Mounting Work on Mandrels To machine a workpiece of an odd shape, such as a wheelpulley, a tapered mandrel is used to hold and turn the work.The mandrel must be mounted between centers and a driveplate and lathe dog must be used. The centers must be alignedand the mandrel must be free of burrs.
Rotifers: the wheel animalcules. Rotifers are microscopic aquatic animals of the phylum Rotifera. Rotifers can be found in many freshwater environments and in moist soil, where they inhabit the thin films of water that are formed around soil particles.ther animals with a pseudocoel, such as rotifers and acanthocephalans, appear to be more closely related to Lophotrochozoa, a large alliance of protostomes that includes molluscs, annelids, brachiopods, etc. Phylum Rotifera is divided into three classes: Monogononta, Bdelloidea, and Seisonidea.
Phylum is comprised of two classes, Eurotatoria (which includes orders Monogononta and Bdelloidea) and Seisonidea, with over 2,200 currently known species. They are most commonly found in freshwater, although some species live in brackish or marine habitats, in soil, or on mosses. Rotifers may be sessile or sedentary and some species are colonial.