WOOD HAND TOOLS.
4. SCRAPING TOOLS.
Scraping tools are of such nature that they can only abrade or smooth surfaces.
| 142 | 143 | 144 | 145 | 146 | 147 | 148 |
Fig. 142. Auger-Bit-File. Fig. 143. Single-Cut Blunt, Flat, Bastard File. Fig. 144. Three-Square Single-Cut File. Fig. 145. Open Cut, Taper, Half-Round File. Fig. 146. Double-Cut File. Fig. 147. Cabinet Wood-Rasp. Fig. 148. File-Card. |
Files. Figs. 142-146, are formed with a series of cutting edges or teeth. These teeth are cut when the metal is soft and cold and then the tool is hardened. There are in use at least three thousand varieties of files, each of which is adapted to its particular purpose. Lengths are measured from point to heel exclusive of the tang. They are classified: (1) according to their outlines into blunt, (i. e., having a uniform cross section thruout), and taper; (2) according to the shape of their cross-section, into flat, square, three-square or triangular, knife, round or rat-tail, half-round, etc.; (3) according to the manner of their serrations, into single cut or "float" (having single, unbroken, parallel, chisel cuts across the surface), double-cut, (having two sets of chisel cuts crossing each other obliquely,) open cut, (having series of parallel cuts, slightly staggered,) and safe edge, (or side,) having one or more uncut surfaces; and (4) according to the fineness of the cut, as rough, bastard, second cut, smooth, and dead smooth. The "mill file," a very common form, is a flat, tapered, single-cut file.
Rasps, Fig. 147, differ from files in that instead of having cutting teeth made by lines, coarse projections are made by making indentations with a triangular point when the iron is soft. The difference between files and rasps is clearly shown in Fig. 149.
Fig. 149. a. Diagram of a Rasp Tooth.
b. Cross-Section of a Single-Cut File.
It is a good rule that files and rasps are to be used on wood only as a last resort, when no cutting tool will serve. Great care must be taken to file flat, not letting the tool rock. It is better to file only on the forward stroke, for that is the way the teeth are made to cut, and a flatter surface is more likely to be obtained.
Both files and rasps can be cleaned with a file-card, Fig. 148. They are sometimes sharpened with a sandblast, but ordinarily when dull are discarded.
Scrapers are thin, flat pieces of steel. They may be rectangular, or some of the edges may be curved. For scraping hollow surfaces curved scrapers of various shapes are necessary. Convenient shapes are shown in Fig. 150. The cutting power of scrapers depends upon the delicate burr or feather along their edges. When properly sharpened they take off not dust but fine shavings. Scrapers are particularly useful in smoothing cross-grained pieces of wood, and in cleaning off glue, old varnish, etc.
Fig. 150. Molding-Scrapers.
There are various devices for holding scrapers in frames or handles, such as the scraper-plane, Fig. 111, [p. 79], the veneer-scraper, and box-scrapers. The veneer-scraper, Fig. 151, has the advantage that the blade may be sprung to a slight curve by a thumb-screw in the middle of the back, just as an ordinary scraper is when held in the hands.
Fig. 151. Using a Veneer-Scraper.
In use, Fig. 152, the scraper may be either pushed or pulled. When pushed, the scraper is held firmly in both hands, the fingers on the forward and the thumbs on the back side. It is tilted forward, away from the operator, far enough so that it will not chatter and is bowed back slightly, by pressure of the thumbs, so that there is no risk of the corners digging in. When pulled the position is reversed.
Fig. 152. Using a Cabinet-Scraper.
One method of sharpening the scraper is as follows: the scraper is first brought to the desired shape, straight or curved. This may be done either by grinding on the grindstone or by filing with a smooth, flat file, the scraper, while held in a vise. The edge is then carefully draw-filed, i. e., the file, a smooth one, is held (one hand at each end) directly at right angles to the edge of the scraper, Fig. 153, and moved sidewise from end to end of the scraper, until the edge is quite square with the sides. Then the scraper is laid flat on the oilstone and rubbed, first on one side and then on the other till the sides are bright and smooth along the edge, Fig. 154. Then it is set on edge on the stone and rubbed till there are two sharp square corners all along the edge, Fig. 155. Then it is put in the vise again and by means of a burnisher, or scraper steel, both of these corners are carefully turned or bent over so as to form a fine burr. This is done by tipping the scraper steel at a slight angle with the edge and rubbing it firmly along the sharp corner, Fig. 156.
Fig. 153. Sharpening a Cabinet-Scraper: 1st Step, Drawfiling.
Fig. 154. Sharpening a Cabinet-Scraper: 2nd Step, Whetting.
Fig. 155. Sharpening a Cabinet-Scraper: 3rd Step, Removing the Wire-Edge.
Fig. 156. Sharpening a Cabinet-Scraper: 4th Step, Turning the Edge.
To resharpen the scraper it is not necessary to file it afresh every time, but only to flatten out the edges and turn them again with slightly more bevel. Instead of using the oilstone an easier, tho less perfect, way to flatten out the burr on the edges is to lay the scraper flat on the bench near the edge. The scraper steel is then passed rapidly to and fro on the flat side of the scraper, Fig. 157. After that the edge should be turned as before.
