On Sat, 11 Apr 2015 11:09:21 -0500
Leon lcb11211@swbelldotnet wrote:

Any way I burned through several carbide straight bits with each
session. Then, one day a machinist neighbor brought me a 3/8" 4
flute HSS end mill bit. I never replaced a that bit and it cut
probably 1200 slots with no indication of dulling. These things are
designed to mill steel, Milling wood is childs play for these type
bits.

this is very useful info

Having said that there are regular plunge slot cutting bits that have
a point on the end. These type bits will do a much better job of
plunge cutting if all your slots will be through slots.

also useful


If you plunge deep holes you want as large of a bit as possible to
prevent deflection. You also want up cut as a deep hole will clog
and cause burning and smoking if you use a regular straight bit and
or down cut.

so far everything you've said means that they should use a 4 flute
end mill bit (not the pointed plunge slot bit)

http://vimeo.com/105610468

i think they use a 1/2-inch shank 1/4-inch router bit but would benefit
by using the 4 flute end mill bit

benefits are
cheaper initial price
plus ability perform a lot more work over its lifetime

all good things and maybe other benefits like
better swath cleanout as it goes and
improved accuracy at 60inch/minute cut rate