2-362-333 - Worldwide Photography/Heritage-Images

Tensioning circular saws at Slack Sellers & Co Ltd, Sheffield, South Yorkshire, 1963. In order for a circular saw to run true at speed, the saw blade should be slightly convex. The blade will revert to being flat when it spins at speed. In the photograph, the blades are checked to ensure that to correct curvature has been achieved in the tensioning process.