Fig. 157. Resharpening a Cabinet-Scraper: Flattening the Edge.
Sandpaper. The "sand" is crushed quartz and is very hard and sharp. Other materials on paper or cloth are also used, as carborundum, emery, and so on. Sandpaper comes in various grades of coarseness from No. 00 (the finest) to No. 3, indicated on the back of each sheet. For ordinary purposes No. 00 and No. 1 are sufficient. Sandpaper sheets may readily be torn by placing the sanded side down, one-half of the sheet projecting over the square edge of the bench. With a quick downward motion the projecting portion easily parts. Or it may be torn straight by laying the sandpaper on a bench, sand side down, holding the teeth of a back-saw along the line to be torn. In this case, the smooth surface of the sandpaper would be against the saw.
Sandpaper should never be used to scrape and scrub work into shape, but only to obtain an extra smoothness. Nor ordinarily should it be used on a piece of wood until all the work with cutting tools is done, for the fine particles of sand remaining in the wood dull the edge of the tool. Sometimes in a piece of cross-grained wood rough places will be discovered by sandpapering. The surface should then be wiped free of sand and scraped before using a cutting tool again. In order to avoid cross scratches, work should be "sanded" with the grain, even if this takes much trouble. For flat surfaces, and to touch off edges, it is best to wrap the sandpaper over a rectangular block of wood, of which the corners are slightly rounded, or it may be fitted over special shapes of wood for specially shaped surfaces. The objection to using the thumb or fingers instead of a block, is that the soft portions of the wood are cut down faster than the hard portions, whereas the use of a block tends to keep the surface even.
Steel wool is made by turning off fine shavings from the edges of a number of thin discs of steel, held together in a lathe. There are various grades of coarseness, from No. 00 to No. 3. Its uses are manifold: as a substitute for sandpaper, especially on curved surfaces, to clean up paint, and to rub down shellac to an "egg-shell" finish. Like sandpaper it should not be used till all the work with cutting tools is done. It can be manipulated until utterly worn out.
5. POUNDING TOOLS.
The hammer consists of two distinct parts, the head and the handle. The head is made of steel, so hard that it will not be indented by hitting against nails or the butt of nailsets, punches, etc., which are comparatively soft. It can easily be injured tho, by being driven against steel harder than itself. The handle is of hickory and of an oval shape to prevent its twisting in the hand.
Hammers may be classified as follows: (1) hammers for striking blows only; as, the blacksmith's hammer and the stone-mason's hammer, and (2) compound hammers, which consist of two tools combined, the face for striking, and the "peen" which may be a claw, pick, wedge, shovel, chisel, awl or round head for other uses. There are altogether about fifty styles of hammers varying in size from a jeweler's hammer to a blacksmith's great straight-handled sledge-hammer, weighing twenty pounds or more. They are named mostly according to their uses; as, the riveting-hammer, Fig. 159, the upholsterer's hammer, Fig. 160, the veneering-hammer, Fig. 162, etc. Magnetized hammers, Fig. 161, are used in many trades for driving brads and tacks, where it is hard to hold them in place with the fingers.
| 158 | 159 | 160 | 161 | 162 |
Fig. 158. Claw-Hammer. Fig. 159. Riveting-Hammer. Fig. 160. Upholster's Hammer. Fig. 161. Magnetized Hammer. Fig. 162. Veneering-Hammer. |
In the "bell-faced" hammer, the face is slightly convex, in order that the last blow in driving nails may set the nail-head below the surface. It is more difficult to strike a square blow with it than with a plain-faced hammer. For ordinary woodwork the plain-faced, that is, flat-faced claw-hammer, Fig. 158, is best. It is commonly used in carpenter work.
It is essential that the face of the hammer be kept free from glue in order to avoid its sticking on the nail-head and so bending the nail. Hammers should be used to hit iron only; for hitting wood, mallets are used. In striking with the hammer, the wrist, the elbow and the shoulder are one or all brought into play, according to the hardness of the blow. The essential precautions are that the handle be grasped at the end, that the blow be square and quick, and that the wood be not injured. At the last blow the hammer should not follow the nail, but should be brought back with a quick rebound. To send the nail below the surface, a nailset is used. (See below.)
The claw is used for extracting nails. To protect the wood in withdrawing a nail a block may be put under the hammer-head. When a nail is partly drawn, the leverage can be greatly increased by continuing to block up in this way, Fig. 163.
Fig. 163. Drawing a Nail with Claw-Hammer.
Fig. 164. Mallets.
The mallet, Fig. 164, differs from the hammer in having a wooden instead of a steel head. A maul or beetle is a heavy wooden mallet. The effect of the blow of a mallet is quite different from that of a hammer, in that the force is exerted more gradually; whereas the effect of the hammer blow is direct, immediate, and local, and is taken up at once. But a mallet continues to act after the first impulse, pushing, as it were. This is because of the elasticity of the head. A chisel, therefore, should always be driven with a mallet, for the chisel handle would soon go to pieces under the blows of a hammer, because of their suddenness; whereas the mallet blow which is slower will not only drive the blade deeper with the same force, but will not injure the handle so rapidly. Mallet-heads are made square, cylindrical, and barrel-shaped. Carver's mallets are often turned from one piece, hammer and head on one axis.
