Tool Sharpening And Fitting Chapter X Tool Sharpening

Sharp tools arc the mark of a good workman. Only a poor workman or an amateur would struggle along with a dull tool rather than take time to sharpen it. The time required for sharpening is soon repaid in faster and better work.

129. Cutting Edges Composed of Small Teeth.—The cutting edge of a sharp knife or similar tool is composed of a series of small microscopic teeth. Such tools are used with a diagonal or sawlike motion, and the small teeth aid in the cutting. The size of the teeth determines whether the edge is known as coarse or fine. For certain kinds of work, coarse edges are best, and, for other kinds of work, medium, fine, or very fine edges are required. Bread knives, kitchen paring knives, and scythes and grass blades, for example, work better when sharpened to coarse edges, while plane bits and wood chisels need fine edges, and razors still finer edges.

130. General Method of Sharpening.—The general method of sharpening edge tools is to produce first a coarse edge by grinding with a grinding wheel, or by rubbing on a coarse sharpening stone, and then to finish by whetting on the fine side of an oilstone if a fine edge is required. If a very fine edge is desired, the process is carried a step further and the tool is stropped on leather.

With very few exceptions, tools are ground with the grinding wheel turning against the cutting edge. This produces a smaller burr or wire edge. Likewise, in whetting on a stone, the tool is drawn or pushed over the stone with the cutting edge leading; or in case of baek-and-forth motion, more pressure is applied during that portion of the stroke when the cutting edge is leading—not trailing. In stropping on leather, however, the cutting edge must always be trailing.

WOOD CHISELS AND PLANE BITS

When a chisel or plane bit becomes dull, it is first necessary to decide whether it needs grinding or not. If a tool is properly used and cared for,

/ Wrong

/ Right

it can be resharpened many times on the oilstone before it will need regrinding. The tool should be ground if the edge is unusually dull, nicked, or if a slight bevel has been formed on the flat side by careless whetting. The tool should be ground, also, if it does not have the desired angle of bevel, or if the cutting edge is not square with the sides.

131. Grinding Wood Chisels and Plane Bits.—For general work, wood chisels and plane bits are usually ground at. an angle of about 25 to 30 deg. For softwoods, the angle may be somewhat less, and, for hardwoods, somewhat more. The smaller the angle, the easier the tool will cut, but the sooner it will become dull. A good way to check the angle of grindiug is to use. a T-bevel set for the desired angle, or simply grind so that the length of the bevel is a little more than twice the thickness of the blade (see Fig. 105).

The tool may be held against the grinding wheel in ar^ manner that will produce a smooth, even bevel of the desired angle. When using a hand-operated grinder, the work lunit C 2 units*

Fro. 105.—Grinding edge tools.

A. An edge tool should bo ground with a straight or concave bevel—not with a convex be vol.

S. A plane for general-purpose work is usually ground with the corners slightly rounded.

C. For general-purpose work, the length of bevel on a plane bit or wood chisel should be a little more than twice the thickncss of the blade.

Flo. 106.—A good method of holding the tool while grinding. Note that the tool rest is adjusted to give the desired angle of bevel, and that the tool is held firmly against the rest. The tool is moved back and forth sideways aero»« the face of the wheel.

rest should be adjusted so that the tool, when held down firmly against the rest, will come in contact with the wheel at the desired angle.

The tool should be nvyvedfrom side to side across the face of the wheel to insure even grinding and to prevent overheating. A light, yet firm sure should be used to hold the tool against the wheel. The wheel is turned toward the cutting edge, not. away from it, and at a moderately fast, steady speed. The tools should be dipped in water frequently during grinding to prevent overheating.

It is sometimes easier for beginners to hold the tool against the flat side of the wheel rather than against the usual curved grinding surface. If ground on the side of the wheel, a little more care will need to be taken to prevent overheating.

The tool should be checked occasionally as the grinding proceeds, to make sure it is being ground at the desired angle and that the cutting edge is square with the sides. The try square may We used to check for squareness, care being used not to touch the cutting edge against the square (see Fig. 100). The blade of a jack plane should usually be rounded a little at the corners rather than being made perfectly straight all the way across (see Fig. 105B).

Fro. 107.—Both hands oiay b« used to hold the tod when a power grinder is used. Grasp the tool so that, when the first finger of the right hand is against the tool rest the desired ancle o£ bevel will be produced.
Flo. 108.—An edce tool may be ground on the fiat side of the grinding wheel if desired. This produces a smoother job and is usually more easily done than grinding on the curved surface. More care must be used, however, to prevent overheating.

Some mechanics prefer to straighten the edge of a plane bit or chisel, before grinding, by rubbing it on the edge of an oilstone (see Fig. 110).

