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New Zealand Journal of Agriculture, Volume 96, Issue 2, 15 February 1958, Page 135

Four pieces of IJin. x -Jin. angle iron (C and L in diagram above left) can now be cut 27Jin. long and drilled with a 5/16in. hole, IJ-in. from each end. They fit on the lower portion of the legs and support the saw assembly. These cannot be placed in position until later in the construction.

Saw-spindle Assembly The first need for the saw-spindle (Z 1 in the two upper diagrams on page 137) assembly is 50in. of 2in. x Jin. flat iron (D in diagrams at upper left and at left on this page and at upper left on page 137). This should be neatly bent at right angles to give a base of lOin. and each side piece 20in. To keep this frame perfectly rigid use two pieces of flat iron l|in. x Jin. and 18in. long (E in diagram at left and upper diagram on page 137). These will require to be cut accurately to the correct angle and electric welded into position as shown in the drawing. This frame should line up perfectly when looked at from all angles.

Two lin. holes are now drilled 18gin. from the top to take the lin. pivot shaft (F in diagrams upper left and at left). It is sometimes better to drill these holes jin. and take the rest of the metal out with a round file. In this way the shaft can be fitted more accurately. When this is done the shaft can be placed in position with about equal lengths protruding from each side of the frame. Weld the shaft on to the frame from the inside. The pivot bearing is Fl in the diagram at upper left on this page.

Two pieces of 2in. x Jin. x 4in. flat iron (G in the top diagram on page 137) can - now be welded to the top of the frame, care being taken that they are in the correct position for the saw spindle to bolt on to and that the saw will be about sin. from the frame.

Two pieces of lin. x j-in. angle iron (H in the diagrams at upper left and left on this page and the upper diagram on page 137) 12in. long can now be bolted to the inside of the frame just above the pivot shaft. These are bearers for the platform (Hl in diagram at left) to take the electric motor.

The saw spindle can now be bolted on to the frame. When buying the spindle make sure that the shaft for the saw is long enough to take a set of dado cutters; also that the other end is suitable for taking a boring chuck. The spindle should have a left hand thread and is bolted on to the frame as shown in the upper diagram at right, care being taken that the shaft is in line with the pivot shaft (F) at the bottom.

Two lin. bearings and collars are now required to support the sawspindle assembly.

Rapid progress can now be made with the general assembly of the saw bench. Using four G cramps, place the 2 pieces of angle iron C (upper left diagram on page 135) in approximate position on the lower part of the wooden legs. The bearings on the pivot shaft should now be placed in position and the angle iron adjusted until the saw spindle will allow about 2Jin. of an Bin.-diameter saw to protrude above the bench table. It will be found that to do this it is generally necessary to cut away under the table to allow room for the collars holding the saw. Once the correct height has been found and the two angle pieces C have been lined up for level the holding holes in the legs can be bored.

Before removing the cramps position the bearings so that the centre of the pivot shaft is lOin. from the front edge of the legs. When iron is being marked it is sometimes best to rub chalk over the likely position and then use a sharp nail or scriber for scratching the correct position of the holes. The bearing blocks generally have slotted holes for final adjustment, back or forward.

The foot control pedal and rocker arms are now assembled into place. Two pieces of lin. x Jin. flat iron, 20in. long (J in the upper left diagram on page 135), are drilled with a Jin. hole Jin. from each end. Another piece of flat iron 2in. x Jin. x 34Jin. (K in same diagram) is drilled with a jin. hole lin. from one end. The other end is cut away to form a foot control pedal (KI) as shown in the drawing and a foot plate is welded on the top or two pieces of angle iron can be bolted together; 13in. from this end bore a Jin. hole to take a pivot pin. The supports for this assembly are the two pieces of l|in. x Jin. angle iron, 27Jin. long (L). A Jin. hole drilled 6in. from the front and in the same face as the holes previously described in L should give the correct position for the pivot pin, but it would be best to check this measurement before drilling. The pedal is required to bring the saw spindle assembly into an erect position to get the maximum cut from the Bin. saw.

To bring K out into correct alignment with the rocker assembly (D) a block of wood (K 4 in lower left diagram on page 135) is used which has a Jin. hole bored in it and which rests on the angle iron as shown in

the drawing.

