US 2811878 A
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N V- 1957 A. J. MORGAN, JR 2,811,878
TOOLS FOR MAKING SLOTS IN METAL BY USE OF A DRILL Filed Oct. 1, 1954 r} I 28 5 9 W nun-mm 27 V 'y ,1 I A 1 WJHIWIZ V//////////////if" L IN V EN TOR.
nited States Patent Office 2,811,878 Patented Nov. 5, 1957 TGULS FOR MAKING SLOTS IN METAL BY USE OF A DRILL Adolphus J. Morgan, Jr., Norfolk, Va.
Application October 1, 1954, Serial No. 459,683
1 Claim. (Cl. 77-62) The present invention relates to tools for making slots with a drill and methods of making slots and is particularly concerned with improved methods and devices by means of which circular apertures may be elongated into slots.
It often happens in the installation of some part of the machinery that the holes which are provided for the passage of a bolt on the frame or other part are found to be out of alignment with the holes on another part or element to be attached thereto. The amount of this misalignment is usually such that the holes overlap; and it would be found impossible to guide an ordinary drill by means of the usual chuck or drill press because the drill would slide sidewise into the hole which is already there.
Another occasion when it becomes desirable to enlarge a hole into a slot occurs when it is desirable to have a slot for the purpose of adjustment, such as the tightening of a belt.
One of the objects of the invention is the provision of improved methods of elongating apertures into slots and the provision of improved tools by means of which elongated apertures of any desired size may be made, using an ordinary drill bit.
Another object of the invention is the provision of an improved tool for guiding a drill bit relative to an existing hole for the purpose of elongating that hole, which tool is adapted to be manufactured economically and used for a long period of time in making elongated slots.
Another object is the provision of improved tools of the class which are durable, accurate in their guiding function, which utilize the drill most effectively, and which are adapted to enlarge holes in spite of-obstructions which are located nearby.
Another object of the invention is the provision of improved tools for making elongated slots or apertures of various shapes in various materials, such as metal, wood, plastics, stone, concrete, masonry, etc.
Another object of the invention is the provision of improved tools for making slots, which tools may be used with ordinary rotating drills, as well as reciprocating hammer drills, and core drills.
Other objects and advantages of the invention'will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.
Referring to the single sheet of drawings accompanying this specification,
Fig. 1 is a fragmentary view in perspective, showing the important parts of a tool embodying the invention in inverted position;
Fig. 2 is a top plan view of an assembly utilizing such atool;
Fig. 3 is a fragmentary sectional view, taken on the plane of the line 3 -3 of Fig. 2, looking in the direction of the arrows;
Fig. 4 is a view in perspective of a modification adapted to be mounted in a holder made similar to an ordinary die holder;
Fig. 5 is a fragmentary plan view of a work piece which is in the course of being provided with an elongated slot using such a tool, in which the crescent guiding lug is of less thickness than the radius of the hole;
Fig. 6 is a fragmentary plan view of a work piece in the course of being provided with an elongated slot with such a tool, the crescent guiding lug of the tool having a thickness which is greater than the radius of the hole;
Fig. 7 is a diagram showing how a single hole may be elongated by means of a drill and one of my tools to any desired length;
Fig. 8 is another diagram showing how an arcuate slot may be made by utilizing the present tool.
Referring to Figs. 1 to 4, the most important parts of the tool embodying the invention are exemplified in these figures, in which the tool of Fig. 1 is indicated in its entirety by the numeral 19.
The tool 10 preferably includes a flat body 11, which may be of any desired shape, and is made flat so that its upper and lower plane sides 12 and 13 may engage clamping members and the work piece, respectively. The tool 10 is thus made out of a bar of suitable metal, such as steel, which is hardened and tempered after being properly shaped so that it will resist wear and guide the drill with a minimum amount of friction.
