The Ghost Ship(ment)

 My face (shell) milling cutter has finally arrived...

 

 I may be expecting too much, but so far I am not impressed.

  I haven't done a good cutting test yet because after I installed six inserts, I was shocked at the variations in cutting insert tip height when I measured the thing on the plate, at which point I stopped to figure out what was going on.

 Well, it turns out there are two things going on: 

 Thing One: the inserts themselves vary in dimension by a surprising amount - from .738" to .746":

 At first I assumed this was just shit manufacturing, but when I decoded the entire insert call-out code (APMT1604PDER) I discovered that this is a very low-tolerance insert (that's the 'M'), suitable only for roughing.  These inserts measure within their specification, they're just cheap-ass, low-grade inserts. Well, I can buy others.

 Thing Two: the insert mounting pockets in the shell itself vary in height by several thousandths at least; I haven't completed a formal survey and written down the numbers.  That is NOT normal, and it's not in anybody's specs!  For a shell mill to provide a good surface finish (and they are capable of very good surface finishes, when the inserts are right) the inserts must all be at the same height.

 I've asked the seller for clarification, details, specifications, manufacturer, explanations, etc, but I don't expect to get anything useful because China.

 So, another painful - but not terribly expensive - learning experience.

  And amusingly, it may be possible to even up the cutting tip heights by measuring all the pocket heights and installing the appropriate over- or under-sized insert in each so that the height differences cancel out as much as possible.  Okay, perhaps not so amusing to actually do in practice.

 Gumble.