Plunging Into A Pilot Hole

[richardsalzman]

I am starting my first project with 1018 steel making talon jaws.  I tested feeds & speeds on the same material running a simple straight line tool path.  I used these speeds/feeds to run the part.  The top slot & threaded holes worked perfectly.  I am stumbling on the simple pockets for the screws.  For larger pocket, the top one, I used the same 15 imp and .020 WOC that I used when I tested the F&S.  Since the pilot hole that the endmill drops into is .375", I calculated the reduced feed rate as (.375-.25)/.375 x the feed rate of 15 imp = 5 ipm

For the smaller hole, since the tool holder blocks much of the ability of the fog buster to get mist lubrication into the hole, I planned on using a slower base feed rate of 10.5 imp with a resulting reduced feed rate of 3.5 imp.

I just started running this project and when the endmill dropped into the pilot hole with a feed rate of 5 imp, it began squealing and vibrating.  Am I calculating the reduced feed rate improperly?

Richard

[richardsalzman]

Please disregard this post.  The endmill had pulled out of the tool holder.  I adjusted the F&S a bit and all is well!