A glass cutter is a tool used to make a shallow score in one surface of a piece of glass (normally a flat one) that is to be broken in two pieces, for example to fit a window. The scoring makes a split in the surface of the glass which encourages the glass to break along the score. [1] This is not to be confused with the tools used to make cut glass objects.
Regular, annealed glass can be broken apart this way but not tempered glass as the latter tends to shatter rather than breaking cleanly into two pieces. [2]
In the Middle Ages, glass was cut with a heated and sharply pointed iron rod. The red hot point was drawn along the moistened surface of the glass causing it to snap apart. Fractures created in this way were not very accurate and the rough pieces had to be chipped or "grozed" down to more exact shapes with a hooked tool called a grozing iron.
Between the 14th and 16th centuries, starting in Italy, a diamond-tipped cutter became prevalent which allowed for more precise cutting.
In 1869, the wheel cutter was developed by Samuel Monce of Bristol, Connecticut, which remains the current standard tool for most glass cutting. [3]
A glass cutter may use a diamond to create the split, but more commonly a small cutting wheel made of hardened steel or tungsten carbide 4–6 mm in diameter with a V-shaped profile called a "hone angle" is used. The greater the hone angle of the wheel, the sharper the angle of the V and the thicker the piece of glass it is designed to cut.
The hone angle on most hand-held glass cutters is 120° to 140°, though wheels are made as near-flat as 154° or even 160° [180° would be flat like a roller] for cutting glass as thick as 0.5 inches (13 mm). [4] Their main drawback is that wheels with sharper hone angles will become dull more quickly than their more obtuse counterparts.
The effective cutting of glass also requires a small amount of oil (kerosene is often used) and some glass cutters contain a reservoir of this oil which both lubricates the wheel and prevents it from becoming too hot: as the wheel scores, friction between it and the glass surface briefly generates intense heat, and oil dissipates this efficiently.
When properly lubricated a steel wheel can give a long period of satisfactory service. However, tungsten carbide wheels have been proven to have a significantly longer life than steel wheels and offer greater and more reproducible penetration in scoring as well as easier opening of the scored glass.
The cutter is then rolled firmly over the glass, producing a "score line" or "fissure," weakening the glass along this line. Pressure as light as 5 or 6 pounds, upon a 120 to 140 degree wheel on thin glass; Pressure as heavy as 20+ pounds, with a 154 to 160 degree wheel, on very thick glass. The well-scored pane is ready to be split. The glass may be further weakened by lightly tapping along the cut. The glass cutter in the photo has a ball on one end for tapping the glass. Running pliers may then be used to "run" or "open" to the split.
Glass cutters are manufactured with wheels of varying diameters. [5] One of the most popular has a diameter of 5.5 mm (7⁄32 in). The ratio between the arc of the wheel and the pressure applied with the tool has an important bearing on the degree of penetration. Average hand pressure with this size wheel often gives good results. For a duller wheel on soft glass a larger wheel (e.g., 6 mm (1⁄4 in) will require no change in hand pressure. A smaller wheel (3 mm (1⁄8 in)) is appropriate for cutting patterns and curves since a smaller wheel can follow curved lines without dragging.
General purpose glass is mostly made by the float glass process and is obtainable in thicknesses from 1.5 to 25 mm (1⁄16 to 1 in). Thin float glass tends to cut easily with a sharp cutter. Thicker glass such as 10 mm (3⁄8 in) float glass is significantly more difficult to cut and break; glass with textured or patterned surfaces may demand specialized methods for scoring and opening the cuts.
Large sheets of glass are usually cut with a computer-assisted (CNC) semi-automatic glass cutting table. These sheets are then broken out by hand into the individual sheets of glass (also known as "lites" in the glass industry). [6]
A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, threading and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis.
A machinist is a tradesperson or trained professional who operates machine tools, and has the ability to set up tools such as milling machines, grinders, lathes, and drilling machines.
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflective surface, the process can also involve roughening as in satin, matte or beaded finishes. In short, the ceramics which are used to cut, grind and polish other softer materials are known as abrasives.
Beveled glass is usually made by taking thick glass and creating an angled surface cut (bevel) around the entire periphery. Bevels act as prisms in sunlight creating an interesting color refraction which both highlights the glass work and provides a spectrum of colors which would ordinarily be absent in clear float glass.
