Drilling Tools And Their

A few tools for drilling holes in metal will enable a farmer to make many handy appliances and to make many repairs on his machinery and equipment that would otherwise be impossible.

DRILLING EQUIPMENT FOR THE FARM SHOP

215. Drilling Machines,—The post drill is probably the best drilling machine or tool for general work inside the shop. It is especially good for drilling holes of the larger sizes—above in. in diameter. A power-

driven post drill may be desirable under some conditions, although it is not hard work to turn the drill by hand, especially if the drill bits are kept sharp.

The carpenter's brace can be used for drilling holes in iron and steel. For holes about in. in diameter, it works very well but is somewhat slow for holes of larger size. Small drills are easily broken in a brace if the workman is not careful. * The chain drill, used with the carpenter's brace, raaketf a very effective drilling combination. Holes can be drilled much faster and easier than with the brace alone. With a chain drill the workman does not have to push hard against the brace, as the pressure for drilling is supplied by simply turning a knob. The chain drill can be used in the shop, or it can be taken to the machine shed or the field. Thus a hole may be drilled in a machine or implement with-Fig. 190—The post drill is an out having to take it, or a part of it, to a farm12pPiCi0 0f eQuit>ment for the sh°p- Chain drills are available with either automatic or plain hand feeds. The plain-feed drills are cheaper and for farm shop use are practically, if not altogether, as good.

The hand drill is one of the most useful tools for drilling small holes in lightweight metal and in wood. For the farm shop, one that takes drills up to l/i in. in diameter is large enough. (See Art. 66, page 51.)

Fig. 191.—The chain drill ia good for drilling hole« in part» of machines and implements when it is not convenient to take the6e parts to the shop, as well as for drilling in tho 4 shop.

Fio. 192.—Tho hand drill ia one di the most useful toot* for drilling small holes, either in metal or wood.

Breast Drill Machine Art Photos

The breast drill ia an excellent tool where elec ts similar to tho tricky id available, hand drill but is larger.

The breast drill is very much like the hand drill, except that it is larger and pressure can be applied by leaning against it. Although a useful tool, it is not greatly needed in the farm shop. A hand drill works just as well or even better for small holes, and a chain drill or a post drill works better on drills larger than y^ in. in size.

The electric drill is an excellent tool where electricity is available. It is somewhat expensive, however, for most farm shops.

216. Twist-drill Bits.—Twist drills arc available in two qualities— carbon-steel drills and high-speed drills. The high-speed drills stay sharp longer but cost considerably more. Carbon-steel drills are usually quite satisfactory for the farm shop, particularly if they are kept sharp.

Kiruls of Shanks.—Twist drills are available in various kinds of shanks, the following being the most common:

1. Bit stock or square toper to fit a carpenter's brace.

2. Straight round shank.

3. Blacksmith's drill shank (straight round with one flat side).

4. Morse taper (round taper with a flat tang on end).

Bit-stock drills are held in two-jaw chucks like those on the carpenter's brace. They are a little harder to center in the chuck than the straight round-shank drills, which are held in three-jaw chucks. The flat-sided blacksmith's drills are held in special chucks furnished on post drills. Some of these chucks have flat-sided holes or sockets to receive the drills, and a drill must be inserted with its flat-side against the flat side of the hole. To keep the drill from falling out of the chuck a setscrew is tightened against the drill. The setscrew does not keep the drill from slipping around in a rotary direction in this kind of chuck, however, for this is done by the flat-sided socket of the chuck. Drills with Morse taper shanks are made mostly in the larger sizes. They are used in machine shops

B. Straight round anc* are usually not found in farm shops, «hank drill. 217. Sizes of Drills for the Farm Shop.—A

(straight 'round"hank with set of ranging by sixty-fourths or by thirty-

flat «deK ^ ^ seconds from 3-ie to in., and a set ranging by or«; taper t n . gi^^hs from to % in. would meet most of the drilling needs on an average farm. The small set would be useful in drilling holes in sheet metal for rivets and screws, for drilling out old rivets, and for drilling holes in wood for wood screws. The larger set would be adequate for drilling holes for most bolts and rods. If a post drill is available, it would be well to have two or three drills larger than yi in., possibly %_> and 1 in.

Otter Sizes of Drills.—Small drills are available in sets with the sizes designated by letters from A to Z, and by wire-gage numbers from 1 to 80. These two systems

Fig. 195.—Types of drill bits classified according to kind of shanks:

simply give finer graduation in sizes than the fractional-inch system, the wire-gage system having 80 drills graded in size from 0.228 to 0.0135 in., and the letter system having 26 different, sizes ranging from 0.234 to 0.413 in. These drills are commonly used by machinists and by jewelers and would seldom be needed in a farm shop.

