Hmm. It says that I do not have permission to view the page when clicking on those links.
Whoops, there may be a donation requirement for access to downloads.....sorry I did not mean to tease you.
I went looking for a link to the rules for the downloads section and did NOT find it......I will post back if I do.
I have used that Little Machine Shop calculator too.
left the cutting speed at 90 fpm (still not quite sure I understand fpm in this context)
Yeah, that can be strange to get your head around at first. I believe the terminology really comes from lathe work, where the RPM of the work piece and the work piece diameter together determine how fast the outer surface of the work is coming past the tool bit. (Actually it's the work piece circumference that matters, but that can be calculated from the diameter, or radius; C = 2 * pi * r = pi * d)
However, since the exact same math applies to a milling machine where you spin the tool (an end-mill), the same terminology is used.
The only caveat is accounting for the multiple cutting edges of the end-mill vs. the single edge of the lathe tool bit.
Another handy speed/feed calculator resource is the Niagra Cutter Speed/Feed slide rule that you can get for free:
http://niagaracutter.com/speed-feed-slide
Someone here had posted that link years ago....I was doubtful, but they did send one to me in Canada.
My thanks to whoever originally posted it.
For 90 fpm, and 1/4" end mill my slide rule shows about 1375 rpm.
Then for a 7 ipm feed rate that gives about 0.0013 chip load.
Does this all seem correct to you?
So yes my slide rule agrees with the LMS online calculator.
-brino