Re: I'm sure this has been asked before

In article <g1dsb9$mi6$1$8300dec7@xxxxxxxxxxxxxxxx>, Boo <reply_to_group_not_me@xxxxxxxxxxxxxxxxxxx> writes
The reason for not using end mills (4-flute cutters) for cutting slots was well explained by (IIRC) GHT in one of his books (may possibly have been Tubal Cain). Briefly, the leading tooth of a 4-flute cutter puts a sideways stress on the cutter, which means it deflects sideways a bit, thus it is not exactly where you wanted it.

Can I provide an addendum to this argument ? Obviously the leading tooth on any cutter puts a sideways force on it and this is also true for a 2 tooth cutter. The question is why does the effect not occur for 2 tooth cutters when it does for 4 tooth ones ? The reason is because the 4 tooth cutter has a tooth engaged at the side to which the force is acting and so it can cut itself in sideways whereas the 2 tooth cutter has its back tooth in open space at the time when the fron tooth is applying the maximum sideways force.

Yes, omitted to mention the reason, but that is exactly it.

David
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David Littlewood
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