On Wed, 23 May 2018 10:05:39 -0700 (PDT)
Tricky Dicky wrote:

Are the threads on core drills standardised and a universal fit on
all arbors or are they manufacturer specific. I have an Erbaur arbor
but cannot get the specific diam. drill but can get one from another
source just wondered if I need to invest in another arbor and pilot
drill?

Richard

I've got a Macrist ddm1 and the 1/2 BSP arbor that came with it has
fitted every core I've tried.