Nailsets, Fig. 165, are made with hardened points, but softer butts, so that the hammer will not be injured. They were formerly made square when nail heads were square, but now round ones are common. To obviate slipping, some have "cup points," that is, with a concave tip, and some spur points.
Fig. 165. Using a Nailset.
To keep the nailset in its place on the nail-head it may be held closely against the third finger of the left hand, which rests on the wood close to the nail. When a nailset is lacking, the head of a brad, held nearly flat, may be used. But care is necessary to avoid bruising the wood.
6. HOLDING TOOLS.
A. Tools for Holding Work.
The advance in ease of handworking may largely be measured by the facilities for holding materials or other tools. The primitive man used no devices for holding except his hands and feet. The Japanese, who perhaps are the most skilful of joiners, still largely use their fingers and toes. On the other hand, Anglo-Saxons have developed an enormous variety of methods for holding work and tools.
Fig. 166. Bench made with Pinned Mortise-and-Tenon Joints, Low Back.
Fig. 167. Woodworking Bench used at Pratt Institute, Showing Self-Adjusting Upright Vise.
Benches. The essential features of a work-bench are a firm, steady table with a vise and places for tools. The joints are either pinned or wedged mortise-and-tenon, or draw-bolt joints. The best benches are made of maple, the tops being strips joined or tongued-and-grooved together. It is common also to have a trough at the back of the top of the bench, i. e., a space 6" or 8" wide, set lower than the upper surface, in which tools may be placed so as not to roll off. A low pillow, fastened at the left hand end of the trough, on which to set planes in order that the edge of the cutter may not be injured, is an advantage. The tool-rack is of capital importance. It has been common in school benches to affix it to a board, which rises considerably above the top of the bench, Fig. 169, but a better plan is to have the top of it no higher than the bench-top, Fig. 166. Then the light on the bench is not obscured, and when a flat top is needed for large work it can readily be had by removing the tools. Elaborate benches with lock drawers are also much used in the shops of large city schools.
Fig. 168. A Rapid-Acting Vise.
Vises for holding wood are of three general styles, (1) those with an upright wooden jaw, Fig. 167, which holds wide pieces of work well. They are now made with an automatic adjusting device by which the jaw and the face of the bench are kept parallel; (2) wooden vises with a horizontal jaw, guided by parallel runners, Fig. 166, and, (3) metal rapid-acting vises, Fig. 168. The latter are the most durable and in most respects more convenient. Special vises are also made for wood-carvers, for saw-filing, etc.
Fig. 169. Holding a Large Board in Vise for Planing.
The best woodworking benches are equipped with both side- and tail-vises. The tail-vise is supplemented by movable bench-stops for holding pieces of different lengths. In planing the side of a board it is held in place between the tail-vise and one of the bench-stops. A board should not be squeezed sidewise between the jaws of a vise when it is to be planed, lest it be bent out of shape. In planing the edge of a board it is ordinarily held in the side-vise. A long board, one end of which is in the vise, may also need to be supported at the other end. This may be done by clamping to it a handscrew, the jaw of which rests on the top of the bench, Fig. 169. When the vise is likely to be twisted out of square by the insertion of a piece of wood at one end of it, it is well to insert another piece of equal thickness at the other end of the vise to keep it square, as in Fig. 120, [p. 82]. In this case, (Fig. 120,) the extra piece also supports the piece being worked upon.
The vise is also of great use in carrying on many other processes, but a good workman does not use it to the exclusion of the saw-horse and bench-hook.
Horses are of great use both for the rough sawing of material and in supporting large pieces during the process of construction. The common form is shown in Fig. 170, but a more convenient form for sawing has an open top, as in Fig. 171.
Fig. 170. Saw-Horse.
Fig. 171. Saw-Horse.
The picture-frame-vise, Fig. 172, is a very convenient tool for making mitered joints, as in picture-frames. The vise holds two sides firmly so that after gluing they may be either nailed together or a spline inserted in a saw cut previously made. See Fig. 268, No. [55], [p. 181]. If the last joint in a picture-frame does not quite match, a kerf may be sawn at the junction of the two pieces, which can then be drawn close together.
Fig. 172. Picture-Frame-Vise.
Handscrews, Fig. 173, consist of four parts, the shoulder jaw and the screw jaw, made of maple, and the end spindle and the middle spindle, made of hickory. The parts when broken can be bought separately. Handscrews vary in size from those with jaws four inches long to those with jaws twenty-two inches long. The best kind are oiled so that glue will not adhere to them. In adjusting the jaws, if the handle of the middle spindle is held in one hand, and the handle of the end spindle in the other hand, and both are revolved together, the jaws may be closed or opened evenly, Fig. 174. In use care must be taken to keep the jaws parallel, in order to obtain the greatest pressure and to prevent the spindles from being broken. It is always important to have the jaws press on the work evenly. To secure this, the middle spindle should be tightened first, and then the end spindle. Handscrews are convenient for a great variety of uses, as clamping up glued pieces, holding pieces together temporarily for boring, Fig. 247, [p. 152], holding work at any desired angle in the vise, as for chamfering or beveling, Fig. 175, etc.
