# CNC Machining Coin Dies



## SilverWorker (Aug 7, 2013)

Hello all! New member to the forum and I just want to say first thanks for the wealth of knowledge given in the spirit of friendly generosity that the members here have contributed! I look forward to contributing and hope that I can share something interesting. I first posted this in the General forum and got a suggestion that I might check over here.

I make jewelry and recently got a small desktop size TAIG cnc mill for cutting wax models for casting. I've been very happy with the results and can't recommend the machine highly enough to anyone in a similar position. They are also made in the USA by a small family owned business so that is a plus in my book. I've recently become interested in coining and am exploring the possibility of cutting steel coining dies with my machine to use for making jewelry in gold and silver in a press or drop hammer.

I don't know much at all about machining metals, so I was wondering if anyone has any experience in a project like this? While searching YouTube for information I found a video that provides some speeds and feeds for a similar machine & project.
Link to the video: https://www.youtube.com/watch?v=rP9vnt4xUvQ
Using  20 000 RPM spindle and a carbide single flute 30 degree side angle pyramidal engraving cutter with a .008 inch tip & feeding 4 IPM, cutting .012 inch deep on the finishing pass. The gentleman in the video mentions that at that setting each revolution of the cutter is taking off about half a thousandth of an inch of metal.

My machine is equipped with a 10 000 rpm spindle, so I'm naively wondering is it feasible to just buy a cutter with double the tip diameter and keep the other settings the same, or is there something I'm missing? I'm sort of ignorant of what needs to be taken into account to size the tooling and settings for a given job, is there a basic theory behind it? Any good resources that are worth recommending to help get me up to speed would be most appreciated! I am pretty much a complete newbie when it comes to machining metal, I've only done wax on very small desktop sized machines.

Thanks in advance for any help!


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