US 3893238 A
A hand operated tool for cutting relatively heavy paper and plasticized wall coverings, cork, carpet and like materials. A cutting blade is held by a manually engageable holder in bi-angular relation to the plane of the material to be cut. As the tool advances along a desired cutting line, the material is severed in a plane disposed in acute angular relationship to the plane of the material. The effect of this provides an undercut edge on the material whereby such edge may be arranged in overlapping relationship with a matingly angulated edge of adjacent material to produce a seamless butt joint. The blade cooperates with an underlying guide shoe and material guiding means in making the angulated cut. Inversion of the tool presents a second knife edge for cutting the material at matching angles in those instances where the guide shoe cannot be employed.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Scholl 1 BUTT SEAM CUTTING TOOL  Inventor: Albert S. Scholl, 2706 S. Kedvale,
Chicago, 111. 60623 221 Filed: Nov. 2, 1973 21 App]. No.: 412,188
 U.S. Cl. 30/294; 30/287; 30/289  Int. Cl. B26B 3/08; B2613 29/02  Field of Search 30/294, 293, 289, 29l, 30/286, 287, 290
 References Cited UNITED STATES PATENTS 2,025,305 12/1935 Parzer 30/286 2,044,426 6/1936 Gelleff 30/293 2,067,986 1/1937 Schmidt 30/287 X 2,238,678 4/1941 Cook 30/294 2,603,866 7/1952 Rice .1 30/335 X 2,806,283 9/1957 Brennan..... 30/335 X 3,178,812 4/1965 Lurie 30/289 X FOREIGN PATENTS OR APPLICATIONS 566,233 l2/l944 United Kingdom 30/294 50,952 4/1910 Switzerland 30/294 1,343,561 10/1963 France 4 1 30/293 146,889 4/1936 Austria 30/293 [451 July 8,1975
Primary Examiner-Al Lawrence Smith Assistant ExaminerJ. T. Zatarga Attorney, Agent, or FirmMcCaleb, Lucas and Brugman [5 7 ABSTRACT A hand operated tool for cutting relatively heavy paper and plasticized wall coverings, cork, carpet and like materials. A cutting blade is held by a manually engageable holder in bi-angular relation to the plane of the material to be cut. As the tool advances along a desired cutting line, the material is severed in a plane disposed in acute angular relationship to the plane of the material. The effect of this provides an undercut edge on the material whereby such edge may be arranged in overlapping relationship with a matingly angulated edge of adjacent material to produce a seamless butt joint. The blade cooperates with an underlying guide shoe and material guiding means in making the angulated cut. Inversion of the tool presents a second knife edge for cutting the material at matching angles in those instances where the guide shoe cannot be employed.
2 Claims, 9 Drawing Figures BUTT SEAM CUTTING TOOL BACKGROUND OF THE INVENTION Under present practice. butt seams for heavy gauge wall covering materials, by way of example, are usually made by cutting the material normal or at right angles to the material face or plane. This is generally accomplished by means of a straight edge, guiding a razor blade knife. In some instances a so-called shoe knife is used. Such a tool has a guide shoe that rides underneath the material and means for holding a knife blade in a plane normal to the material and in subtending angularity so that one lower corner of the knife edge passes through the material and into a clearance slot formed in the guide shoe. By pushing such a tool along a desired line of cut. one or more layers of material may be severed with matching edges formed substantially at right angles to the plane of the material.
In both of the foregoing outlined practices. the right angular edges of the material are adapted to abut one another in forming a butt seam between adjacent wall covering sheets. In the case of wall coverings having a dark colored facing, in particular, such right angular abutted edges usually exhibit an unsightly gap or line of abutment, clue, principally to the light colored backing layer of the material and the inexactness of matching edges at the line of abutment therebetween. Conse quently present practices produce butt seams which are quite noticeable to the eye.
In recognition of the above outlined problems and difficulties experienced in the known art and the almost impossible task of providing seamless or non-visible butt joints under present known practices, particularly with wall coverings having a dark facing color or background, the present invention has been developed to provide an improved tool capable of effecting seamless edges between adjacent material pieces or sheets. Specifically, the tool of this invention provides an undercut edge on the material which is formed at an angle to the plane of the material so that adjacent edges may overlap in effecting a butt seam. Consequently, the finished butt seam is quite invisible even under careful inspection. While the utility of the improved tool of this in vention is especially apparent when working with dark colored wall covering materials, its principles and advantages apply equally in cutting cork. carpet, grasscloth, canvas, plasticized wall coverings and like materials.