218. Drill Chucks.—Drilling tools and machines may be purchased with different lands of chucks for holding the drills. Breast drills, hand drills, and electric drills are commonly furnished with three-jaw chucks for taking straight round-shank drills. The carpenter's brace has a two-jaw chuck that takes the square taper shank. Chain drills may be purchased with either type of chuck. Post drills take blacksmith's drill bits with flat-sided round shanks.

In order to use different styles of drill bits in different machines, adapting chucks are used. For instance, a small three-jaw chuck that has a square taper shank may be used in a carpenter's brace to hold straight round-shank drills. Likewise, adapting chucks are available for holding straight round-shank bits, or for using square taper shank bite in a post drill (see Fig. 196).

219. Taper reamers are valuable for enlarging holes. They are especially useful in assembling machinery when boltholes in iron

A. Thrce-jivw chuck to fit into a post drill and hold straight, round-shank drills.

Threc-jaw chuck to fit into a carpenter's brace and hold straight round-shank drills-C\ Chuck to fit into a post drill and hold bit-Mock drills. Fia. 197.—Taper reamers are valuable ior enlarging holes in metal.

or steel parts do not quite line up. A few turns with a taper reamer will usually allow the bolt to go in. Taper reamers are commonly made with square taper shanks and are used in the carpenter's brace.

220- Suggested Set of Drilling Equipment.—The following suggestive list of drilling equipment would make an excellent assortment for the farm shop:

1 past drill with automatic feed. 1 set of blacksmith's drill bite for post drill (K, Ks, K, Hi HI

1 three-jaw chuck to hold straight round-shank bits in post drill. 1 chuck to hold bit-stock drills in post drill. 1 carpenter's brace, 10-in. sweep, ratchet type.

1 set bit-stock drills (K> Ks, H, M)> 1 chain drill, plain hand feed, with two-jaw chuck to hold bit-stock drills. 1 h;ind drill, three-jaw chuck to hold straight round-shank drills up to H 1 set straight round-shank drills (Hst H, %2t Me, X)-

. DRILLING HOLES IN METAL

221. A Properly Sharpened Drill Essential.—A properly sharpened drill is the first requirement for satisfactory drilling. A drill that is not properly ground will require excessive effort- to use it; it will cut slowly; it will do poor work; and there will be danger of breaking it. Drills that are used much require frequent grinding. Any one who expects to use drills with satisfaction or profit to himself, should therefore become proficient in grinding them. See page 10*1 for information on drill sharpening.

Fio. 198.—A drill should be started in h deep center-punch mark.

A, The point of the center punch can be placed easily in the desired location by steadying the band against the work.

B. Once the center punch is correctly placed, strike one or two light taps to get the direction of striking and then follow with one or two firm, well-directed hlows.

222. Center Punching.—A twist drill should be started in a deep center-punch mark—one that is big enough to take the point of the drill.

Otherwise, the drill will likely "wander" and drill the hole off center or not exactly in the right place. For accurate work, the location of the hole should first be marked by the intersection of two scratch lines made with a scriber or scratch awl and a square. In the case of small rectangular pieces, the center can be located by drawing diagonals. A very satis-

Fig. 199.—In the event a punch mark is not properly located, it may be changed by driving the punch at an angle, as at A% or it may bo hammered out with a ball-peeu hammer, ius at Bt and a new one made. 8till another method ia to turn the bar over and make a punch mark and drill from the other aide.

factory scriber can be made by grinding the end of an old saw file to a needle point.

The crossing point of the two lines is first marked by a light dot made with a sharp center punch. If upon inspection it is found that the dot is exactly in the right place, then a large, deep punch mark is made and the drilling can proceed. In case the dot is not properly located, however, it should be shifted by driving the punch at an angle or it may be hammered out with a ball-peen hammer and a new punch mark made.

Centre Punch Angle

Fig. 199.—In the event a punch mark is not properly located, it may be changed by driving the punch at an angle, as at A% or it may bo hammered out with a ball-peeu hammer, ius at Bt and a new one made. 8till another method ia to turn the bar over and make a punch mark and drill from the other aide.

223. Lubricant for Drills.—When drilling in mild steel, the drill should be lubricated with lard oil or a threading oil. Turpentine or kerosene is recommended for drilling hard steel or other very hard materials. Drills may be used in cast iron or brass without a lubricant, although many mechanics prefer to use lard oil. Ordinary lard, when melted, makes a good lubricant for drills and other cutting tools.

