This the the attachment for my Harold Hall grinding rest, made exactly to the instructions in the Workshop Practice Series book on tool and cutter sharpening. The attachment is suitable for grinding both the end and side teeth of an end mill or slot drill. With the appropriate indexing collars fitted, it can sharpen two, three, four and six flute cutters. The attachment works well in conjunction with the grinding rest.
I made a set of four collets to suit metric screw-shank end mills. It would also be worth making a set for imperial sizes. A drawback of this sort of design is that a separate, bespoke collet is needed for each size of end mill. It would be good if the design could be modified to use ER collets as this would enable all sizes within the range of the collets to be used.
Drawings and Construction Notes
This is not my own design, so drawings are not available from me!