To comply with the Department of Labour’s safety regulations a safety catch is fitted to the foot pedal as shown in the upper right diagram on page 135. When the saw will move forward freely when foot pressure is applied and will line up correctly, two pieces of lin. x jin. angle iron (M and N in diagram at upper left on page 135) 17Jin. long are placed in position. The front stop (N) should allow the saw to come forward about 1-jin. past top centre, and M should allow the saw to retract below the bench top. When fitting the i h.p. motor endeavour to get it in as close to the pivot shaft as possible, and make sure the pulley correctly lines up with the pulley on the saw spindle. To counterbalance the weight of the motor when the saw is coming into the vertical position two strong coiled springs are required. They can be about 2in. to 3in. long with a coil about lin. in diameter. They are connected to the appropriate eye bolts with split links. This arrangement allows the springs to collapse completely when the saw is below the table top, but to come into action when the saw is coming forward. Nuts on the bottom eye bolts give any adjustment that may be necessary. These are fixed to a piece of lin. x jin. angle iron, 13jin. long (O in the upper left and lower left diagrams on page 135). Though the foot pedal moves the saw forward when long lengths of timber are being crosscut, some arrangement has to be made to hold the saw in position for normal saw-bench work. This is done by the saw adjustment assembly shown in the middle diagram on page 137. A piece of jin. steel shafting 23in. long is threaded for about 12in. to 14in. of its length. The threaded end fits into a universal block (S) as

shown in the drawing. The other end fits into a similar block (SI) with a gin. hole and a collar each side. At the end is a plate or wheel for the turning handle (Q). SI is fixed to the angle iron QI (upper left diagram on page 135) by two Jin. bolts. The two fittings R are secured underneath the saw spindle (Zl) on the bolts nearest the saw. The assembly is made perfectly rigid by slipping S in between the two pieces of angle iron R and dropping in the two tapered pins. Any movement of the saw spindle is now done by the adjusting wheel, which takes the place of the rise and fall table. Saw-bench Top Three pieces of Bin. x fin. x 36in. dressed timber are required for the saw-bench top. A sheet of fin. resinbonded plywood could be used if procurable. The first board is fixed to the angle iron cross pieces just clear of the inside of the saw. Another board is placed next, and the third piece goes on the other side of the saw after the space for the throat piece has been cut away. For holding the boards on to the metal frame 3/16in. bolts with countersunk heads can be used. The throat opening should start lOin. from the front and extend for 20in. with a width of 2|in. To support the various throat plates used, two metal strips are screwed

underneath the ends of the opening, care being taken that they are clear of the saw. Crosscut Fence The crosscut fence should be left until the last when the bench can be used for rabbeting out the recess for the iron strips to be fitted on the fence. Take a piece of 2fin. x ljin. dressed timber about 3ft. long and on the If-in. edges cut recesses for taking lin. x Jin. flat iron on each side. For the edge to be placed next to the saw the iron is cut into two lengths, one piece 25in. and the other lOJin. This will leave a gap of jin. for the saw to come up to. On the other edge the iron is in one piece, 36in. x lin. x Jin. Screw these on with countersunk screws, making sure none comes near where the holes for the cutting-off pin or stop will be bored. When the saw is forward as far as possible make a mark on the bench top where the depth of cut will be Ijin. Now lower the saw to clear this mark, place the fence in position (making sure the gap between the two pieces of iron is in line with the saw and on the ljin. mark), clamp the fence lightly, and set it so as to be at right angles to the saw. Recheck the position and clamp the fence tightly. Now bore two fin. holes in the fence and through the bench top to come about 2in. from each edge of the top. Two pieces of -fin. dowelling about 2j-in. long are now glued into the fence, the ends being left flush with the top. The projecting pieces on the under side should be rounded off so that the fence will readily fit into place over the positioning holes. End clamps as shown in the diagram on page 138 can now be fitted. Now run the saw up into the fence. Remove

the saw and from this cut measure out the various standard lengths for all hive equipment as shown in the same diagram. Note that the measurement must be from the edge of the cut to the contact edge of the fin. cutting-off pin. This means that the centre punch marks for drilling, which should be well made, will be the length required plus 3/16in. When they are marked, recheck, as it is essential that these distances be accurate, as they are the standard for a y cuts. Use a small drill first, before using the f-in. drill. The holes go right through the two pieces of flat iron, The making up of the fences and guard should be easily followed from the drawing.

When the electrician is wiring up the electric motor, have the switch placed in a handy position on the bench. This can be on the front lefthand leg just underneath the bench top.

A chute made of metal or hardboard is necessary to keep the sawdust off the motor. This is fitted on to the saw spindle frame D. A temporary fitting can be seen in the bottom illustration on page 139.