A different tool it is employed for each different size of hole; and my invention contemplates a complete set of tools for drills of different sizes, the number of tools depending upon the number of different size of holes which are to be accommodated. For example, a tool kit of such devices might include tools for A inch, inch, A inch, inch, and additional sizes up to A, the sizes differing by inch in each case.
Another kit of tools embodying my invention might have the devices arranged for drills of different sizes according to a decimal scale.
The tool ill is provided with a through bore 14, which is the same size as the drill that is intended to be used; and the through bore 14 is arranged accurately at right angles to the top 12 and bottom 13 of the tool.
The tool 10 is provided on one of its sides, top, or bottom with a guide lug 15 preferably of crescent shape and formed with an inner concave wall 16 and an outer convex wall 17.
The outer convex wall 17 of the crescent lug 15 is cylindrical and formed on a radius which is equal to the radius of the through bore 14 so that this convex wall 17 will fit in the hole that has already been made. The inner concave wall 16 is formed on an equal radius and on a center, which is the center or axis of the bore 14.
Thus the concave wall 16 of the crescent lug 15 forms a prolongation of the bore 14; and the crescent lug is adapted to fit in the aperture which is to be elongated because the lug is formed on the same size radius.
The thickness of the body 11 of the tool may be such as is suitable to guide the drill; and tools to fit the same holder would have the same thickness. 1 would prefer a certain thickness for a certain range of holes to be elongated; and a holder would be provided to fit each of these ranges. For example, one holder would accommodate sizes /8", A1, having thicknesses of another holder would accommodate sizes /8, /2, and having thicknesses of Thus the tools for smaller apertures have lesser thickness than the tools for larger apertures.
The length of the crescent lug 15 may also depend upon the size of the hole'and on the thickness of the work piece, but is not limited by the thickness of the work piece, since the work piece may be backed up by a table or bed 18, which has an aperture 19, into which the crescent lug can project, if it is longer than the thickness of the work piece.
The thickness of the crescent lug from the inner wall 16 to the outer Wall 17 may also be varied, depending on the question whether the tool is to be used with soft materials to elongate a hole quickly or to be used on harder materials, involving more frequent drilling and slower progress.
I prefer to make the thickness of the crescent lug less than the radius of the hole, differing from this radius by something more than the web of the drill. The pattern made with such a tool in making a slot is shown in Fig. 5, where the crescent lug walls may be defined by the curves 20 and 21, when the lug is inserted into the aperture 22.
When the crescent lug is made thicker, as shown at 23 in Fig. 7, it should preferably be made thicker than half the diameter of the hole plus the web of the drill. The reason for having the crescent lug thinner, as shown in Fig. 5, or thicker, as shown in Fig. 6, is that no drill cuts efficiently at the center; and the most eificient cutting is done by that part of the drill which extends outward from the web to the periphery.
The reason for having the crescent thicker than the holes radius would be primarily to gain more slot length per drilling, but the drills center must pass through the work piece. The thickness in this case should be greater by something more than the web of the drill in order to avoid having the chisel edge center of the drill fall at the very edge of the hole, where it would be in position for the flat side of the chisel edge to strike the edge of the hole and give a vibration or chattering.
As both of the walls 16 and 17 of the crescent are curved on the same radius, it will be understood that the crescent will always extend over more than half of the bore 14; that is, the horns 24 and 25 of the crescent always extend beyond a diametrical line.
Even when the crescent is thin, as shown in Fig. 5, the horns 24 and 25 of the crescent are shown to extend around more than half of the periphery of the hole 22. This means that when the crescent is slid into the hole that has already been made, such as the hole 22, the crescent fits this hole and extends around more than half of the periphery so that the tool cannot be translated. It can, however, be rotated, and is held in fixed position by any suitable means, such as a C clamp, part of which is indicated at 26 in Fig. 3.
Referring to Figs. 2 and 3, these figures show a setup utilizing a tool embodying my invention, indicated at 10a. This tool 10a is for a certain size of drill and differs from the tool 10 of Fig. 1 in that it has a crescent lug 15a and 15b at both ends. The crescent lug 15a extends from the bottom of the tool 10a, while the crescent lug 15b extends from the top of the tool 10a; V
and they are located adjacent the holes 14a and 15b.
