Quote Originally Posted by birchy View Post
That's a countersink not a counterbore? Big difference between the two. I also had a quick search for counterbores with a combined pilot drill so that you could effectively drill and counterbore without changing tools but came up blank. I've worked in engineering for many years but have never seen such a tool. Or at least not a proper one. I guess you'd have to get a lump of tool steel and make your own or make one by grinding a suitably sized drill bit.
i must have dreamed them up then i was sure i had seen them before.ive got to use some counter sink allen bolts plan is to put in a pilot holes then manually counter sink the material on the bench drill,i can get by but would have prefered them to have that pilot guide on the bottom like those flat bottomed counter bores do