Ok this does have a bearing on the design so please be patient with me, If you were machining these Z parts what would your Cutter preferences be and why, this will help me when i finalise the design, so please everybody pipe in, Remember What type and Why please, if you prefer then PM me as i know some of you wizards like to keep your advantage secret, but please let me know. Right off to bed now 4 hrs should do LOL speak after 1..