[CAUT] hammer boring jigs?

[ricb at pianostemmer.no]

Probably thee best type of jig ever... mounts on a lathe... nothing
is faster or more precise. Tho I've not seen this particular one I
have seen a near cousin here in town... and I'd love to talk the
fellows (who dont use it btw) out of it..

http://pianomaker.co.uk/technical/boringmachine/