If. the saw spindle is going to be used for boring or dowelling, a suitable shelf can be fitted on the side of the bench with two metal brackets. Boring height is controlled by the saw adjustment spindle.

To comply with the Department of Labour’s Woodworking Machinery Regulations it is necessary to enclose the sides of the bench as shown in the upper illustration on page 133. The material used can be metal, hardboard, plywood, or strong wire screen. Screws should be used for fixing the material to the frame.

A saw bench of the above type, though it has been designed to meet beekeepers’ requirements, can be used for home furniture joinery. One has also been used in the construction of

a house, including all window joinery and inside fittings.

Material Requirements

Timber

4 lengths 34in. long, dressed, 2tin. x Ilin, (legs) 3 lengths 36in. long, dressed, Sin. x gin. (bench top) 1 length 40in. • long, dressed, 3fin. x gin. (fences) 1 length 66in. long, dressed, 2fin. x gin. (throat plates) . 1 length 36in. long, dressed, 2|in. x l|in. (crosscutting fence) Approximate price £1 2s. 6d.

Iron Angle iron— A 2 lengths 27Jin. long lin. x Jin.; 5/16in. hole IJin. from each end B 2 lengths 23in. long IJin. x Jin. C and L 4 lengths 27Jin. long IJin. x Jin. H 2 lengths 12in. long lin. x Jin. M and N 2 lengths 17Jin. long lin. x Jin.; 5/16in. hole lin. from each end 0 1 length 13Jin. long lin. x Jin.; Jin. hole Sin. from each end P 2 lengths 24in. long lin. x Jin.; six 3/16in. holes to match bench top Q 1 length 17Jin. long IJin. x Jin. 1 length 20in. long 2in. x Jin. (ripping fence) 1 length 25in. long 2in. x Jin. (ripping fence) Flat iron 2 lengths sin. long lin. x Jin. (to hold throat plate) 2 lengths 36in. long lin. x Jin. (crosscut fence) 1 length 25in. long lin. x Jin. (ripping fence brace) D 1 length 50in. long 2in. x Jin. (rocker arm) E 2 lengths 18in. long IJin. x Jin. (rocker arm cross braces) G 2 lengths 4in. long 2in. x Jin. (top rocker arm) J 2 lengths 20in. long lin. x Jin. K 1 length 34Jin. long 2in. x Jin. (Jin. hole lin. from one end and Jin. hole 13in. from other end)

Shafting F 1 length 16in. long lin.-diameter steel shaft (to pivot rocker arm) 1 length 23in. long Jin.-diameter steel shaft (adjusting screw) 1 length 32in. long Jin.-diameter iron shaft (saw guard support): Bolts 12 engineer’s bolts Jin. x 5/16in. 10 engineer’s bolts 3Jin. x 5/16in. 1 engineer's bolt 3Jin. x Jin. 12 engineer’s bolts lin. x 5/16in. 24 countersunk bolts IJin. x Jin. 24 countersunk bolts lin., x 3/16in. Approximate price of iron (cut to . size) and bolts: £4 6s. Approximate Equipment price £ s. d. 1 J h.p. motor . . . . . . 14 0 0 1 A section V pulley, 4in. diameter, cast iron, fits motor . . 10 0 1 A section V pulley, 2 Jin. diameter, cast iron, fits saw spindle .. .. . . .. 9 0 2 lin. bearings or plummer blocks 16 0 1 A section V belt 27in. .. . . 8 6 Saw spindle to take dado cutters 5 2 6 1 Bin. crosscut saw .. . . 12 0 1 Sin. rip saw .. .. .. 12 0 1 set 6in. dado cutters (optional) 10 10 0

SAWS

Sawing of timber has become a very highly skilled trade, and as can be expected with a greater variety of jobs being done on the bench various types of saws and saw-teeth shapes have developed, each saw being used only for its particular job and each tradesman having his own modified idea of teeth shape. The beekeeper, however, will need only saws of a standard pattern, namely, the crosscut, rip, dado cutters, and possibly a combination saw. Care of Saws Care of the saw when not in use is a very important factor in preventing rust and damage to the teeth. The saws should always be kept in a hanging position. A good method is to drive a 2in. to 3in. nail into a board fixed on the wall of the workshop. Put - in a nail for each saw. To keep the saws away from the wood place three small tacks around each nail about 2in. from the centre and projecting from the board about Jin. These keep the saws away from the wood and assist in preventing rust. Saws not in continuous use should always be coated with grease. It is impossible to keep a good sharp edge on the teeth once rust has attacked this part of the saw. Types of Saws Crosscut saw: This is intended for cutting across the grain and is not satisfactory for ripping. The teeth are generally V shaped and are sharpened so that the tip of the tooth comes to a sharp point. Rip saw: This is used for cutting with the grain of the wood. The points of the teeth are filed square across to give a chisel point.

