The photo is of a cutter that has been running on trial for a long time at a large foundry. Carbide blades have been set into Dartek and angled off like an impellar, scraping away the sand to the centre of the cutter and away.It does over 3000 holes before the blades need changing. The cutter was quick and easy to make. As Dave always says " Draw me something on a bit of paper, and I will make it.For all details email patdarby@btinternet.com or phone 01287 610183