Extendable slot and spring board for establishing linear measurement for tradesmen e.g. carpenter, plasterer

摘要

The slot and spring board has an exchangeable inner rail to determine different lengths. At the upper and lower part of the slot and spring board, a slot is milled to fix at a gypsum or plaster burning angle. The length and angle can also be exactly adjusted by the alteration of the slope in the stairwell. Tension springs are located in the rail, so that slippage is not possible.