Grinding should continue until the dull edge is removed, all nicks are removed, and the edge is straight and square and the bevel is of the desired angle. The burr, or wire edge, which is left by grinding, is then removed by whetting on the oilstone. (A wire edge is a thin, rough edge that can be felt with the thumb or finger, or seen in a good light. Also, a wire edge will catch on cloth while a smooth edge will not,)

tool for squareness of Grinding. or wood chiacl may b© straightened Care must be uwd to prevent and squared on the edge of an oilatone. touching %h% sharp against the square.

132. Whetting a Wood Chisel or Plane Bit—If the tool has a good bevel on it and is not nicked, but is simply dull, then it can be quickly sharpened by whetting on an oilstone without first grinding it.

The first step is to whet the beveled side of the tool on a coarse stone or the coarse side of a combination stone. A few drops of light oil, such as motor oil mixed with kerosene, should be used on the stone. The whetting should continue until a slight burr, or wire edge, is produced.

To keep the stone from sliding around when in use, it may be held in a wood vise, or mounted on a small board about 1 by 4 by 10 in. long. Small strips tacked to the board will hold the stone in place.

The heel of the bevel should be raised slightly while whetting. It is a good plan to placc the heel down against the stone and then tilt the tool fonvard until oil is forced from under the front edge; and tilt forward a very little more.

A "figure 8" motion, a circular motion, or a back-and-forth motion may be used. Regardless of the kind of motion, care should be taken to prevent the stone from being worn hollow in the center and to avoid a rocking motion, which would produce a rounded instead of a flat bevel.

133. Whetting on Fine Side of Stone.—After a slight wire edge ha£ been produced by whetting on the coarse side of the stone, or by grinding on a grinding wheel, the next step is to remove the wire edge. This is done by whetting on the fine side of the stone. The tool Is honed or whetted first on the flat side and then on the beveled side. In this operation, two things are most important:

1. Keep ttie 1/>ol perfectly flat against the stone when whetting the flat vide.

2. Use very tight pressure when whetting the beveled side.

If the tool Is not held perfectly flat when whetting the flat side, a small bevel may easily be produced on the flat side, and it would then be

tool for squareness of Grinding. or wood chiacl may b© straightened Care must be uwd to prevent and squared on the edge of an oilatone. touching %h% sharp against the square.

Fio. 110.—The edge of a plane bit impossible to put the edge in good condition without regrinding it. If too heavy pressure is used while whetting the beveled side, the wire edge may be increased instead of decreased.

Fig. 111.—Alter the beveled edge is ground or whetted on the coarse side of the oilstone < the wire edge is then removed by whetting on the fine side of the stone; whetting the tool alternately on the beveled aide and on the flat side. When whetting on the beveled side, raise the heel of the tool slightly and use moderate pressure. When whetting on the flat side, keep the tool perfe<ily fiat against the atone.

Fig. 111.—Alter the beveled edge is ground or whetted on the coarse side of the oilstone < the wire edge is then removed by whetting on the fine side of the stone; whetting the tool alternately on the beveled aide and on the flat side. When whetting on the beveled side, raise the heel of the tool slightly and use moderate pressure. When whetting on the flat side, keep the tool perfe<ily fiat against the atone.

Fig. 112.—a very keen edge may be produced on a tool by finishing on a leather strop.

Use drawing stroke«, stropping first on the beveled side and then on the flat side.

In alternately whetting the flat and the beveled sides, make sure that the wire edge is actually turned back and forth. That is, if the tool is being whetted on the leveled side, be sure that the wire edge Is actually turned from the beveled side to the flat side before reversing the tool for whetting on the flat side.

If the whetting is properly done, the wire edge will quickly become smaller and smaller, and practically disappear. The tool will then be sharp.

Fia. 113.—If a leather strop is not available, an edge tool may be stropped on the palm of the band.

134. Stropping.—Stropping the tool on a piece of smooth leather, after it is whetted on the fine side of the oilstone, will produce an exceptionally fine, keen edge. A few drawing or pulling strokes with the cutting edge trailing, not leading, first on the beveled side and then on the other, is all that is required. If a piece of leather is not available, the tool may be stropped on a piece of smooth wood or even on the palm of the hand. A piece of smooth leather glued to a block of wood about 2 in. wide and 6 in. long makes a good strop.

135. Testing the Edge for Sharpness.—Probably the best way to tell if a tool is sharp—the way used by most mechanics—is to try the edge on the thumb. The blade is grasped in one hand with the fingers around the blade, thumb at the cutting edge, and flat side of blade toward the thumb (see Fig. 114). With very light pressure the ball of the thumb is moved along the edge from side to side. (Do not push against the edge.) If the tool "takes hold" or pulls on the calloused skin, it is sharp; if it does not take hold it is dull and should be resharpened.