A lubricant helps to cool the drill, and it makes it cut easier and smoother. If a good lubricant Is used, the drill will stay sharp longer.

A squirt can of lard oil or threading oil should therefore be kept handy when drilling is done.

224. Holding Work on Drill Table; Safety in Drilling.—When using a power drill, the piece being drilled should be clamped or otherwise firmly held on the drill table or platen. If it is not, the drill may catch and throw the piece off the table, possibly breaking the drill or injuring the operator or both. A method sometimes used to hold small pieces is to bolt a board to the drill table and then drive nails in the board to keep the piece from turning.

WThen drilling with a hand-driven post drilVthe work may be held on the drill table by hand if it is long and a firm hold can be secured. Holding small pieces by hand, even on a hand-driven drill, is not safe.

Fig. 200.—It is a good plan to 225. Preventing Drill Breakage.— clamp the work to the drill table. Most drill breakage occurs just as the drill goes through the piece being drilled. To prevent such breakage the piece should be securely held, and the pressure on the feed should be lightened just as the drill goes through. Turning the drill at a higher speed will also help.

In case a drill gouges and catches just as it starts through and there is difficulty getting the hole finished, the trouble can usually be overcome by turning the work over and drilling from the other side.

226. Drilling Holes through Round Rods.—In drilling a hole in a rod, there is a tendency for it to roll on the drill table, increasing the danger of breakage and making it difficult to get the hole drilled straight through on a diameter. To keep the rod from rolling, it may be placed in a

Lubricate the drill with lard oil or threading oil when drilling in steel.

V-notch sawed in the surface of a two-by-four or a two-by-six block. A deep center-punch mark, of course, should be made to start the drill.

Fio. 201.—A V-notch sawed in a block of wood ¡9 useful for holdiug round rods or pinea while holes are being drilled in them.

Fio. 201.—A V-notch sawed in a block of wood ¡9 useful for holdiug round rods or pinea while holes are being drilled in them.

227. Drilling Large Holes.—Where large holes are to be drilled, it is generally easier to drill through first with a small drill, and then follow it with a drill of the desired size. Where extreme accuracy is required in locating a large hole, a small hole is sometimes drilled through first to serve as a pilot for keeping the large drill centered.

Fio. "202.—Enlarging a hole with a r*jwiirmftn's tftper reamer.

If a drill of the desired size is not available and if a slightly tapered hole will do, a hole may be drilled first somewhat smaller than the desired size, and then enlarged with a taper reamer.

228. Speeds for Drills.—If a post drill or other drill is to be driven by power, one should know the desired speed for the drill bit, in order that suitable sizes of pulleys, gears, etc., may be used. For general drilling in mild steel with carbon-steel drills, a peripheral speed of about 30 to 35 ft. per minute gives good results. {The peripheral speed of a drill is the speed of a point on the periphery or outside edge of the drill.) Higher speeds can be used for drilling cast iron and brass.

The peripheral speed of a drill, in feet per minute, is found by multiplying its diameter in inches by 3.1416, dividing by 12, and multiplying by the revolutions per minute the drill turns. Table IV gives revolutions per minute required for different sizes of drills to give a peripheral speed of 30 ft. per minute. It will be noted that small drills need to run very fast, and large ones very slow.

Table IV.—Revolutions per Mivote Rjoqcirkd for Various Sizes op Drills to Give a Peripheral Speed of 30 Ft., per Minutk Diameter of Drill, K.p.m. to Give

Inches 30 Ft. per Minute

Yic 1833

H 917

K 45S

Me 367

Vi6 262

m 229

1 115

In drilling small holes by hand, the drill should be turned as fast as possible without letting it wobble. Wobbling, of course, increases the danger of drill breakage.

Power-driven post drills are often driven too fast for drilling large holes. In cases where they cannot be driven slowly enough by power, it is frequently better and practically as easy to turn the drill by hand. If a drill is driven too fast, the cutting lips have a tendency to slide over the metal instead of cutting into it. There is also danger of overheating the drill and drawing its temper.

229. Drilling Holes in Thin Metal.—There is a tendency for a drill to gouge and to catch when drilling thin metal. This can be prevented by placing the metal between two pieces of hardwood and drilling through wood, metal and all.

230. Countersinking can frequently be done to advantage in riveting and in making holes to receive flat-headed wood screws. Countersinking can best be done with a regular countersinking tool, although very good work can be done with a twist drill. A drill ground at the regular angles will not countersink a hole at quite the right angle for a flat-headed wood screw. Quite acceptable work can be done, however, by using a drill just a little larger than the diameter of the screw head and drilling just deep enough for the drill to cut a full-diameter hole.