Fig. 173. Handscrew.
Fig. 174. Adjusting Handscrew.
Fig. 175. Using a Handscrew to hold a Board at an Angle.
Clamps are made of both wood and iron, the most satisfactory for speed, strength, and durability are steel-bar carpenter clamps, Fig. 176. They vary in length from 1½ ft. to 8 ft. The separate parts are the steel bar A, the cast-iron frame B, the tip C into which fits the screw D, on the other end of which is the crank E, and the slide F with its dog G, which engages in the notches on the bar. Any part, if broken, can be replaced separately.
Fig. 176. Steel-Bar Carpenter's Clamp. a. Steel Bar. b. Frame. c. Tip. d. Screw. e. Crank. f. Slide. g. Dog.
Iron Handscrews, also called C clamps and carriage-makers' clamps. Fig. 177, are useful in certain kinds of work, as in gluing in special places and in wood-carving. All iron clamps need blocks of soft wood to be placed between them and the finished work.
Fig. 177. Iron Handscrew, (Carriage-Maker's Clamp).
Pinch-dogs, Fig. 178, are a convenient device for drawing together two pieces of wood, when injury to the surfaces in which they are driven does not matter. They vary in size from ¾" to 2¾". For ordinary purposes the smallest size is sufficient. For especially fine work, double-pointed tacks, properly filed, are convenient.
Fig. 178. Pinch-Dog.
The bench-hook, Fig. 179, is a simple device for holding firmly small pieces of work when they are being sawn, chisled, etc. It also saves the bench from being marred. The angles should be kept exactly square.
Fig. 179. Bench-Hook.
The miter-box, Fig. 180, is a similar device with the addition of a guide for the saw. The iron miter-box, Fig. 181, with the saw adjustable to various angles, insures accurate work.
Fig. 180. Miter-Box.
Fig. 181. Iron Miter-Box.
Such tools as pliers, Fig. 182, pincers, Fig. 183, and nippers, Fig. 184, made for gripping iron, are often useful in the woodworking shop. So are various sorts of wrenches; as fixed, socketed, adjustable, monkey- and pipe-wrenches.
| Fig. 182. Pliers. | Fig. 183. Pincers. | Fig. 184. Nippers. |
B. Tools for holding other tools.
The brace or bit-stock, Fig. 185, holds all sorts of boring tools as well as screwdrivers, dowel-pointers, etc. The simple brace or bit-stock consists of a chuck, a handle, and a knob, and is sufficient for ordinary use; but the ratchet-brace enables the user to bore near to surfaces or corners where a complete sweep cannot be made. It is also useful where sufficient power can be applied only at one part of the sweep. By means of pawls which engage in the ratchet-wheel, the bit can be turned in either direction at the will of the user. The size of the brace is indicated by the "sweep," that is, the diameter of the circle thru which the swinging handle turns. To insert a bit or other tool, Fig. 186, grasp firmly with one hand the sleeve of the chuck pointing it upward, and revolve the handle with the other hand, unscrewing the sleeve until the jaws open enough to admit the whole tang of the bit. Then reverse the motion and the bit will be held tightly in place. Various hand-, breast-, bench-, bow-drills and automatic drills are of use in doing quick work and for boring small holes, Fig. 187.
Fig. 185. Ratchet-Brace.
Fig. 186. Inserting a Bit in Stock.
Fig. 187. Hand-Drill.
The screwdriver, Fig. 188, is a sort of holding tool for turning, and so driving screws. Various devices have been tried to prevent the twisting in the handle. This is now practically assured in various makes. The other important matter in a screwdriver is that the point be of the right temper, so as neither to bend nor to break. If the corners break they can be reground, but care should be taken not to make the angle too obtuse or the driver will slip out of the slot in the screw-head. The bevel should have a long taper. A shop should be equipped with different sizes of screwdrivers to fit the different sizes of screws. Screwdrivers vary in size, the shank ranging in length from 2½" to 18". A long screwdriver is more powerful than a short one, for the screwdriver is rarely exactly in line with the axis of the screw, but the handle revolves in a circle. This means an increased leverage, so that the longer the screwdriver, the greater the leverage.
| 188 | 189 | 190 |
|
Fig. 188. Screwdriver. Fig. 189. Screwdriver-Bit. Fig. 190. Spiral Screwdriver. |
For heavy work, screwdriver-bits, Fig. 189, in a bit-stock are useful, and for quick work, the spiral screwdriver, Fig. 190, and for small work, the ratchet-screwdriver.
