The sides and bottom of the keyway should be surfaced true with the file. If a keyway is to be cut by hand through a bore, as in a pulley or gear-wheel bore, its width should be marked with a T-square. This head is also driven by a key which engages a keyway in the boring-bar. The rod end should be planed to thickness for the brasses and of equal thickness on each side of the keyway. The flat key is used where it is necessary to secure the wheel more firmly without weakening the shaft by cutting a keyway in it. A much more usual method, however, is to employ slotting or keyway drills.
 Igneous, metamorphic, and sedimentary are descriptive terms used to  classify types of rocks, not minerals su â¦ ch as diamond.     Diamond is accepted as a valid mineral by the International  Mineralogy Association.
Igneous rocks form when rocks are heated to the melting point which forms magma. Sedimentary rocks are formed from the cementing together of sediments, or from the compaction (squeezing together) of sediments, or from the recrystallization of new mineral grains which are larger than the original crystals.chists are usually named by the main minerals that they are formed from. Bitotite mica schist, hornblende schist, garnet mica schist, and talc schist are some examples of this. Gneiss is a high grade metamorphic rock. This means that gneiss has been subjected to more heat and pressure than schist.