Craftsman helps shells fly true

BAE Systems has been a long-standing customer of Craftsman, having for many years being supplied with a variety of mandrels, but it is the first time it has chosen the West Yorkshire business to supply collet chucks. One of the main requirements was that BAE Systems needed to be able to machine inside the shell casings with great accuracy so as not to affect the trajectory of the finished product. Collet chucks provided the best solution, as they would not distort or mark the outside of the shell casings when being held, as they clamp parts on to the lathe during the internal boring and facing operations. Craftsman’s designers insisted on high quality steel, hardened and ground to precision limits with accuracies of 0.005 mm TIR, in many instances. The components themselves were of nominal 105 mm and 4.5” sizes, requiring quick change-over of collets. All collet slots are fully sealed to prevent ingress of swarf and coolant oil into the mechanism. Loading is simple, direct and repeatable, with a positive release incorporated by utilising the machines’ double-acting drawbar system. Manufacture of the collet chucks took place in Craftsman’s Delaware Cell – the business is divided into five such “blocks” with Delaware being responsible for all the company’s workholding products. Andrew Cassie, manufacturing engineer, from BAE Systems, in Birtley, near Chester-Le-Street, County Durham, said: “Up until now Craftsman Tools has supplied BAE Systems with a variety of mandrels and we have been impressed with the quality of their products. “Choosing a supplier that offers a full design service through to manufacture was an important factor in bringing Craftsman Tools on board for the collet chucks.” Craftsman Tools managing director Robert Johnson, said: “Having an existing customer turn to us for a product we have never previously supplied to them is not only testament to high the quality of work we produce, but also to the one-to-one relationships we have established over the years." Pictured: Craftsman Tools' North Cell, one of several focussed production cells.