A drill bit is a cutting tool used in a drill to remove material to create holes, almost always of circular cross-section. Drill bits come in many sizes and shapes and can create different kinds of holes in many different materials. In order to create holes drill bits are usually attached to a drill, which powers them to cut through the workpiece, typically by rotation. The drill will grasp the upper end of a bit called the shank in the chuck.
A reamer is a type of rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides. There are also non-precision reamers which are used for more basic enlargement of holes or for removing burrs. The process of enlarging the hole is called reaming. There are many different types of reamer and they may be designed for use as a hand tool or in a machine tool, such as a milling machine or drill press.
The phrase speeds and feeds or feeds and speeds refers to two separate velocities in machine tool practice, cutting speed and feed rate. They are often considered as a pair because of their combined effect on the cutting process. Each, however, can also be considered and analyzed in its own right.
A grinding dresser or wheel dresser is a tool to dress the surface of a grinding wheel. Grinding dressers are used to return a wheel to its original round shape, to expose fresh grains for renewed cutting action, or to make a different profile on the wheel's edge. Utilizing pre-determined dressing parameters will allow the wheel to be conditioned for optimum grinding performance while truing and restoring the form simultaneously.
A water jet cutter, also known as a water jet or waterjet, is an industrial tool capable of cutting a wide variety of materials using an extremely high-pressure jet of water, or a mixture of water and an abrasive substance. The term abrasive jet refers specifically to the use of a mixture of water and an abrasive to cut hard materials such as metal, stone or glass, while the terms pure waterjet and water-only cutting refer to waterjet cutting without the use of added abrasives, often used for softer materials such as wood or rubber.
Milling cutters are cutting tools typically used in milling machines or machining centres to perform milling operations. They remove material by their movement within the machine or directly from the cutter's shape.
A lathe center, often shortened to center, is a tool that has been ground to a point to accurately position a workpiece on an axis. They usually have an included angle of 60°, but in heavy machining situations an angle of 75° is used.
An end mill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit in its application, geometry, and manufacture. While a drill bit can only cut in the axial direction, most milling bits can cut in the radial direction. Not all mills can cut axially; those designed to cut axially are known as end mills.
In machining, boring is the process of enlarging a hole that has already been drilled by means of a single-point cutting tool, such as in boring a gun barrel or an engine cylinder. Boring is used to achieve greater accuracy of the diameter of a hole, and can be used to cut a tapered hole. Boring can be viewed as the internal-diameter counterpart to turning, which cuts external diameters.
Knife sharpening is the process of making a knife or similar tool sharp by grinding against a hard, rough surface, typically a stone, or a flexible surface with hard particles, such as sandpaper. Additionally, a leather razor strop, or strop, is often used to straighten and polish an edge.
A cold saw is a circular saw designed to cut metal which uses a toothed blade to transfer the heat generated by cutting to the chips created by the saw blade, allowing both the blade and material being cut to remain cool. This is in contrast to an abrasive saw, which abrades the metal and generates a great deal of heat absorbed by the material being cut and saw blade.
Ceramic tile cutters are used to cut ceramic tiles to a required size or shape. They come in a number of different forms, from basic manual devices to complex attachments for power tools.
In the oil and gas industry, a drill bit is a tool designed to produce a generally cylindrical hole (wellbore) in the Earth’s crust by the rotary drilling method for the discovery and extraction of hydrocarbons such as crude oil and natural gas. This type of tool is alternately referred to as a rock bit, or simply a bit. The hole diameter produced by drill bits is quite small, from about 3.5 inches (8.9 cm) to 30 inches (76 cm), compared to the depth of the hole, which can range from 1,000 feet (300 m) to more than 30,000 feet (9,100 m). Subsurface formations are broken apart mechanically by cutting elements of the bit by scraping, grinding or localized compressive fracturing. The cuttings produced by the bit are most typically removed from the wellbore and continuously returned to the surface by the method of direct circulation.
Surface grinding is done on flat surfaces to produce a smooth finish.
A disc cutter is a specialised, often hand-held, power tool used for cutting hard materials, ceramic tile, metal, concrete, and stone for example. This tool is very similar to an angle grinder, chop saw, or even a die grinder, with the main difference being the cutting disc itself. This tool is highly efficient at cutting very hard materials, especially when compared to hand tools.
An annular cutter is a form of core drill used to create holes in metal. An annular cutter, named after the annulus shape, cuts only a groove at the periphery of the hole and leaves a solid core or slug at the center.