7. MEASURING AND MARKING TOOLS.
It is a long step from the time when one inch meant the width of the thumb, and one foot meant the length of the foot, to the measuring of distances and of angles which vary almost infinitesimally. No such accuracy is necessary in measuring wood as in measuring metal, but still there is a considerable variety of tools for this purpose.
For measuring distances, the rule, Fig. 191, is the one in most common use. It is usually made of boxwood. For convenience it is hinged so as to fold. A rule is called "two-fold" when it is made of two pieces, "four-fold" when made of four pieces, etc. When measuring or marking from it, it can be used more accurately by turning it on edge, so that the lines of the graduations may come directly against the work. The one in most common use in school shops, is a two-foot, two-fold rule. Some instructors prefer to have pupils use a four-fold rule, because that is the form commonly used in the woodworking trades. Steel bench-rules, Fig. 192, are satisfactory in school work because unbreakable and because they do not disappear so rapidly as pocket rules. They need to be burnished occasionally.
Fig. 191. Two-Foot Rule. Two Fold.
Fig. 192. Steel Bench-Rule.
The steel square, Figs. 193, 194, 196, 197, is useful, not only as a straight-edge and try-square, but also for a number of graduations and tables which are stamped on it. There are various forms, but the one in most common use consists of a blade or "body" 24" × 2" and a "tongue," 16" × 1½", at right angles to each other. Sargent's trade number for this form is 100. It includes graduations in hundredths, thirty-seconds, sixteenths, twelfths, tenths, and eighths of an inch, also a brace-measure, an eight-square measure, and the Essex board-measure. Another style, instead of an Essex board-measure, and the hundredths graduation has a rafter-table. The side upon which the name of the maker is stamped, is called the "face," and the reverse side the "back."
The brace-measure is to be found along the center of the back of the tongue, Fig. 193. It is used thus: the two equal numbers set one above the other represent the sides of a square, and the single number to their right, represents in inches and decimals, the diagonal of that square.
| E. g., | 54 | 76.37 means thata square the sides of which are 54" would have adiagonal of 76.37". |
| 54 |
For determining the length of the long side (hypothenuse) of a right angle triangle, when the other two given sides are not equal, the foot rule, or another steel square may be laid diagonally across the blade and arm, and applied directly to the proper graduations thereon, and the distance between them measured on the rule. If the distance to be measured is in feet, use the 1⁄12" graduations on the back of the square.
To use the octagonal (or 8-square) scale, Fig. 194, which is along the center of the face of the tongue, with the dividers, take the number of spaces in the scale to correspond with the number of inches the piece of wood is square, and lay this distance off from the center point, on each edge of the board. Connect the points thus obtained, diagonally across the corners, and a nearly exact octagon will be had. E.g., on a board 12" square, Fig. 195, find A.B.C.D., the centers of each edge. Now with the dividers take 12 spaces from the 8-square scale. Lay off this distance on each side as A' A" from A, B' B" from B, etc. Now connect A" with B', B" with C', C" with D', D" with A', and the octagon is obtained.
Fig. 195. Method of Using the Eight-Square Scale on the Steel-Square.
In making a square piece of timber octagonal, the same method is used on the butt, sawed true. When the distance from one center is laid off, the marking-gage may be set to the distance from the point thus obtained to the corner of the timber, and the piece gaged from all four corners both ways. Cutting off the outside arrises to the gaged lines leaves an octagonal stick.
The board-measure is stamped on the back of the blade of the square, Fig. 196. The figure 12 on the outer edge of the blade is the starting point for all calculations. It represents a 1" board, 12" wide, and the smaller figures under it indicate the length of boards in feet. Thus a board 12" wide, and 8' long measures 8 square feet and so on down the column. To use it, for boards other than 12" wide:—find the length of the board in feet, under the 12" marked on the outer edge of the blade, then run right or left along that line to the width of the board in inches. The number under the width in inches on the line showing the length in feet, gives the board feet for lumber 1" thick.
For example, to measure a board 14' long, and 11" wide,—under the figure 12, find 14 (length of the board); to the left of this, under 11 is the number 12.10; 12' 10" is the board-measure of the board in question. Since a board 12' long would have as many board feet in it as it is inches wide, the B. M. is omitted for 12' boards. Likewise a board 6' long would have ½ the number of board feet that it is inches wide. If the board is shorter than the lowest figure given (8) it can be found by dividing its double by 2.; e. g., to measure a board 5' long and 9" wide, take 10 under the 12, run to the left of the number under 9, which is 7' 6"; ½ of this would be 3' 9", the number of board feet in the board.
If the board to be measured is longer than any figure given, divide the length into two parts and add the result of the two parts obtained separately. For example, for a board 23' long and 13" wide,—take 12' × 13" =13'; add to it, 11' × 13"=11' 11"; total, 24'11".
A good general rule is to think first whether or not the problem can be done in one's head without the assistance of the square.
The table is made, as its name, Board-Measure (B. M.) implies, for measuring boards, which are commonly 1" thick. For materials more than 1" thick, multiply the B. M. of one surface by the number of inches thick the piece measures.
The rafter-table is found on the back of the body of the square, Fig. 197. Auxiliary to it are the twelfth inch graduations, on the outside edges, which may represent either feet or inches.
