.
Advantages of the band headsaw are: 1. Saw kerf can be reduced to almost half that of a circular saw used for the same purpose. Higher output than other headsaws is possible owing to faster sawing speeds. Deeper cutting is possible with the larger type of bandsaw than with other saws. Less power is required owing to the finer gauges of saw used, and to the lesser friction of the blade.
High initial cost of equipment. Relatively high cost of saws. Greater skill is required in adjusting and operating the equipment, and in the maintenance of saws. Will not stand up to rough work to the same extent as circular saws. Gangsaw The machine generally known as the Scandinavian gangsaw consists of a sash, fitted with a number of saw blades, operating with a reciprocal motion in a vertical frame see Photos 4 and 5. The saws are spaced to cut a predetermined thickness.
Logs are fed into the machine, one behind the other, and are sawn "alive" to this required thickness. Once in operation, this thickness cannot be altered and to this extent the machine lacks flexibility. An edger or breast-bench located behind the gangsaw edges the boards thus sawn. Gangsaws are suitable only for small, reasonably straight logs where sawing for grade is not an important consideration. In sawing this type of log, however, they are highly efficient since saw kerf can be reduced to a minimum, the sawing process is automatic and continuous, and relatively small labour costs are involved.
Gangsaws are often set up "in tandem", that is, one is placed behind and to one side of the other. The gangsaw which first receives the log is usually set up to make several cuts from the outside of the log only. The few boards thus derived go direct to the edger or flat bench for edging.