Fro. 114.—An excellent way to t«st a blade for sharpness is to try it on the ball of the thumb. Hold the tool firmly and draw the ball of the thumb lightly back and forth over the edge. Do not prext againxt Ih* edan. A sharp tool will "take hold" or pull on the tough cuticle. A dull tool feels smooth and will not "take hold."

Fro. 114.—An excellent way to t«st a blade for sharpness is to try it on the ball of the thumb. Hold the tool firmly and draw the ball of the thumb lightly back and forth over the edge. Do not prext againxt Ih* edan. A sharp tool will "take hold" or pull on the tough cuticle. A dull tool feels smooth and will not "take hold."

Another test is to see if the too) will shave hair from the arm or wrist-It is not too much to expect a tool to shave. With a little practice, a boy should be able to put a shaving edge on a tool.

Some idea of the condition of an edge tool may be obtained by simply /^^^^wk looking at it. If the edge is sharp v^ /M^j it cannot be seen. If it is very dull, \__

the edge will appear as a line or a "p, narrow shiny surface that reflects the //N.

Fio. 115.—A sharp tool will easily shave.

Fig. 116.—Tho edge of a sharp tool cannot bo seen. The edge of a dull tool can be Been as a narrow, bright, shiny line that reflects light. In making this test hold the tool in a good light and move it, about so that reflections from a dull edge may easily be seen.

light. To make this test, the tool must be held in a good light and moved about slightly so the eye can easily see any reflections.

OTHER BEVEL-EDGED TOOLS

Practically all bevel-edged woodcutting tools may be sharpened in the same manner as plane bits and wood chisels.

136. Drawknives.—A drawknife is sharpened in the same manner as a wood chisel or plane bit, except that, in whetting, the stone may be rubbed over the edge, instead of moving the tool back and forth over the stone.

137. Pocket Knives, Butcher Knives, Bread Knives.—If the edge of a knife is quite blunt, or nicked, or not of the desired shape, it should be ground on a griudirtg wheel before whetting on an oilstone. Care should be used not to overheat the tool, by using only light, pressure and dipping it in water frequently. The blade should be lifted occasionally to see that it is being ground at the desired angle.

If the tool is only slightly dull it may be sharpened by whetting on the oilstone. It may be sharpened by whetting altogether on the fine side of the stone, although it can generally be sharpened faster by first whetting on the coarse side, until a fine burr or wire edge is produced,

Fio. 117.—A drawknife is sharpened in the same manner aa a wood or plane bit, except that, in whetting, the stone may be rubbed over the edge of the tool instead of moving the tool back and forth over the atone.

Fio. 118.—In sharpening a pocketknife, raise the back of the knife slightly to keep the cutting edge in contact with the atone. Moderate pressure should be used, and oblique angling strokes should be made, with the cutting odge leading, not trailing.

and then finishing on the fine side. The back of the knife must be raised slightly while whetting to keep the cutting edge in contact with the stone. Moderate pressure is applied, and oblique angling strokes used, with the cutting edge leading—not trailing. An extremely smooth keen edge can be produced by finishing on a leather strop.

Fig. 119.—In grinding knives, the wheel should turn against the cutting edge. Ilold the knife at an angle to the wheel, use moderate pressure, and move it slowly from side to side.

It is not necessary to put a smooth edge on a bread-slicing knife. Many prefer to leave a light wire edge on the blade, as it will cut practically as well and stay sharp longer than if whetted to a smoother edge.

The edge, of a butcher knife can be kept in good cutting condition by using a sharpening steel on it occasionally. The steel does not really sharpen the knife, but simply removes bits of fat and tissue and straightens the microscopic teeth that form the edge.

Fio. 120.—Sharpening an ax. After grinding, a smooth edge may be produced by nibbing ^ - with an oilstone.

138. Axes and Hatchets.—Axes and hatchet« are best sharpened on a fine grinding wheel, care being taken to grind at the desired angle and

Fig. 119.—In grinding knives, the wheel should turn against the cutting edge. Ilold the knife at an angle to the wheel, use moderate pressure, and move it slowly from side to side.

Fio. 120.—Sharpening an ax. After grinding, a smooth edge may be produced by nibbing ^ - with an oilstone.

not to overheat the tools. A thicker edge is needed for splitting than for chopping. After grinding, a keen smooth edge can be produced by rubbing with an oilstone.

