Proxxon 6 piece hss boring tool set proxxon 24520 p this six piece set of cutting tools for use with the proxxon pd 230 e and pd 400 lathe systems is supplied in a wooden box p p each set comprises one of each cutter for 60 deg metric threads and 55 deg whitworth threads for cutting internal threads 1 3mm 2 65mm and 4mm boring bars and a tool holder these cutters are held in a tool holder that mounts to the tool post of either the pd 230 e or pd 400 p proxxon 24520 6 piece hs