A thermal model is presented for deep grinding with particular relevance to the HEDG process. HEDG is defined as deep grinding at high workspeeds and very high removal rates. The contact between the workpiece and wheel is represented as a circular surface. It is found that the contact angle and also the Peclet number (widely used in heat transfer and defined below) have strong effects on the grinding zone temperatures. Experiments were carried out to demonstrate the high removal rates achievable and to measure the resulting contact temperature. It was found that high removal rates and absence of thermal damage could be achieved as predicted. The new model is shown to provide a good estimation of contact temperatures. It is also confirmed that HEDG can achieve low specific grinding energy compared with shallow grinding and creep grinding. The chips take away a substantial proportion of the heat generated in the grinding process. As in creep grinding, burn-out of the coolant causes a steep rise in contact temperature of the workpiece.