139. Scythes and Grass Sickles.—Scythes and grass sickles are easily [ sharpened on a grinding wheel. Such tools do not require keen cutting edges like plane bits and are commonly left with the wire edge on them. A blade should be lifted frequently while grinding to make sure that it is being ground at the original bevel. The grinding is best done by holding the blade at a considerable angle to the grinding wheel (see Fig. 121).

Fig. 121.—Scythes and grass sicklcs arc easily sharpened on a grinding wheel, although they may be sharpened l>v rubbing with a scythe atone or by filing.

Scythes and sickles may also be sharpened by stroking with a scythe stone, or by filing—either plain straight filing or draw filing (see Art. 197). It is a good plan for the workman to keep a scythe stone or file with him when using a scythe or sickle, for resharpening the blade every 20 or 30 min.

140. Mower Sickles.—Mower sickles can best be ground on special grinders made for that purpose. With a little practice and patience, however, mower sickles can be satisfactorily ground on an ordinary wheel. The grinding may be done either on the flat vertical side of such a wheel, or on the regular curved grinding surface.

Two important points should be observed in grinding a mower sickle: (1) grind at the original bevel, and (2) use light or moderate pressure to prevent drawing the temper.

Fig. 121.—Scythes and grass sicklcs arc easily sharpened on a grinding wheel, although they may be sharpened l>v rubbing with a scythe atone or by filing.

Special sickle grinders arc available which hold the sickle in the proper position against the grinding wheel. With such a grinder, it is a simple matter to do a good job of grinding.

Grinding Wheel
Kia. 122.—Mower aickles are ground cwicst on special grinders made for that purpose, although they can be satisfactorily sharpened on an ordinary grinding wheel.

141. Ensilage-cutter Knives,—Ensilage-cutter knives are sharpened by grinding on a grinding wheel, using the precaution of grinding at the

Fig. 123.—Disks and colter« can bc#f. be ground on grinders with attachments to hold tha the disks properly against the grinding whoel.

Fig. 123.—Disks and colter« can bc#f. be ground on grinders with attachments to hold tha the disks properly against the grinding whoel.

original bevel, and with only a moderate pressure to prevent drawing the temper. If there are large nicks, they may be best removed by placing the knife flat on the work rest and moving it back and forth with the cutting edge square against the revolving wheel. The edge is then ground back to the desired bevel.

142. Rolling Colters; Disks.—Many farmers prefer to have their colters and disks .sharpened on a special rolling machine that sharpens the edge of a disk or colter by passing it between large rollers under heavy pressure. Disks and colters may be sharpened on a grinding wheel, however. Some sort of a support to hold the disk in place greatly facilitates the work. Some tool grinders have attachments for property holding disks in place against the wheel.

143. Hoes; Spades; Shovels.—-Such tools as hoes, spades, and shovels are usually best sharpened by plain filing, or by draw filing (see

Ftg. 121.—Iloea, spades, and a hovels are e&aily sharpened, either by plain filing or by draw filing (see Art. 197.)

Ftg. 121.—Iloea, spades, and a hovels are e&aily sharpened, either by plain filing or by draw filing (see Art. 197.)

Alt. 197), care being used to maintain the original angle of bevel. If a vise is not at hand the tool can frequently be held satisfactorily by cramping the handle against a box, a tree, or a fence post.

144. Scissors; Snips.—Scissors or snips ma3r be sharpened by.grinding or filing the beveled edge carefully at the original angle, and then whetting on an oilstone. Some scissors may be too hard to file and can be sharpened only by grinding. If the scissors are not too dull, the beveled edges may be renewed by whetting on an oilstone. After the beveled edges are renewed (by grinding, filing, or whetting), the blades are then smoothed by whetting on the fine side of an oilstone, care being used to keep the blades perfectly flat when whetting the flat side, and at the correct angle when whetting the beveled edge.

146. Wood Auger Bits.—Two important points should be observed in sharpening a wood auger bit:

1. The spurs or scoring nibs must be sharpened by filing on the inside only, so that they will cut a circle of the exact diameter the auger is supposed to bore. If they are sharpened by filing on the outside, they will cut a circle too small and the auger will not feed into the wood. In case the scoring nibs have become bent outward, or have burrs on the outside, they may be dressed lightly on the outside with a small file, keeping it perfectly flat against, the outside of the auger.

2. The cutting lip« should be filed on the top side (the side next to the shank) care being taken to remove the same amoimt of material from each of the two cutting

Fig. 126.—Sctfwors may be sharpened by filing or grinding the beveled edg** and then finishing on the oilstone, alternately whetting the fiat »idt and the beveled edge of each blade.

edges. Filing ou the bottom side would be more likely to change the suction or angle of clearance, as well as to make it more difficult to remove the same amount from each lip.

Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

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

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    What Does A Workman Need To Sharpen A Cutting Tool?
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