Only one of these lugs is used for guiding the drill at one time; but the lugs 15a and 15b are located on opposite sides of the holes 14a and 14b relative to the end of the tool. For example, the left end of the tool in Fig. 2 is indicated at 27; and the hole 14 is adjacent the end 27; but the crescent lug 15a is located in alignment with that wall of the hole 14a which is away from the end 27.
This means that the drill 28 can be used with the tool in the hole 14a to enlarge the hole 29 in the work piece 30 toward the left in Fig. 3.
The lug 15b is located on the side of the hole 14b toward the end 31 of the tool 10a. Thus, if the tool 10a were inverted in Fig. 3, the lug 15b would be located close to the end 31; and it would permit the enlargement of the hole 29 in a direction toward the right of Fig. 3.
The question why the crescent lug is on the side toward the end of the tool or why it is away from the end of the tool becomes important when there are obstructions to the location of the body of the tool on the work. Thus the tool 10a may utilize either of its lugs 15a or 15b, depending on obstructions on the work piece.
For the purpose of preventing rotation of the tool on the work piece, the tool may be provided with apertures 32 or 33 registering with apertures 34 or 35 in the work piece 30 for receiving a dowel pin when the tool is not held by a clamp. Such apertures and pins are not used when a multiplicity of holes are to be used side by side, as shown in Figs. 5 to 8 because they would involve the use of a multiplicity of separate holes in the work piece as the tool progresses from one position to another.
The tool 10 of Fig. 1 may be simply clamped in place with its lug 15 in the hole 29 of the work piece 30 by means of a C clamp 26. Then the drill 28 will be guided by the hole 14, to enlarge the hole 29 after the manner shown in Figs. 5 or 6.
With the tool 10a of Fig. 3 a tool holder 36 is preferably employed. The tool holder 36 preferably comprises a bar of metal which has an elongated hole 37 with portions 38', 39, 40, and 41 of different width for receiving crescent lugs 15 of different size on tools for holes of different size.
The elongated hole 37 is located to receive the upwardly extending crescent lug 15b, which is then used with the tool holder to prevent rotation of the tool about the lug 15a, which is currently being used. The tool holder 36 has a depending lug 42 at its right end, which is as long as the thickness of the tool 10a to maintain the parallelism of the tool holder, the tool, and the work piece 30.
The tool holder 36 also preferably has a cylindrical bore 43 at its end opposite to the lug 42 for receiving a cylindrical lug 44, which is fixedly secured in the holder and in the tool bore 45 by friction or by a pin 46.
Lug 44 is so located on the tool holder and the length of the tool holder and tool are such that the upwardly extending crescent lug 15b comes into engagement with both sides of the elongated aperture 37 at the width 38, 39, 40 or 41 which is appropriate for that size of tool.
Referring to Fig. 4, in this tool the body is circular and has a cylindrical outer wall 47 provided with a plurality of conical depressions 48. This tool has the same bore 146 and the depending crescent lug 15c at one side of the bore. Such a cylindrical tool may be mounted in a holder similar to an ordinary die holder and secured in place by a set screw of the holder extending into one of the conical depressions 48.
The tool 110 is rotated in the die holder and secured with its depending crescent lug 15c extending oppositely to the direction in which the hole is to be elongated.
Referring to Fig. 5, this pattern shows the elongation of a hole 22 toward the right by means of a tool, the crescent lug of which is thinner than the radius of the hole by the amount of the web of the drill.
With the thinner crescent lug the successive holes are closer together; and the ridges between them, which are located at 24a and 25a in Fig. 5, are less pronounced. It requires less additional work with a file to straighten out the opposites edges of the slot.
