Posted by Chris Mate on 16/01/2022 13:02:04:
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The question is with milling machines the spindle and whole operation is more secure, and with drilling machines(The home types) less so. So the question is is the slight play or forgiveness in drill presses more to the favour of the drill bits, less stress on them, than a mill will put on it drilling seeing it does not cut sideways as in milling, so if it wonders off a fraction the mill will put force on it to stay straight-?
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I feel the drill press and mill work in slightly different ways, and use a different technique.
No significant play in the mill so I align the firmly clamped work by DRO, (no marking out or centre-punch), make a straight starter hole with a centre-drill, switch to the twist drill and go for it. If necessary I countersink and ream to finish-off. It's all done by swapping cutters, because X,Y and Z are all controlled.
My pillar drill has noticeable side play, one of the reasons it can't mill. Also results are poor if it's set-up and used like a mill. However, the spindle runs accurately on its axis when spinning, and it drills accurately if the job is allowed to float into the right position. So, the job is marked out and centre-punched, lightly clamped to stop it dangerously escaping but just able to move sideways, and moved to align closely with the spinning twist-drill tip. If on contact the drill shows any sign of moving off-axis, the job is allowed to slide so the drill stays on axis. Once aligned, holes are straight and in the right place. If the drill is forced into a slightly off position centre-pop, or clamped rigid as on the mill, the hole curves because the drill bends, and moves the spindle.
I use the same twist-drills on all my machines, avoiding too cheap, and the jobber type intended for woodwork.
Dave