SUMMARY OF THE INVENTION In brief. the present invention is directed to an improved combination of elements for a hand operated cutting tool comprising, a planar body member angularly affixed to a planar guide shoe and having a manually engageable handle means mounted thereon. A cutting blade bolder is provided on the body member for removably mounting a multiple edge cutting blade in coplanar relation with the body member and in biangular intersecting relation with the guide shoe. Guide means are provided for guiding materials over the guide shoe and against one of the cutting edges in the normal operating position for the tool. Additional guide means are provided adjacent the second cutting edge for operation of the tool in inverted position whereby the second cutting edge may be aligned with a straight edge for effecting a matching angulated cutting of the material.
An important object of this invention is to provide an improved tool for severing wall covering materials and the like whereby severed edges thereof may be abuttingly overlapped in effecting a relatively invisible butt joint or seam between adjacent material pieces.
Another important object of this invention to provide an improved cutting tool for severing wall covering materials and the like having a dual edge cutting blade and guide means for effectively severing such materials at a predetermined angle of cut with respect to the plane of the material by operation of either of the cutting edges.
Still another object of this invention is to provide an improved cutting tool having a replaceable cutting blade held in bi-angular disposition with respect to material to be severed thereby.
Having thus described the present invention, the above and further object features and advantages thereof will be recognized from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS In the drawings:
FIG. I is a perspective view of the improved tool of this invention showing the major elements thereof except for the handle means;
FIG. 2 is exploded perspective view showing the various elements of the improved tool of this invention;
FIG. 3 is a side elevational view of the assembled tool;
FIG. 4 is a cross-sectional view thereof taken substantially at vantage line 44 in FIG. 3 and looking in the direction of the arrows thereon.
FIG. 5 is an enlarged end elevational view illustrating the overlapping relationship of abutting edges for materials severed by a tool of this invention;
FIG. 6 is an enlarged partial view in cross-section and elevation taken substantially from vantage line 6-6 of FIG. 3 and looking in the direction of the arrows thereon;
FIG. 7 is a perspective illustration of an auxiliary tool employed for mounting and removing cutting blades;
FIG. 8 is a perspective view illustrating the operation of the tool of this invention in its inverted position; and
FIG. 9 is an enlarged cross-sectional view illustrating the guide means associated with the inverted operating position for the tool as viewed substantially from vantage line 9-9 of FIG. I and looking in the direction of the arrows thereon.
DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the particulars and details of the preferred embodiment illustrated in the drawings, initial reference is made to FIGS. I, 2 and 3. As therein shown, the preferred tool of this invention, indicated generally by numeral 15, comprises a main body member I6 adapted to support a handle member I7 and a blade holder IS. A cutting blade I9 is mounted in the holder 18 to angularly subtend therefrom so that one cutting edge thereof intersects the plane of a planar guide shoe 20 affixed to the main body I6 and carrying guide means 21 to operate with the handle member in guiding material past the cutting edge of the blade I9 in operation.
As best shown in FIG. 2 of the drawings, the body member I6 is formed as a unitary metal stamping of generally planar configuration with minor exceptions as will be hereinafter pointed out. The body member has a central planar body portion 26 having an elon gated generally rectangular tail portion 27 tending angularly outwardly from one upper marginal corner thereof for interfitting engagement with the handle member 17. In similar fashion, extending angularly outwardly of the opposite upper corner of the body POI" tion 26, is an elongated arm portion 28, the outer end of which, as indicated at 29, is formed at an angle or bias to the longitudinal axis of portion 28 to interfit with the blade holder 18, as will be described in greater detail hereinafter. A stop shoulder 30 is formed at the junction of the base end of the arm portion 28 and body portion 26. In the particular embodiment illustrated in FIG. 2, such shoulder 30 is disposed at right angles to the longitudinal axis of arm portion 28. Alternately, shoulder 30 may be disposed at an angle to such longitudinal axis (see the dotted line indication at 300 in FIG. 2). In still other instances, depending on the blade 19 employed, shoulder 30 may be located at 3012, again as illustrated in dotted lines in FIG. 2. Below the shoulder, the lefthand lateral margin of the body portion 26 as seen in FIGS. 1, 2 and 3, is formed as a curvilinear edge 31. Preferably, the curvilinear edge 31 is rounded over or formed by angularly intersecting edge surfaces so as to provide a means for engaging the material to be cut and separating the same to clear the body portion 26. Along the bottom edge 32 of body portion 26 is a projecting ear portion 33 of substantially rectangular configuration. Ear portion 33 acts as a mounting means for affixing the body portion to the guide shoe 20 in assembly. Importantly, ear portion 33 is formed out of the plane of body portion 26 and preferably at an angle B of substantially 45 with respect thereto. Similarly edge 32 is formed in a plane at 45 angularity with respect to the plane of body portion 26 to meet the upper face of shoe 20 in assembly (see FIG. 6).
