LATHE TOOL POST GRINDERGeneral The tool post grinder is a portable grinding machine that canbe mounted on the compound rest of a lathe in place of thetool post. It can be used to machine work that is too hard tocut by ordinary means or to machine work that requires a veryfine finish.
Trilobites are an extinct group of arthropods (jointed-legged animals) known from more than 10,000 fossil species. The group Trilobita existed from early in the Cambrian Period (520 million years ago) until the end of the Permian Period (250 million years ago).The name Trilobita is derived from the three (tri-) lobed structure of the exoskeleton, which has a raised central lobe (or axis) and a pair of side lobes, called pleurae.efore the first trilobite with its legs fossilised was described in 1870, it was already well established that Trilobita belonged to the Arthropoda. Arthropods are the most species-rich animal phylum living today, and have been the most diverse group of multicellular animals since the Early Cambrian.
Trilobites had many life styles; some moved over the sea-bed as predators, scavengers or filter feeders and some swam, feeding on plankton. Most life styles expected of modern marine arthropods are seen in trilobites, with the possible exception of parasitism (where there are still scientific debates).rilobite fossils are found worldwide, with many thousands of known species. Because they appeared quickly in geological time, and moulted like other arthropods, trilobites serve as excellent index fossils, enabling geologists to date the age of the rocks in which they are found.