Fig. 198. The "Run" and "Rise" of a Rafter.
By the "run" of the rafter is meant the horizontal distance when it is set in place from the end of its foot to a plumb line from the ridge end, i. e., one half the length of the building, Fig. 198. By the "rise" of the rafter is meant the perpendicular distance from the ridge end to the level of the foot of the rafter. By the pitch is meant the ratio of the rise to twice the run, i. e., to the total width of the building. In a ½ pitch, the rise equals the run, or ½ the width of the building; in a ⅓ pitch the rise is ⅓ the width of the building; in a ¾ pitch the rise is ¾ the width of the building.
To find the length of a rafter by the use of the table, first find the required pitch, at the left end of the table. Opposite this and under the graduation on the edge representing the run in feet, will be found the length of the rafter; e.g., a rafter having a run of 12' with a ¼ pitch, is 13' 5" long, one with a run of 11' and a ⅓ pitch, is 13' 28⁄12", one with a run of 7' and a ⅝ pitch, is 11' 26⁄12" long, etc.
When the run is in inches, the readings are for 1⁄12 of the run in feet: e.g., a rafter with a run of 12" and a ¼ pitch is 135⁄12", one with a run of 11" and a ⅓ pitch, is 133⁄12". Where the run is in both feet and inches, find the feet and the inches separately; and add together; e.g., a rafter with a run of 11' 6", and a ½ pitch, is 15' 68⁄12" + 86⁄12" = 16' 32⁄12".
The lumberman's board-rule, Fig. 199. To measure wood by it, note the length of the board in feet at the end of the measure. The dot nearest the width (measured in inches) gives the B. M. for lumber 1" thick.
The try-square, Fig. 200, which is most commonly used for measuring the accuracy of right angles, is also convenient for testing the width of a board at various places along its length, for making short measurements, and as a guide in laying out lines with a pencil or knife at right angles to a surface or edge. The sizes are various and are indicated by the length of the blade. A convenient size for the individual bench and for ordinary use has a blade 6" long. It is also well to have in the shop one large one with a 12" blade.
| Fig. 200. Try-Square. | Fig. 201. Miter-Square. | Fig. 202. Sliding-T Bevel. |
In testing the squareness of work with the try-square, care must be taken to see that the head rests firmly against the surface from which the test is made, and then slipped down till the blade touches the edge being tested, Fig. 203. The edge should be tested at a number of places in the same way: that is, it should not be slid along the piece. The try-square is also of great use in scribing lines across boards, Fig. 204. A good method is to put the point of the knife at the beginning of the desired line, slide the square, along until it touches the knife-edge; then, resting the head of the square firmly against the edge, draw the knife along, pressing it lightly against the blade, holding it perpendicularly. To prevent the knife from running away from the blade of the try-square, turn its edge slightly towards the blade.
Fig. 203. Using the Try-Square.
Fig. 204. Scribing with Knife by Try-Square.
The miter-square, Fig. 201, is a try-square fixed at an angle of 45°.
The sliding T bevel, Fig. 202, has a blade adjustable to any angle. It may be set either from a sample line, drawn on the wood, from a given line on a protractor, from drawing triangles, from the graduations on a framing square, or in other ways. It is used similarly to the T-square.
| Fig. 200. Try-Square. | Fig. 201. Miter-Square. | Fig. 202. Sliding-T Bevel. |
Winding-sticks, Fig. 205, consist of a pair of straight strips of exactly the same width thruout. They are used to find out whether there is any twist or "wind" in a board. This is done by placing them parallel to each other, one at one end of the board, and the other at the other end. By sighting across them, one can readily see whether the board be twisted or not, Fig. 206. The blades of two framing-squares may be used in the same manner.
Fig. 205. Winding-Sticks, 12 inches Long.
Fig. 206. Method of Using the Winding-Sticks.
Compasses or dividers, Fig. 207, consist of two legs turning on a joint, and having sharpened points. A convenient form is the wing divider which can be accurately adjusted by set-screws. A pencil can be substituted for the removable point. They are used for describing circles and arcs, for spacing, for measuring, for subdividing distances, and for scribing. In scribing a line parallel with a given outline, one leg follows the given edge, or outline, and the point of the other, marks the desired line. Used in this way they are very convenient for marking out chamfers, especially on curved edges, a sharp pencil being substituted for the steel point.
The beam-compass, Fig. 208, consists of two trammel-points running on a beam which may be made of any convenient length. It is used for describing large circles. A pencil may be attached to one point.
Calipers, outside and inside, Figs. 209, 210, are necessary for the accurate gaging of diameters, as in wood-turning.
| 207 | 208 | 209 | 210 |
Fig. 207. Winged Dividers. Fig. 208. Beam-Compass or Trammel Points. Fig. 209. Outside Calipers. Fig. 210. Inside Calipers. |
The marking-gage, Fig. 211, consists of a head or block sliding on a beam or bar, to which it is fixed by means of a set-screw. On the face of the head is a brass shoe to keep the face from wearing. Projecting thru the beam is a steel spur or point, which should be filed to a flat, sharp edge, a little rounded and sharpened on the edge toward which the gage is to be moved, Fig. 212. It should project about ⅛" from the beam. If the spur be at all out of place, as it is likely to be, the graduations on a beam will be unreliable. Hence it is best to neglect them entirely when setting the gage and always to measure with the rule from the head to the spur, Fig. 213.
