I recently bought a bunch of masonry drill bits at a boot sale. Most either fit in a chuck or are SDS. However, a few have triangular shanks which I've not come across before. The bits are not huge, I guess between 12 - 20mm. The triangular part is about 1/2" across the flats and about 1" long.
I've tried various search terms with no luck. Does anyone know what type they are and what drill takes them?
John