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Machine Knives
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CONTOUR SAWING : calcium carbide Tools With carbideContour sawing is the process of cutting shapes in which the direction of the cut must be changed at intervals. Holes larger in diameter than the width of the saw blade must be drilled at each corner where a change of direction of the bandsaw blade will occur. illustrates the methods of changing direction of a cut at a hole Cutting tools |
Carbide Cutting Tools , Mchinery Carbide Tools |
The lathe cutting tool or tool bit must be made of the correct material and ground to the correct angles to machine a workpiece efficiently. The most common tool bit is the general all-purpose bit made of high-speed steel. These tool bits are generally inexpensive, easy to grind on a bench or pedestal grinder, take lots of abuse and wear, and are strong enough for all-around repair and fabrication. High-speed steel tool bits can handle the high heat that is generated during cutting and are not changed after cooling. These tool bits are used for turning, facing, boring and other lathe operations. tool bits made from special material s such ascarbides, ceramics, diamonds, cast alloys are able to machine
High Speed Steels
The main use of high speed steels continues to be in the manufacture of various cutting tools: drills, taps, milling cutters, tool bits, gear cutters, saw blades, etc., although usage for punches and dies is increasing.
High carbon steel remains a good choice for low speed applications where a very keen (sharp) edge is required, such as files, chisels and hand plane blades.
Types of high speed steel
High speed steels belong to the Fe-C-X multicomponent alloy system where X represents chromium, tungsten, molybdenum, vanadium, and/or cobalt. Generally, the X component is present in excess of 7%, along with more than 0.60% carbon. (However, their alloying element percentages do not alone bestow the hardness-retaining properties; they also require appropriate high-temperature heat treatment in order to become true HSS; see History below.) The grade type T-1 with 18% tungsten has not changed its composition since 1910 and was the main type used up to 1940, when substitution by molybdenum took place. Nowadays, only 5-10% of the HSS in Europe and only 2% in the United States is of this type. The addition of about 10% of tungsten and molybdenum in total maximises efficiently the hardness and toughness of High speed steels and maintains these properties at the high temperatures generated when cutting metals.| Grade | C | Cr | Mo | W | V | Co |
|---|---|---|---|---|---|---|
| T1 | 0.75 | - | - | 18.0 | 1.1 | - |
| M2 | 0.95 | 4.2 | 5.0 | 6.0 | 2.0 | - |
| M7 | 1.00 | 3.8 | 8.7 | 1.6 | 2.0 | - |
| M42 | 1.10 | 3.8 | 9.5 | 1.5 | 1.2 | 8.0 |
Coatings
to a cylindrical flat-bottomed hole, which enlarges another hole, or the tool used to create that feature. It is usually used when a bolt or cap head screw is required to sit flush with or below the level of a workpiece's surface (By comparison, a countersink makes a conical hole and is used to seat a flathead screw). The uppermost counterbores shown in the image are the same tool. The smaller top item is an insert, the middle shows another three-fluted counterbore insert, assembled in the holder. The shank of this holder is a morse taper although there are other machine tapers that are used in the industry. The lower image is of a plain counter bore designed to fit into drill chuck, and being smaller, is not economical to make as one piece.