Exactly,,,,,,,,,,,Grant it,I don't know nearly all the material speeds and feeds along with figuring them out for the different unique variables,but I can figure a lot with out no table or charts.Comes from doing it for thousands of times.There is no way any tool library can take into account all things.Coatings alone,render it useless almost.Heck,holding a part in a vise compared to clamped to the table can have a big effect.It's great for getting in the ball park,especially for materials not use to running.I certainly would not count on Bob's feeds or speeds as being the "Bible",nor do I hold them responsible.Run 1st part conservatively and work your overides to optimize.Edit program accordingly,if needed.This is where the "machinist" uses his eyes and ears and experience.
Bobcad guy,I never agreed with you more,a lot of people don't agree with me on this,you get it
Even using FS Wizard,which is far Superior to Bob's,IMO,,I don't always do what they suggest,sometimes not even close.Zero Divide is a big fan of chip thinning,where as I like to hog stuff out.As there is many variables to determine feeds and speeds,there are different styles and strategies of metal removal.And that alone will also change speeds and for sure feeds.
Under powered machines,lack of rigidity,Chinese cutters,coatings,geometry of cutter,doc,loc,tool holder,coolant,dry,this goes on and on.A problem I have been running into lately is different machinability from one supplier to another for the same material,,especially 303 and 1018.How do you ever calculate that?