Fig. 211. Marking-Gage.
Fig. 212. Spur of Marking-Gage.
Fig. 213. Setting a Marking-Gage.
In use the beam should be tilted forward, so as to slide on its corner, Fig. 214. In this way the depth of the gage line can be regulated. Ordinarily, the finer the line the better. The head must always be kept firmly pressed against the edge of the wood so that the spur will not run or jump away from its desired course. Care should also be taken, except in rough pieces, to run gage lines no farther than is necessary for the sake of the appearance of the finished work. To secure accuracy, all gaging on the surface of wood, should be done from the "working face" or "working edge."
Fig. 214. Using the Marking-Gage.
It is sometimes advisable, as in laying out chamfers, not to mark their edges with a marking-gage, because the marks will show after the chamfer is planed off. A pencil mark should be made instead. For this purpose a pencil-gage may be made by removing the spur of a marking-gage, and boring in its place a hole to receive a pencil stub with a blunt point, or a small notch may be cut in the back end of the beam, in which a pencil point is held while the gage is worked as usual except that its position is reversed. For work requiring less care, the pencil may be held in the manner usual in writing, the middle finger serving as a guide, or a pair of pencil compasses may be used, one leg serving as a guide. A special gage is made for gaging curved lines, Fig. 215.
Fig. 215. Marking-Gage for Curves.
The cutting-gage, Fig. 216, is similar to a marking-gage, except that it has a knife-point inserted instead of a spur. It is very useful in cutting up soft, thin wood even as thick as ¼".
Fig. 216. Cutting-Gage.
The slitting-gage is used in a similar way, but is larger and has a handle.
The mortise-gage, Fig. 217, is a marking-gage with two spurs, with which two parallel lines can be drawn at once, as in laying out mortises. One form is made entirely of steel having, instead of spurs, discs with sharpened edges.
Fig. 217. Roller Mortise-Gage.
The scratch-awl, Fig. 218, has a long, slender point which is useful not only for marking lines, but for centering.
Fig. 218. Scratch-Awl.
The auger-bit-gage, Fig. 219, is a convenient tool for measuring the depth of holes bored, but for ordinary purposes a block of wood sawn to the proper length thru which a hole is bored, is a satisfactory substitute.
Fig. 219. Auger-Bit-Gage.
Screw- and wire-gages, Fig. 220, are useful in measuring the lengths and sizes of screws and wire when fitting or ordering.
Fig. 220. Screw- and Wire-Gages. a. Screw-Gage. b. Wire-Gage. c. Twist-Drill-Gage.
The spirit-level, and the plumb-line which it has largely replaced, are in constant use in carpentering, but are rarely needed in shopwork.
Blackboard compasses, triangles, etc., are convenient accessories in a woodworking classroom.
8. SHARPENING TOOLS.
The grindstone for woodworking tools is best when rather fine and soft. The grinding surface should be straight and never concave. The stone should run as true as possible. It can be made true by using a piece of 1" gas pipe as a truing tool held against the stone when run dry. Power grindstones usually have truing devices attached to them, Fig. 221. A common form is a hardened steel screw, the thread of which, in working across the face of the grindstone, as they both revolve, shears off the face of the stone. The surface should always be wet when in use both to carry off the particles of stone and steel, and thus preserve the cutting quality of the stone, and to keep the tool cool, as otherwise, its temper would be drawn, which would show by its turning blue. But a grindstone should never stand in water or it would rot.
It is well to have the waste from the grindstone empty into a cisternlike box under it, Fig. 221. In this box the sediment will settle while the water overflows from it into the drain. Without such a box, the sediment will be carried into and may clog the drain. The box is to be emptied occasionally, before the sediment overflows.
Fig. 221. Power Grindstone.
In order that the tool may be ground accurately, there are various devices for holding it firmly and steadily against the stone. A good one is shown in Figs. 221 and 222. This device is constructed as follows: A board A is made 2" thick, 6" wide, and long enough when in position to reach from the floor to a point above the level of the top of the stone. It is beveled at the lower end so as to rest snugly against a cleat nailed down at the proper place on the floor. The board is held in place by a loop of iron, B, which hooks into the holes in the trough of the grindstone. In the board a series of holes (say 1" in diameter) are bored. These run parallel to the floor when the board is in place, and receive the end of the tool-holder. The tool-holder consists of four parts: (1) a strip C, 1½" thick, and as wide as the widest plane-bit to be ground. The forward end is beveled on one side; the back end is rounded to fit the holes in the main board A. Its length is determined by the distance from the edge of the tool being ground to the most convenient hole in A, into which the rear end is to be inserted. It is better to use as high a hole as convenient, so that as the grindstone wears down, the stick will still be serviceable; (2) a strip, D, of the same width as A and ⅞" thick, and 15" to 18" long; (3) a cleat, E, ⅝" × ¾", nailed across D; (4) a rectangular loop of wrought iron or brass, F, which passes around the farther end of the two strips, C and D, and is fastened loosely to D by staples or screws.
