Dull bits? Long bits? Your feed rate is definitely too fast for your
setup, find the weak link and you can increase the feed rate..
I have been trying to mill a 1/4" dado in hard maple 3/16" deep. A couple
of days ago I asked about "climbing" bits as my onsrud spiral cutter was
coming out of the router. Followed the advice ftom several folks on the
wreck and all went well....... exect that I broke the router bit.
I then switched to a a second 1/4" bit, this time a two flute carbide tipped
straight cutter -- broke it as well after about 4 linear feet of milling.
Both bits snapped right at the collet so the whole bit broke, rather than
just the tip.
now admittedly the second bit was not top of the line (it was from rockler)
but to have two bits break doing the same operation in such short amount of
time seems a bit weird. Both bits were 1/4" shank. I have been unable to
locate a 1/2" shank witha 1/4" straight cut -- 3/8" seem to be as narrow as
1/2" shank bit go.
I was doing this in a router table with a PC7518 router mounted in a PRL.
My feed rate was reasonable, _maybe_
Anybody else had this problem -- I'd like to do some thinking before I head
back to the shop and snap another bit !