Combination saw: This saw has a combination of both crosscut and rip teeth and is suitable for doing odd jobs on the saw bench. However, it is recommended that when a run of ripping or crosscutting is to be done the appropriate saw should be used.

Hollow-ground, saw: A hollow-ground saw blade is used where a fine, smooth finish is desired. This blade requires no set, as it is tapered slightly from the edge to the centre to provide the necessary clearance. A rip saw of this type is recommended for frame making to give the smooth finish so desirable.

Controlled cut or Grupp saw: This differs from the conventional blade in that it has only eight teeth and the cutting tip projects only ,02in. above the rim of the saw. The saw produces chips rather than sawdust. It is sometimes called a safety saw because kick-backs are reduced to a minimum. Though these saws have been on the market for many years, they have not become popular.

Dado cutters: A dado saw is a device for cutting grooves out of timber. A complete set consists of two solid outside saws and a number of chipper blades of varying thickness, l/16in. to jin. or even thicker. The diameter of a set suitable for a beekeeper would be about 6in. with blades giving a total thickness of fin. or lin. By changing, the number of chipper blades varying sized grooves can be cut.

Drunken saws are sometimes called wobble saws because they are set on the saw spindle at an angle. When in motion the saw wobbles, the extent of movement depending on the degree of angle. A saw of this type should be of heavy gauge (sin.) and should have proper metal collars for varying the amount of angle or cut. The base of a cut made with a drunken saw is never perfectly flat unless the blade is specially prepared for this one width of cut. With this type of saw, especially with a wide cut, extra care should be taken in firmly holding the timber on to the saw; otherwise it is liable to be torn out of the operator’s hands because of the wobble.

Swage saw: This is a special saw very thin at the teeth and thicker than usual at the collar. It is thinned or

tapered on one side only, the other side being flat. This saw is used for slicing off narrow strips and when a saving of timber is necessary. In working position the bevel face of the saw faces the fence. Taper or splitting saw: This is much the same as the swage saw, except that it is tapered on both sides. It is used mainly for splitting narrow wood up the centre. Keeping Saws in Working Condition The quality and speed of the work turned out on a saw bench will depend .on the condition of the saw blade. A dull saw is dangerous because it requires additional pressure on the wood and tends to tear the material instead of cutting it. . 'i

Jointing: The first procedure in sharpening a saw is jointing or making the saw perfectly round. Before this is done the saw should be placed on the spindle and a mark or dab of paint placed on both the saw blade and the inside collar so that the saw will always be replaced in this same position on the spindle. Larger saw benches generally have a pin which serves the same purpose. The jointing is carried out by holding an abrasive stone in contact with the revolving blade. The safest way of doing this is to lower the saw until it is below bench level. Now bring it up very slowly until it just touches the stone. Stop, examine the saw, and see if all the teeth have been touched. If not, repeat the process.’ Now remove the blade and place it in the sharpening jig. The correct set on the teeth is essential for a good cutting saw. Setting and jointing of the saw should not be necessary each time it is sharpened.

Setting is bending the tips of the teeth alternately right and left. This can readily be done with a hand saw set. To make sure each tooth is set an equal amount it is wise to use a set gauge. No more set than is necessary to give a clear cut should be used. A rule to remember is that the maximum amount of set should never be more than a quarter of the thickness of the blade at the tooth; for example, a blade Jin. thick should never have a set of more than l/32in. Never bend the teeth over more than a third of the length of the tooth.

Sharpening: Place the saw in a suitable clamp at a good working height. See that the teeth are just above the top of the clamp; otherwise the saw will vibrate and make it impossible to get a good edge on the teeth. Suitable files will be required, a 6in. or 7in. slim taper, 3-corner file for the crosscut saw and an Bin. mill file with round edge for the rip blade.

In sharpening crosscut teeth file them as nearly as possible the same as when the saw was new. The file, which cuts only on the forward stroke, must be held at an angle with the blade, both vertically and horizontally, so that the teeth will be shaped as shown in .the drawing at upper left on page 144. The teeth with set away from the operator are the ones to file. When these are done the saw is reversed and the remaining teeth filed. Care should be taken that no unevenness is left in the base of the gullet, as this is liable to collect sawdust and cause heating of the saw.

