step over amount

[dustinwassner]

could i hear some general percentages of cutter dia. that one would use to step over when milling, along with the depth of cut. it seems to me that a larger step over with less depth would be better because the chip would then be the correct thickness? when doing a full dia cut is it common to drop the feed rate to 1/3?
thanks

[ViperTX]

Actually step-over has more to do with how flat do you want a surface to be. Based on my limited experience....it seems that most milling bits have some radius..so rather then creating a true flat cut you end up with a cut that is cupped. So, step-over reduces the height of the ridges of the cupped cut.

Paul

[dustinwassner]

but stepping over 10% of the dia vs 50% will give a different chip thickness correct? and if you are going to mill at say 10% cutter dia. depth vs 80% you would need different step over amounts for each?

[RICHARD ZASTROW]

If the step-over leaves "cupped" or "notched" surfaces, the machine's geometry is messed up. If this happens, tram the machine and correct the geometry.

If that doesn't work, I'd use a fly cutter to put on the final finish cut. But then I'm picky.

Dick Z

[dustinwassner]

so really you would want to take a 100% step over and shallower cut depth for roughing and finish with a larger depth of cut and small steps? And again, will the stepover amount of 20% vs 50% change chip thickness? when a manufacturer says that the tool should be set up for .002 chip load and you run your forumlas is the formula feed assuming that you are doing 50% dia step over?