Re: Silly question
hy i just looked for the mt3 shape, and is loooong, thus big l/d ratio
long parts can not be easy put in a chuck, as front end, or back end, my have tir, and back end is impossible to test in a normal chuck
but let's put asside the possible tir, as there are chuck setups designed for low tir chucking of loooong parts : even if there would be no tir, machining a collet in an opened/free state, requires real low cutting force : for example, going from 4 to 5 should not be done with a 5 drill, but 4.1 4.2, etc... and even so, the result is not a quarantee; drils may go sideways, they have their own mind, even on an 'alingned' lathe; turning instead of drililng, is more gentle, but final bore may no longer be coaxial with the collet
to adress both tir and low cutting force, it may be better to have a custom fixture on a vmc ( helix toolpath ) or wire machine; the custom fixture should quarantee for paralelism and center, while the helix/edm is gentle enough, at least much more than a turning operation wold be
let's supose that both fixture and machine are prepared : next issue is collet hardness
putitng all those head to head, it may be cheaper to just buy another, or craft a new collet / kindly
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