In sharpening a rip saw use the mill file with the rounded edge in the gullet and file square across the front of the tooth, with the file at right angles to the blade. The file should be slightly tilted to give the tooth a small amount of hook. After this stroke the same file is run over the top of the tooth until the jointing marks are removed. The saw is again reversed to

complete the other set of teeth. Though the correct sharpening of the teeth is important, it is also necessary to keep the gullet to its original depth to allow the removal of sawdust. The base of the gullet should be left smooth and round.

The combination saw is sharpened by following the instructions given for both the crosscut and rip saws. In this saw the rip or raker teeth are filed slightly below the points of the crosscut teeth.

Dado cutters should be jointed with all the chipper blades included and filed by practically the same method as for an ordinary blade. The mill file should be run flat over the top of the chipper blades until the jointing mark is removed, care being taken that sufficient clearance is given to the back of the tooth.

It is recommended that periodically all saws should be sent to a local saw sharpener for reshaping of teeth and gulleting. USES OF FENCES AND JIGS At no time should timber be cut without the use of a fence. The short fence is used for normal ripping purposes. The front edge of this fence should not go beyond the gullet of the saw. This gives an easy flow of timber past the saw and greatly reduces the possibility of throwback. The cutting is also more accurate. The long fence extends past the back of the saw and is used when grooving or rabbeting, when part of the timber is always hard against the fence. This fence must be in perfect alignment with the saw. Never attempt to rip timber with this type of fence.

Crosscutting

Square the crosscutting fence at right angles to the saw. Now trim the end of a wide board and with a carpenter’s square check the cut. Make sure the square fits the edge of the wood resting against the fence.

When the long boards for supers or frames are being cut, care should be taken to select the timber for the appropriate part, making sure not to cut knots on ends which will require further resawing or nailing.

A stick marked with the lengths of the various hive components is very useful for quickly marking out a length of timber in the various sizes to avoid knots near the saw cut and to eliminate waste.

Should any of the timber have a curved edge, care should be taken in how it is sawn. The rounded or convex edge should always be up to the crosscutting fence to avoid jamming of the saw (see drawing). Accurate right-angle cuts cannot be secured this way, so it is best to cut badly curved timber into slightly longer lengths and then to recut both ends again, with the hollow side this time to the fence.

The riving knife, made of quality steel, and guard should be used, care being taken that the riving knife is never more than -gin. from the back of the saw and in correct alignment. The floor around the bench should be kept clear of small blocks of wood.

Ripping

Always use a push stick when operating the ripping saw. Fix the saw to the required height above the bench top. Allow one-third extra to the thickness of the timber being ripped. If too much saw is showing, ¥ it will give a rough cut with tear on the

underside of the board. If the saw is too low, it will clog and heat up. A hot saw will wander and soon spoil. When ripping off strips, such as top bars, cut off four, keeping them in the same position as they came off the board, place them together, and measure them back and front. If the two measurements are the same, no adjustments are necessary. However, if there is a slight difference, pack out the fence to correspond with the greater measurement.

Make sure the riving knife and guard are used.

Grooving

When using the dado cutters for grooving or cutting out hand grips make sure the chipper blades are spaced evenly around the spindle. This gives an even cut. A throat plate with the minimum cut out should always be used. If the cutters become clogged up, it is best to dismantle the set and clean it. It is not desirable to have any more chipper blades in the set than are actually required.

The chipper blades are always enclosed between the two saws.

Testing for Crack in Saw Blade

A saw should be in sound condition to do its job correctly and give the operator an assurance of safety. A cracked saw should never be used, and to detect even the smallest of fractures the following method can be used. Clean the saw and dip it in kerosene for a short period, say 5 minutes. Clean off all the kerosene with a rag and dust the blade with powdered chalk. After a little while the crack will show up because of retained kerosene soaking into the chalk. It is not worth while trying to repair the saw, as small saws are not very costly to replace. The main thing is to replace a damaged saw immediately. Do not wait until it flies to pieces.

CARE OF TIMBER

Timber sawn from the log should be correctly stacked as soon as possible, particularly Pinus radiata, which will deteriorate very quickly if left unstacked, even for a very short period, after it has been sawn. The beekeeper who is securing his timber directly from the sawmill should make arrangements for delivery as soon as possible after sawing. He should also try to get his lOin. boards sawn a full inch thick if possible. This will allow the boards, when dry, to be dressed down to -gin. Otherwise he will find the timber measuring 13/16in.

