Endmill failure or wrong feeds and speeds?

[Lee Roberts]

Evening Oli,

Well chip load also known as the Feed Per Tooth is actually supposed to mean the length of material being loaded into each cutting edge, so there can be a difference because you could argue for all the dimensions of a chip: width, length, thickness etc., so chip load is really referring to the length of the chip...

It is to be known as the theoretical length however, as other things like the width of the cut and/or flute edge geometry affect the thickness of a chip. If you measure the thickness of said chip accurately, the thickness you read wont give you the same numbers as the original chip load that was calculated.

Personally I think calling it chip size generalises it and makes it a simpler thing, in the beginning I did the same as you and didnt really give it enough thought so also didnt really know what "chip load" meant, I jumped straight to a basic speeds and feeds chart with no pictures etc, I quickly worked it out from there and since I've always called it chip size to myself and when explaining to people...

We both learnt something from this today, I did underline all of the instances where I called it chip size in my other post, on the assumption that you and others would notice that and get it, however I realise now I should have just made it clearer, sorry about that.

Have you tried cutting MDF yet?, reason I ask is because not many people realise (me included) that if you get the formula right for cutting MDF, it too will produce proper chips, I was really surprised by that and always thought of MDF as a dust only kind of thing to be working with, its quite a good material to learn and "chase" the correct chip on...