Having bought a hole saw and arbor from Screwfix and put them together in
what I think is the correct configuration I was frustrated by the fact
that the pilot drill was barely longer than the depth of the hole saw
which made it very difficult to align it with the mark for the centre of
the hole.

I located a screw on the side of the arbor and removed the drill to check
the size and look for a longer one.

Turns out that the drill had 3 little notches in the shaft to allow pre-
setting different drill lengths.

Who knew?

Still a bit of a fiddle to make sure the grub screw located properly in
one of the three notches, but at least a variable length pilot drill.


Cheers



Dave R


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AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64