Many of the tools currently used in placing and finishing concrete were conceived and developed as hand tools long before energy sources other than manpower were available. The adaptation of power in some instances has greatly reduced the effort required of the operator, but is a trowel any less a hand tool because the main rotary motion is provided by a gas engine rather than by the operator? We think not, but nevertheless for convenience this deals exclusively with tools powered and directed by hand. Floats are used either to give the surface its final finish or to prepare it for steel troweling. The darby is a float made of wood, aluminum or magnesium. The larger size darby is normally used in the kneeling position. Tapering the width of the darby blade will make the operation of the tool easier. Darbying on a larger scale is done with a bull-floa , usually from 48 to 80 inches long. This too is fitted with a long handle and is invariably rectangual and wider than an ordinary darby. Trowels are used for all spreading, shaping, and smoothing operations during concreting. The rectangular shape has remained unchanged for generations. There are several factors to consider when buying a trowel. The steel should provide a correct balance between long-wearing hardness and flexibility. Suitable final grinding will ensure that the trowel is perfectly floated and bordering at the factory before being sold. The blade must be rigidly fixed to the handle. A forged mounting with stainless steel pins is better than rivets construction because rivets tend to rust and loosen. Groovers, also known as jointers, are used to cut grooves in the surface of fresh concrete. The tool is sometimes manufactured in combination with an edger. Multiple groove tools are sometime sided for edging steps so as to provide a safer surface. Most grooves are intended as contraction or control joints which predetermine and hide the location of cracks. Groovers may be made of stainless steel, bronze and malleable iron.