The righthand lateral marginal edge 34 of body portion 26 is distinguished by a pair of parallel spaced rectangular notches or slots 35 and 36, the former being at the base of tail portion 27 where the same intersects the margin 34 of body portion 26, while notch or slotted opening 36 is disposed between slot 35 and the lower angulated edge 32 of the body portion 26.
As best shown in FIG. 2 of the drawings, the handle member 17 is formed by a short length of generally cylindrical metal tubing having an angular bend intermediate its ends. The front or leading end of the handle, as indicated at 40, is cut at an angle with respect to the longitudinal axis of a first cylindrical portion 41 of the handle member.
The upper side of portion 41 is formed with an elongated slotted opening 42 through which the upper margin on edge of the body member 16 extends in certain of the operating positions for the handle member 17 as will appear in greater detail hereinafter. On the bottom side of the cylindrical portion 41 an additional or second slotted opening 43 is provided (see FIG. 2) for clearing the main body portion 26 in positioning of the handle on member 16. Opening 43 registers with opening 42, but is shorter in length. As will be best appreciated from FIG. 3, the mounting of the handle member 17 on body member ]6 involves insertion of tail portion 27 of the latter into the hollow interior of the handle member so that the cylindrical portion 4] embraces the body member l6, with portions of the handle beyond the terminal end 44 of the lower slotted opening 43 engaging one of the positioning notches 35 or 36 as the case may be. Preferably a bicycle type grip of rubber or like material, indicated generally at 45 is mounted over the exterior of the metal handle member 17 to provide convenient manual engagement thereof. To that end. the grip 45 is preferably provided with spaced finger grip indentations 46, 46 on one side which are particularly useful in the inverted operating position of the tool, as will appear hereinafter.
Mounted over the arm portion 28 of the body member is the blade holder 18. As shown best in FIGS. I and 3 of the drawings, the blade holder [8 comprises a reentrantly folded metal member of substantially U- shape cross-section (see FIG. 4) having opposed upper wall portions 50, 51 disposed generally parallel to one another and interconnected by an integrally related folded upper edge margin 52 therebetween; the two wall portions 50, 5] closely embrace the arm portion 28 therebetween when the holder member 18 is mounted on the latter. Spot welds 53, or other fastening means are employed to rigidly affix the holder member 18 to the arm portion 28.
In addition to the upper wall portions 50, 51, the holder member 18 includes a pair of parallel spaced lower wall portions 54 and 55 (see FIG. 4) separated sufficiently to receive and frictionally hold the blade member 19 therebetween. It will be noted that each of the wall portions 54 and 55 is provided with an inwardly turned lower edge portion 54a and a pair of spaced dentent identations 56, which project inwardly of the space between wall portions 54, 55 to actively engage and lock the blade 19 in position therebetween. The holder edge portions 54a serve to guide the covering materials past the blade 19.
Importantly, the outer ends of the wall portions 50, SI and 54, 55 are formed or cut at an acute downwardly sloping angle relative to the longitudinal axis of the holder member 18 with the end edges 57 and 58 thereof being beveled inwardly at substantially 45 to act as a guide means for engaging a straight edge in the inverted operating position for tool 15, as will be ampli fied hereinafter (see FIG. 9).
