Harold Hall's grinding rest is only one of many similar setups. There is nothing wrong with it, it is no better, no worse and no complicated issues with basic tool grinding. I have built a Worden- somewhat worse, I am using an old Kennet which was the - and maybe still is, the easier to use than the Quorn.
All that is needed is to follow is ANY of the similar alternatives instructions. 4 facet tool grinding requires nothing more involved than the ability to make a drill holder which will do two faces- say at 5 degrees and then a flip over to do( say ) 15 degrees. The normal relief angles for a lot of applications. If you can grind do a lathe tool with one facet at( say) 5 degrees- you can certainly do end mills, slot drills and D bits by turning the lot over at 180 degrees- or two right angles.
There is- if my memory holds out, two articles one is by Gadgetbuilder and another- on the Kennet.
Whatever, all that a tool holder is a bit of square bar, with a scrap drill chuck. That Chuck is the de lux version!
All that you have to watch is not going past the centre of the work.
Good Luck, it is Dead Easy
Norman