Method of Drying

Freshly sawn timber should be stacked to get rid of most of the sap moisture as quickly as possible. The

usual method of doing this is to stack the timber in the form of a tent, or an inverted V, with the boards resting edgewise on the supporting frame, thus preventing sagging. Timber stacked this way has plenty of air moving through it all the time. Rain and frost will also help to hasten the removal of sap moisture. To prevent detefioration of the timber where the boards would meet at the top short lin. fillets are placed between each board. These can be kept in place by lightly nailing them to the beam or ridge of the frame. The next stage is to get the boards dry enough for use. This is done by horizontal stacking. A suitable foundation has first to be prepared to take the weight of the timber. Short lengths of 4in. x 3in. timber are spaced about 3ft. apart. To give the timber a slope of about Ift. in 12ft. the blocks are built up at one end to Ift. and the intermediate blocks lined up accordingly. The boards can now be placed in position. If the stack is to be two or three boards wide, leave an inch space between each board. Now place wooden lin. x lin. fillets directly above the 4in. x 3in. sleepers and across the first layer of boards. Carry on until the. stack is completed, making sure each fillet comes directly above the sleepers. The completed stack can be covered on the top with a few sheets of iron, and grass should be kept down from around the sleepers. Timber carefully stacked in this way will come out in good, straight boards and ready for the planer. The time taken to dry timber thoroughly will depend largely on general weather conditions, but if possible, at least 12 months should be allowed.

CALCULATION OF SPEEDS AND PULLEY SIZES

Anyone working with machinery should know how to calculate pulley sizes and shaft speeds. Four factors govern the speed of a honey pump, extractor, or saw. These are speed of motor, size of pulley on motor shaft, speed of machine to be driven, and size of pulley on machine. In any machine set-up at least two of these items are usually known. The speed of the electric motor is always shown on the plate fastened to the motor, and usually known also is the speed at which the particular machine has to run. There are several methods of calculating the unknown factors. A simple method is as follows: — Speed of motor X diameter of pulley on motor should = speed of driven machine X diameter of pulley on driven shaft. If the driven machine (for example, an extractor) is to run at a slower speed than the motor, the pulley on the motor will be smaller than that on the driven machine. As the smallest

V pulley is about 2in. to 2|in. in diameter, the size of the larger pulley is worked out thus: — Speed of motor (1450 r.p.m.) X size of pulley on motor (say 2in.) 2900. Speed of extractor (200 r.p.m.) X size of pulley (?) 2900 H- 200 = 14Jin. Because with a saw the speed required is greater than that of the motor, the smaller pulley goes on the saw spindle. Speed of motor (1450 r.p.m.) X diameter of pulley on motor (?) = Speed of saw spindle (2500 r.p.m.) X diameter of pulley on shaft (2Mn.) = 6250 -r- 1450 = approximately 4Jin. pulley. For practical purposes the diameter of the V pulley, as sold, is measured from the outside edge. V belts and pulleys are sold in two sizes, called A or B section. The A section belt measures Jin. across the top, and the B section measures fin., with pulleys corresponding. The standard used by British manufacturers for designating the thickness or gauge of the saw is the B.W.G. (Birmingham Wire Gauge). For ripping timber into small pieces, such as top' bars for bee frames, a very thin saw is desirable to reduce the amount of waste. Sometimes use of such a saw enables an extra bar to be cut from a piece . of timber. The following table gives the measurements of a gauge range that is likely to be encountered: — Gauge number Thickness . (8.W.G.) in inches 21 .. . . .. .032 approx. l/32in. 20 035 19 042 18 .. . . .. .049 17 058 16 . . .. .. .065 approx. l/16in. 15 072 14 .. .. ... .083 13 095 12 109 11 . . .. .. .120 approx, Jin. 10 134 9 148 8 165 Electrical Power Unit A thousand watts used for 1 hour equals 1 unit. As this is the basis of payment for electricity supply, it will be of interest to know just what power is being used by the various machines. Units used per hour 1000-watt heating element .. 1 J h.p. motor .. .. .. .185 I h.p. motor . . . . . . .24 J h.p. motor . . .. .. .37 1 h.p. motor . . .. .. .74 Always remember: Don’t get too familiar with the saw, and keep your mind on the job and your fingers on your hand. “Safety Hints for Operators of Circular Saws” is a pamphlet published by the Department of Labour and the Department of Health, and is available on application, free of charge.