Mounted on and protruding from the exterior faces of the wall portions 50, 51, 54 and S5 of the blade holder are a plurality of outwardly projecting pairs of locating beads 60, 6] and 62 which are spaced from one another and aligned in registeringly opposed pairs on opposite exterior walls of the holder member. As illustrated in FIG. 3, such bead projections 60-62 are adapted to engage the inner and outer walls of the bandle portion 41 adjacent the outer tip end thereof in its several operating positions. Specifically, as shown in that figure, it will be recognized that the uppermost bead projections 60, 60 limit the upper position for the handle, as shown in full lines therein, by engaging the exterior wall of the handles cylinder portion 41, immediately adjacent the outer tip end thereof and on opposite sides of the slotted opening 42 therein. At the same time the beads 61 underengage the inside walls of the cylindrical portion 41 opposite its areas of engagement with projections 60. These projections in conjunction with the upper locating slot 35 of the body member serve to frictionally hold or wedge the handle member in a first or upper operating position. In similar fashion when the handle member is engaged with the lower notched opening 36 of the body member, the outer tip end thereof is interfitted between the adjacent bead projections 61, 62 on opposite sides of the holder memher, as indicated by the dotted line showing for the handle member in FIG. 3. This variation in the positioning of the handle member serves to accommodate materials of different thickness with the lower exterior portions of the handles cylindrical portion 4I acting as a guide means for directing the material past the knife tool as the latter effects its cut. In this respect it will be readily appreciated that in the upper positioning of the handle member 17 whereat the same is engaged between the beads 60, 6I and with the upper locating notch or slot 35, the line of flow for materials past the knife blade I9 is substantially in accordance with the dot dash line F in FIG. 3.
The cutting blade 19, is best illustrated in FIG. 2 of the drawings showing blade I9 and two modified versions 19a and 19b of a multiple edge cutting blade. As shown in FIGS. 1 and 2. blade 19 comprises a planar blade body 64 made of surgical steel or the like and provided with an elongated slotted opening 65 disposed substantially medially of its length and extending up wardly toward the upper margin thereof. A reentrantly formed reinforcing backing member 66 is folded to fit snugly over the upper margin of the blade body 64 and is affixed thereto as by spot welds 67, at least two of which weld zones are indented and opposite the detent projections 56 of the blade holder for cooperating engagement therewith in the mounted position of the blade in the holder. The lefthand or leading edge 68 of the blade comprises a first angularly ground cutting edge which intersects with a second cutting edge 69 formed along the bottom margin of the blade body 64. It will be noted that the back member 66 is cut or chamfered at one end to coincide with the cutting edge 68 in the specific form of blade indicated at 19 in FIGS. 1 and 2.
As best illustrated in FIGS. I and 3, blade 19 is adapted to fit between the wall portions 54 and 55 of the holder 18, with the rearward end 70 of the blade backing member abuttingly engaging shoulder 30 of the holder body and the intersection of the two cutting edges 68 and 69 thereon projecting forwardly of the holder member. Inasmuch as the arm portion 28 on the holder body is formed to diverge upwardly at an angle with respect to the horizontal in an upright position for the tools body member I6, it will be appreciated immediately from an examination of FIG. 3 that the blade I9 is held by the holder at an angle to the horizontal so that one lower corner of cutting edge 69 thereon inter sects the plane of the guide shoe 20.
The modified blade 19a as illustrated in FIGS. 2 and 7, differs from blade 19 principally in that the same is doubled-ended or, that is, comprises three cutting edges 68a. 69a and 71a; cutting edges 68a and 71a being disposed at an angle to the bottom linear cutting edge 69a to permit reversal or reversed positioning of the blade in the holder 18. It will be noted that the backing member 66a, which is affixed to the upper margin of the blade body 64a, has ends formed at right angles to its longitudinal axis and located beyond the angularly disposed cutting edges 68a and 710. In utiilizing the blade 19a the shoulder position 30a on the tools body portion 26 is employed to abuttingly engage and locate the ends of the backing member 660 in the holder.
The second modified blade I91) illustrated in FIG. 2 is substantially identical to blade [90 with the exception that the backing member 66b thereon has its ends chamfered or cut at an angle to conform to the angular disposition of the end cutting edges 68!: and HI). Shoulder 30b of the tools body portion 26 serves to locate blade 19b in the holder. Basically it will be recognized that the formation of the two modified blades 19a and I9!) is such that the body portions theeof are formed substantially as trapezoids. It further will be appreciated that each of the blades is adapted to be frictionally received between the wall portions 54 and 55 of the holder member and that the detent indentions 56 in such walls cooperate with the spaced depressions of indentations 67 formed in the backing members of the respective blades as above mentioned, thus resiliently locking the blades in mounted position in the holder.
As previously noted, the disposition of a blade in the holder is such that one lower corner of cutting edge 69 intersects the plane of the guide shoe 20 when the latter is assembled with the main body member 16. As will be noticed best from an examination of FIGS. 1 and 2 in particular, the guide shoe 20 comprises a generally elongated planar body portion 72 rounded over at its ends 73 and 74. The leading or front end 74 of the shoe body 72 is curvilinear and chamfered at an angle to the main plane of its formation to provide an entry or nose portion for the leading edge of the shoe to assist its movement beneath material to be cut. A first elongated opening 75 is formed generally on the longitudinal center line of the body portion 72 to accommodate the passage of the intersecting blade I9.
