Posted by mgnbuk on 01/06/2021 11:11:12:
Split drill driver
Had a bit more of a dig around & found the above link. These also seem to be referred to as "automotive drill" holders in some accounts & appear to require a drive square to be put on the end of the bit, with the parallel bore just to hold them concentric.
The "Use 'em up" repair sockets I initially thought of are not split.
Nigel B.
I have a small few long series drill bits, where the blunt end has a stepped pair of flats, much like the tang on a morse bit.
The shanks, seem higher quality finish than conventional drill bits, and may well be harder.
One is stamped HS, above a C in a diamond, above GB, which I assume is the trade mark; the other two are not marked at all, even for size.
I'm guessing they would be ideal partners to these collets.


The colour representation is about correct. The centre bit seems like HSS, but the outer two are noticeably heavier and only weakly magnetic.
Bill
Edited By peak4 on 01/06/2021 12:21:16