Material and tool selection

[MeJasonT]

I have been trawling back through some old youtube videos of John Saunders NYCCNC
He's such a charismatic bloke you sit there watching for hours, unfortunately not much sinks in to my old grey matter.
Its a little contradictory to what this topic aims to achieve but it certainly removes some of the precision and accuracy to get the exact feed and speed. I was under the impression that SFM's were the science behind the material structure and how it disintegrated under the tool. Its hard to get your head around the fact the tool is cutting despite the fact you know you are not using the tool manufacturers specification. Despite the contradictory information the newbie still needs to get the feed and RPM somewhere in the ball park. Its also daunting when you have a suggested RPM in the region of 15,000 RPM and your machine is only capable of 5,000 RPM. I have the advantage of knowing my milling machine cut materials long before high speed CNC centres were invented or high speed milling techniques. Thankfully John has debunked the manufacturers stringent specification.

Another stumbling block is knowing how much to cut with WOC and DOC (Width of Cut and Depth of Cut) and the different coronations used to to name woc and doc by different tool manufactures and coursebooks etc.

[ncollar]

Jason
I've always liked John S's material. The only thing some of us will never have the equipment like he plays with. I do like a lot of his ideas that can be used in a home shop. The biggest thing I picked up is the radius on end mills. It kind of makes sense when you think about it. We break the cutting edge on HSS cutting tools on the lathe and why not on the mill? It is the sharp point that produces the cross hatch marking. I have several new .625 end mills, I'm going to touch it up with a fine grade slip stone to break the point. Just as soon as I get in the shop.
Thanks for the info.
Nelson