Mounted directly over the slotted opening 75 is a first guide means 21 comprising a bifurcated leaf spring having a slotted opening 78 extending inwardly of one end thereof and a mounting platform portion 79 at its opposite end. Portion 79 is configured to fit register ingly over the nose end 74 of the guide shoe body portion 72. Spring means 2] is held to the upper face of the end portion 74 by an overdisposed mounting plate 80 which is spot welded to the body portion 72. The arms of the leaf spring guide angle upwardly from the guide shoe to assist the feeding of the material across the cutting edge 69 of the blade 19, as best shown in FIG. 3 of the drawings. The slotted opening 78 in the guide means 21 of course accommodates passage of the cutting blade 19 therethrough and into the underlying clearance opening 75 of the guide shoe.
As noted previously, the guide shoe is adapted to be affixed to the bottom margin of the body member I6 by inserting the projection portion 33 on the latter into a registeringly aligned slotted opening 81 formed through the guide shoe body portion 72. It will be recognized that opening 81 is slightly off center so that when assembled with the body member I6, the plane of the blade means will align with the central axis of the clearance opening 75. Inasmuch as the portion 33 of the body member 16 is formed at 45 or thereabouts with respect to the plane of the body portion 26, mounting of the latter on the shoe member disposes the plane of the body portion as well as the cutting blade at an angle B of substantially 45 with respect to the guide shoe. This relationship is best illustrated in FIG. 6 of the drawings. Once assembled the guide shoe is af fixed to the body portion 26 as by brazing or welding to provide a rigid fixed connection between the guide shoe and the body member 16.
As thus described, it will be understood that the tool of this invention is particularly distinguished by virtue of the fact that the cutting blade 19 thereof is held in bi-angular relationship to the guide shoe 20, that is to say, a first attack angle labeled A in FIG. 3 disposes the blade at an angle to the line of advance of the shoe so as to gradually infeed the material to be cut across the cutting edge 69 thereof. Simultaneously the plane of the blade 19 is held at approximately 45 to the plane of the guide shoe 20 or at an angle B as illustrated in FIG. 6. With this bi-angular arrangement of the blade, it will be understood that material 85 is severed or cut as a bias or angle to the plane of the material's formation, thus lapping edge portions 86 and 87 at adjacent edges of the material are provided to permit a substantially seamless butt junction therebetween. It further will be appreciated that the two matching edges 86 and 87 of adjacent material pieces conveniently may be produced by overlapping two pieces and simultaneous cutting the same along the desired out line in the manner illustrated in FIG. 4. In any event, the intermatching 45 faces of the bias cut edges 86 and 87 effectively overlap in assembly with little or none of the backing color, such as in layer 88 (FIGS. 5 and 9) readily visible at the junction of the outer layer 89 of the material, even when cutting wall covering materials having a dark background. for example.
In considering the operation of the present invention, its method of effecting a desired overlapping butt joint is as above described and illustrated in FIG. 4 of the drawings. It will be appreciated, however, that in cutting adjacent sheets or lengths of the wall covering materials mounted in overlapping fashion, production of a seamless butt joint therebetween, in the normal operating position of the tool 15, can be effected except for the positions of the tool whereat the guide shoe 20 interferes with adjacent walls, molding, etc. This would occur, as, for example, at the base line of the room adjacent baseboards, and at the ceiling line adjacent the ceiling wall. Stated another way, where obstructions prevent the passage or movement of the guide shoe sufficiently to permit the cutting edge of the knife blade to move through the material, completion of the cut must be made in some other fashion. To accommodate this problem inverted positioning of the tool is contemplated and for this purpose the second cutting edge 68 on blade 19 is utilized. As will be noted best from FIG. 3, with the blade 19 mounted in a holder 18, cutting edge 68 projects at an obtuse angle with respect to leading edges 57 and 58 ofthe holder means. By inverting the tool or that is turning the same upside down in the manner illustrated in FIG. 8 ofthe drawings, cutting edge 68 is available and may be inserted through the material as at the ceiling of the room to complete the unfinished cut barred by the presence of the guide shoe 2]. In accomplishing this, it is essential that the angle of the cut match the line of severance between the materials previously made by the normal cutting position of the tool. To this end with the tool of this invention inverted, a straight edge, such as the blade of a wide scraper 90 (see FIG. 9), may be placed parallel to the desired line of cut and one or the other of the two 45 undercut edge surfaces 57 or 58 guided thereagainst to dispose the tool at a 45 with respect to the plane of the material. By drawing the knife downwardly from the 8 ceiling line then the overlapping edge formation may be completed. In a similar fashion completion of the cut at or near the base line of the wall may be effected, bearing in mind that the tool may be disposed with either surfaces 57 or 58 of the holder engaging the straight edge for guidance.
