Endmill smear of metal

[Nigel McBurney 1Participant @nigelmcburney1]

why spend cash on new end mills and carbide bits,when a simple home made flycutter with a hss toolbit or broken centre drill ground up to shape costs next to nothing and will produce a better finish as the tool tip rad,cutting clearances,rake etc can be chosen to suit the job by using a bench grinder.The burr is manly caused by blunt tooling.

[Jon LawesParticipant @jonlawes51698]

As my mill is smaller I have found flycutting a nerve-wracking experience (vibratory!) and avoid it where possible. I use a carbide insert shell mill instead with good results. It was £25 including R8 fitting and it gets used quite a lot, so I don't begrudge the money.

Jason, good experiment, thank you. It does look like took sharpness is the critical factor?

[AdrianRParticipant @adrianr18614]

I find I tend to feed too slowly or vary during the cut, what I did was download a metronome app. I set it to tick at twice the speed I need to rotate the feed. Then just follow the ticks top, bottom, top … when turning the feed.

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