Referring to Fig. 6, this shows the pattern of an elongated slot made with a tool having a crescent lug that is wider or thicker than the radius of the hole. In this case less drilling operations are involved; but the intermediate ridges at 24b and 25b, for example, are more pronounced; and more labor is required to file them off.
Fig. 7 shows how a single small tool of the type shown in Fig. 1 may be used to guide the drill for making an elongated slot.
Fig. 8 shows the pattern of an elongated slot which is arcuate because the tool has been pivoted about a center, indicated at C, as the lug is moved from one position to another.
My method of elongating holes or forming slots comprises the drilling or formation of the first hole of predetermined size and the formation of a guiding tool having a crescent lug formed on radii equal to that of the hole.
The tool is provided with a hole which borders the crescent lug on the inside, which hole is of the same diameter as the hole to be enlarged. The crescent lug is inserted into the first hole; and the tool is held in place, with the tool and hole overlapping the work piece at the edge of the hole that is to be enlarged. A drill is then inserted in the hole of the tool and is guided by the tool while the drill is driven until it makes another hole, which communicates with the first one.
If the slot is to be made longer, the crescent lug is then moved into the scalloped formations of the second hole; and further holes are successively drilled until the Slot is as long as desired.
The tool is then removed and the scallops along the side of the elongated slot are removed by means of a file or small grinding tool.
It will thus be observed that I have invented an improved tool for use in making elongated slots with a drill. My tool is simple in construction and may be used over and over again for a long period of time.
Holes which are out of alignment can be enlarged in the right direction so as to bring parts of them into alignment by merely using my tool with a drill. In the same way elongated holes may be provided for permitting adjustment of one part relative to another.
The present tools may also be used for making slots or grooves in stone, concrete, or masonry where a straight shank masonry drill may be employed rather than a conventional twist drill. For example, a drill which is known on the market as the Rawldrill may be used with a hand hammer, electric hammer, or pneumatic hammer, the drill being held by a chuck and twisted back and forth as it is reciprocated, due to the blows of the hammer.
In such case the tool may be clamped to a bar of channel iron, which is anchored to the floor, or a short length of lumber may be held against the side of the tool to hold it in position when it cannot be anchored.
In addition to the foregoing, the tool may be used with masonry drills, such as are known under the name Koredrills. These are cylindrical and hollow like a tube or pipe and provided with teeth of hard material, such as tungsten carbide mounted around the end of the cylinder to enable it to cut a hole in masonry.
The Koredrill is rotated by a conventional electric drill motor having a chuck for holding its shank.
It will thus be observed that my tools are equally adaptable for guiding rotating and reciprocating drills, the latter being peculiarly adaptable to the drilling of masonry, where they have a crumbling action as distinguished from the shearing action which is involved with metal.
The inwardly extending pointed portions of the work piece which are left along the edge of the slot may be readily chiseled away, whether they are long or short; and thus a thicker crescent may be used for guiding masonry drills.
While I have illustrated a preferred embodiment of my invention, many modifications may be made Without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claim.
Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:
A drill press assembly for providing a work piece with an elongated slot by using the drill bit, comprising a bed for supporting a flat work piece, a jig comprising a flat body, a dowel pin carried thereby, said jig having a bore bordered on its lower side by a depending crescent-shaped lug adapted to fit in a bore of a work piece and locating said jig bore overlapping the body of a work piece adjacent a bore in the work piece, a clamping member comprising a metal plate having a lug adapted to engage a work piece beyond the end of said jig body, said lug being of the same length as the thickness of the jig body, said clamp having a stepped aperture receiving an upwardly extending lug on the jig and said clamping member and jig having aligned apertures with a pin secured therein, and means for clamping said clamp, jig and a workpiece to said bed, so that a drill guided by said jig bore may drill away the overlapped portion of a workpiece to make an elongated slot.
References Cited in the file of this patent UNITED STATES PATENTS 647,133 Emery Apr. 10, 1900 2,674,906 Timpner Apr. 13, 1954 FOREIGN PATENTS 356,942 Great Britain Sept. 17, 1931