Inasmuch as it is fully contemplated that the blade means 19 and its modified forms will be resiliently held in the holder by means of the cooperating detent inden tations 56 and the depressions 67 of the holder and blade, respectively, it has been found convenient to provide a tool to assist in the insertion and removal of the blade. To this end the tool as illustrated in FIG. 7 is provided having a generally cylindrical manually engageable handle portion 96 with an opening 97 near one end for hanging convenience and including a generally flat, key-shaped blade 98 extending from one end of the handle 96. The blade 98 enters the central slotted opening 65 of the blade body in the manner indicated in FIG. 7. By pushing sideways on the blade the tool permits a safe injection or rejection of the blade into and out of the holder 18.
From the foregoing it is believed that those familiar with the art will readily understand and appreciate the unique features and operational advantages provided by the improved tool of this invention and while the same has been described in association with a particular preferred embodiment as comprising the best mode presently contemplated to enable those skilled in the art to practice the invention, it will be appreciated nevertheless that the concepts and features involved therein may depart from the specifics described hereinabove without materially departing from its inventive purview.
I. A hand operated tool for cutting angulated butt seam edges in wall covering materials and the like comprising: an elongated planar guide shoe formed with an opening therethrough and having a bottom planar guide surface engageable with an underlying wall to guide the tool in its normal operating position, a generally planar body member affixed to said guide shoe adjacent one end thereof such that the plane of said body member lies in acute angular relation to the plane of said guide shoe and guide surface, an elongated arm portion formed on said body member in overhanging spaced alignment with the longitudinal axis of said guide shoe and opening such that the longitudinal axis of said arm portion intersects the plane of said guide shoe and guide surface; holder means affixed to said arm portion and comprising a pair of parallel spaced wall portions for slidably receiving and holding a cutting blade in the plane of said body member, a cutting blade frictionally mounted in said holder means and having a first cutting edge in the plane of said body member and parallel to the longitudinal axis of said arm portion to subtend in bi-angular intersecting relationship with the plane of said guide surface, said cutting edge invading said opening rearwardly of the leading other end of said guide shoe to interferingly engage sheet materials passing over the latter, whereby movement of the tool through said material serves to feed material over the leading end of said guide shoe and against said cutting edge to sever the same in a plane disposed in acute angular relationship to the formational plane of said sheet material. a secondary cutting edge formed on a lateral margin of said blade, in intersecting relationship with said first cutting edge and adapted for use in an inverted operating position for the tool, and additional guide means formed on the outer end of said holder means for locating the second cutting edge in a plane of angularity coincident with the plane of severance effected by said first cutting edge.
2. A hand operated tool for cutting angulated butt seam edges in wall covering materials and the like comprising: an elongated planar guide shoe formed with an opening therethrough and having a bottom planar guide surface engageable with an underlying wall to guide the tool in its normal operating position, a generally planar body member affixed to said guide shoe adjacent one end thereof such that the plane of said body member lies in acute angular relation to the plane of said guide shoe and guide surface, an elongated arm portion formed on said body member in overhanging spaced alignment with the longitudinal axis of said guide shoe and opening, such that the longitudinal axis of said arm portion intersects the plane of said guide shoe and guide surface; holder means affixed to said arm portion and comprising a pair of parallel spaced wall portions for slidably receiving and holding a cutting blade in the plane of said body member, handle means removably mounted on said body member in angular disposition to said holder means and guide shoe spaced means on said body member and holder means for adjustably mounting and holding said handle means in selected positions of elevation relative to said guide shoe, and a cutting blade frictionally mounted in said holder means and having a first cutting edge in the plane of said body member and parallel to the longitudinal axis of said arm portion to subtend in bi-angular intersecting relationship with the plane of said guide surface, said cutting edge invading said opening rearwardly of the leading other end of said guide shoe to interferingly engage sheet materials passing over the latter, whereby movement of the tool through said material serves to feed material over the leading end of said guide shoe, against said cutting edge and between said handle means and guide shoe to sever the same in a plane disposed in acute angular relationship to the formational plane of said sheet material.