Fig. 222. Grinding Device.
Fig. 223. Holder for Grinding Chisels or Plane-Bits.
The tool to be ground slips between this loop and the strip C, and is held firmly in place by the pressure applied to the back end of D, which thus acts as a lever on the fulcrum E.
Any desired bevel may be obtained on the tool to be sharpened, by choosing the proper hole in A for the back end of C or by adjusting the tool forward or backward in the clamp. As much pressure may be put on the tool as the driving belt will stand without slipping off.
A still simpler holder for the plane-bit only, is a strip of wood 1½" thick and 2" wide, cut in the shape G shown in Fig. 223. The plane-bit fits into the saw-kerf K, and in grinding is easily held firmly in place by the hand. By inserting the rear end of the stick G into a higher or lower hole in the board A, any desired angle may be obtained. G is shown in position in Fig. 221.
All such devices necessitate a perfectly true stone. The essential features are, to have a rigid support against which the tool may be pushed by the revolving stone, to hold the tool at a fixed angle which may be adjusted, and to press the tool against the stone with considerable pressure. The wheel should revolve toward the edge which is being ground, for two reasons. It is easier to hold the tool steadily thus, and the danger of producing a wire edge is lessened. The edge as it becomes thin, tends to spring away from the stone and this tendency is aggravated if the stone revolves away from the edge. If the stone does not run true and there is a consequent danger of digging into the stone with the tool which is being sharpened, the stone would better revolve away from the edge. The grinding should continue until the ground surface reaches the cutting edge and there is no bright line left along the edge. If the grinding is continued beyond this point, nothing is gained, and a heavy wire edge will be formed.
Fig. 224. Agacite Grinder.
A very convenient and inexpensive grinding tool, Fig. 224, sold as the "Agacite grinder,"7 has a number of different shaped grinding stones made chiefly of carborundum.
Footnote 7: Made by the Empire Implement Co., Albany, N. Y.
The oilstone. After grinding, edge tools need whetting. This is done on the whetstone, or oilstone. The best natural stones are found near Hot Springs, Arkansas. The fine white ones are called Arkansas stones, and the coarser ones Washita stones. The latter are better for ordinary woodworking tools. The India oilstone, an artificial stone, Fig. 77, [p. 58], cuts even more quickly than the natural stones. It is made in several grades of coarseness. The medium grade is recommended for ordinary shop use. Oil is used on oilstones for the same purpose as water on a grindstone. When an oilstone becomes hollow or uneven by use, it may be trued by rubbing it on a flat board covered with sharp sand, or on sandpaper tacked over a block of wood.
Slipstones, Fig. 225, are small oilstones, made into various shapes in order to fit different tools, as gouges, the bits of molding-planes, etc.
Fig. 225. Slipstone.
Files are used for sharpening saws, augers, scrapers, etc. See above, [p. 90].
9. CLEANING TOOLS.
The bench duster. One may be noted hanging on the bench shown in Fig. 166, [p. 98]. Bristle brushes for cleaning the benches are essential if the shop is to be kept tidy.
Buffer. Wherever a lathe or other convenient revolving shaft is available, a buffer made of many thicknesses of cotton cloth is very valuable for polishing tools. The addition of a little tripoli greatly facilitates the cleaning.
WOOD HAND TOOLS.—Continued.
References:*
(4) Scraping Tools.
Barnard, pp. 136-142.
Wheeler, pp. 465, 473.
Griffith, pp. 71-75.
Selden, pp. 149, 177, 182.
Hodgson, I, pp. 61-74.
(5) Pounding Tools.
Barnard, pp. 24-47.
Sickels, p. 70.
Wheeler, pp. 414, 428-432.
Selden, pp. 31, 111, 156.
Goss, p. 60.
Barter, p. 128.
(6) Punching Tools.
Barnard, p. 29.
Wheeler, p. 433.
Selden, p. 161.
(7) Gripping Tools.
For holding work:
Goss, p. 63.
Wheeler, pp. 65-75, 475.
Selden, pp. 140, 147, 186, 194.
Hammacher, pp. 286-291.
For holding other tools:
Goss, pp. 56-59.
Selden, p. 143.
(8) Measuring and Marking Tools.
Goss, pp. 9-20.
Griffith, pp. 9-19.
Hodgson, The Steel Square.
Wheeler, p. 465.
Tate, pp. 21-25.
Building Trades Pocketbook, pp. 234-237.
Selden, pp. 149, 150-152, 175.
Sargent's Steel Squares.
(9) Sharpening Tools.
Barnard, pp. 136-142.
Sickels, pp. 80-85.
Wheeler, pp. 480-488.
Selden, pp. 153, 162, 172, 180.
Goss, pp. 39, 64-69.
* For general bibliography see [p. 4.]