Abstract: The guide has a four sided cam, and a face of the cam engages the marginal side edge of a sheet placed on a work table. A square rod is slidably received in an axial opening in the cam, to be clamped in a predetermined position for scoring parallel the sheet edge. The rod is adapted to be inserted in four different orientations, with the result that the scoring tool is located at four different heights above the work table. This geometry sheets of four different thickness to be conveniently scored to a predetermined depth. A second rod holds a second tool suitable for scoring a second material.

Abstract: A thin rectangular blade of flat configuration has its two longer edges rolled or burnished to form alternatively usable sharpened edges. The blade is held in a structure which includes a handle having a concave surface against which the blade is adapted to be clamped by a convex clamping member in order to end the initially flat blade into an arcuate configuration such that the exposed scrapping edge is curved in order to reduce the likelihood that its edge portions will gouge a workpiece or the like. The blade is oriented at an angle with respect to the longitudinal axis of the handle, and the radius of curvature of the bent blade is approximately twice the length of its longer edges. A screw fastener holds the clamping member to the handle and clearance is provided for the reserve, or unused scraper edge of the blade when the blade is so clamped.

Abstract: The internal compressive stresses sub-adjacent the surfaces of relatively thick (over 1/2 inch) glass sheet material are mechanically reduced on the surface to be scored by bending the glass during the scoring process to allow a glass cutting wheel of conventional geometry to overcome these stresses, and thereby produce a fissure in response to conventional levels of applied force. Spaced pressure applying rollers are provided alongside the cutter wheel, and an anvil wheel located below the cutter wheel reacts the bending moment forces so applied. In one version, these pressure rollers are also used to break out the glass in a second pass, with the cutter wheel retracted. In a second version an additional pair of break out rollers is provided downstream of the cutter wheel, and a pair of stress neutralizing pressure rollers act on the underside of the sheet to prevent running of the break back toward the cutter wheel.

Abstract: A flat spring steel element has a handle portion, an offset shank portion, and a blade portion defining a symmetrically ground chisel edge. The edge is oriented at 45.degree. to the handle axis and each end of the chisel edge is ground to define two scoring tips. One of these tips has a 15.degree. forward rake angle when the tool handle is held perpendicular the surface to be scored, and the other tip has a similar rake angle when the tool handle is held at a slightly inclined position relative to such surface.

Abstract: A small anvil is provided below the score line and is resiliently connected to a manually manipulated head above the score line such that the user can push downwardly on the head in order to deflect the sheet material through a desired bend angle along the score line. The head is resiliently supported from a block slidably mounted on an underlying table. The same table also supports the anvil, and the support preferably comprises support rods which extend obliquely inwardly from outside the edge of the sheet so that the head is particularly useful in trimming segments of plastic sheet of less than a foot in longitudinal dimension.

Abstract: Plastic sheet material is scored and broken by a three-step process, either in an automated version or by means of a manual approach. The automated version includes a carriage with a first station having a heated scoring tool, and a backup, or anvil roller, against which the tool can act as a carriage traverses the sheet. A second station in the carriage includes two laterally spaced bending rollers, and another anvil roller which cooperates with these bending rollers to deflect the sheet through a critical bend angle (approximately 4.degree., but less than 6.degree.) to develop a fissure at the score line. A third station in the carriage includes an anvil roller and two more bending rollers for actually breaking the sheet. The manual version utilizes a longitudinally extending bead beneath the score line and a cross slide mounted on guide rails and adapted for movement above the bead, the cross slide carries a scoring tool which includes a handle portion also useable as a sheet cracking device.