An old drill too short for regular drilling can be ground to make a very good countersink. The cutting lips should be ground at an angle of about 40 to 45 deg. with the central axis of the drill, instead of the usual angle of 59 deg.

Fig. 203.—Holes may be drilled easily ia thin metal by clamping it between two pieces of wood and drilling through both wood and metal.

Practical Points on Drilling

1. A properly sharpened drill is the first requirement for satisfactory work.

2. Always insert the drill carefully in the chuck.

3. Do not allow the drill to slip in the chuck, as it will damage both the drill and the chuck.

4. Start the drill in a large, deep, center-punch mark accurately located.

o. Use lard oil or a threading oil when drilling in steel.

6. In drilling a large hole, a small drill may be used first, followed by a drill of the desired size.

7. Securely fasten the work to the drill table when using a power drill.

8. A block of wood on the drill table prevents drilling holes into the table.

9. Use lighter pressure just as the drill goes through, and run the drill faster if possible. This lessens danger of drill breakage.

10. Large drills can be turned too faat for good work.

11. »Small drills work best when turned faat.

12. An old drill ground with the cutting lips at about 40 to 45 deg. with the axis of the drill, instead of the usual angle of 59 deg., makes a good countersink.

13. A taper reamer is valuable in enlarging holes, and in reaming out holes in machine parts that do not line up.

14. To keep round rods from rolling on the drill table, lay them in a V-notch cut in a wooden block.

Questions

215. (a) What drilling machines or tools would you recommend for the farm shop? (b) What are the particular advantages and limitations of the post drill? The carpenter's brace? The chain drill? The hand drill?

216« (a)What kinds or qualities of twist drills are available? (6) What kinds of shanks are available on twist drills? (c) What are the advantages and disadvantages of the various kinds of shanks?

217. (a) What is the eomroon system of designating sizes of twist drills? (6) What other systems are sometimes used? (c) What si2es of twist drills would be desirable for the farm shop?

218. (a) What kinds of drills are held in two-jaw chucks? In three-jaw chucks? (6) What kind of chucks do post drills usually have? (c) How may round-shank drills be used in the carpenter's brace? (d) How may round-shank drills, or bit-stock drills, be used in a post drill that has a chuck to hold blacksmith's drills?

219. Of what particular use are taper reamers in the farm shop?

220. Make a list of drills and drilling equipment you would recommend for the farm shop.

221. Besides cutting slowly, what other troubles or difficulties may arise from using a dull drill?

222. (a) Why should a large center-punch mark always be used for starting a twist drill? (6) Outline a procedure for getting the punch mark located exactly right. (c) In case it is found that the punch mark is not properly located, what would you recommend?

223. (a) Why are lubricants used when drilling most metals? (b) What materials may be used as lubricants? <c) What metals require no lubricant« when being drilled?

224. (a) How may the work being drilled be fastened to the drill tablo? (6) What troubles may occur if the work is not securely fastened on a power-driven drill? (c) Under what conditions is it not neccssary to fasten the work to the table of a hand-operated post drill?

225. (a) What precautions should be taken to prevent drills from catching just as they go through the work? (6) In the event a drill gouges and catches just as it starts through, what would you recommend?

226. (a) What difficulties may be encountered in drilling holes through round rods? (ib) How may these troubles be avoided?

227. (a) What advantage is there in drilling a small hole firet and following through with a large drill, when a large hole is to be made? (b) Under what conditions may a large bole be made by first drilling a small hole and then enlarging it with a taper reamer?

228. (a) What is meant by the peripheral speed of a drill? (6) What is a desirable peripheral speed for general drilling in mild steel? (<c) How fast should a hand drill or other haud-operated tool be turned in drilling small holes? (d) What difficulties may be encountered if a drill is driven too fast?

229. (a) What difficulties are likely to be encountered in drilling thin metal? (b) How may these difficulties be avoided?

230. How may twist drills be used for countersinking holes in metal in case a special tool is not available?

References

Bo3S, Dext, and White: "Mechanical Training."

Robhl: "Farmer's Shop Book."

Van Lkuvbn: "Cold Metal Work."

Tostisok and Kranzusch: "Metalwork Essentials."

Radebaugh: "Repairing Farm Machinery and Equipment."

Burohardt: "Machine Tool Operation." Part I.

Sharp and Sharp: "Principles of Farm Mechanics."

CHAPTER XV

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.

Get My Free Ebook


Post a comment