Circle cutters?

[Duncan A]

If using a punch, do it on endgrain; it cuts far better.
Duncan

 

[joethedrummer]

,,went down the sharpened holesaw route and just bashed the discs out with a club hammer on the end of a bit of elm,, got hold of a couple of tame site plumbers and relieved them of their blunt holesaws,,

 

[Sachakins]

Wow "...tame plumbers..." I've never come across that rare breed before