Hi Allen and Jeff, Thanks for the tips about the cutter profile - worked a treat but I wouldn't want to do too much machining of copper. Sticky, isn't it? Also - feedback to those who gave me advice on machining my brass chimney base. I've got a very acceptable result and I now know which are my sharp files and which are not! Where would I be without access to this group? Many thanks Dennis MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.