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When drilling stainless steel on a drillpress and clamping my workpiece on a machine vise the drill likes to grab the material right at the time when the exit hole reaches its final diameter. If I'm lucky, the bit will only slightly grab the material, without further problems. If I'm unlucky, the bit yanks the machine vise out of my hand, and smashes it against the table drills column or simply breaks, half of it stuck in the hole.

I usually use low cutting speeds (180-300rpm) and ample cutting fluids. A technique I use to reduce the problem is to drill the last 0.5mm at much higher speed (1000rpm) and very light downward pressure which works fine on flat, horizontal materials. If I'm drilling into round stock or something more complex, with internal holes I am forced to use my hand drill with torque control set to no more than 5nm. But this is hardly very professional.

Woodworkers put another sheet of wood below their workpiece to make exit holes nicer. With metal parts that's rather impossible, as the part needs to be clamped tightly in a vise. Is there a professional way of doing it without wrecking my tools?

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  • There's no metalworking community on stackexchange, so this and "home improvement" where the only options I have. I decided to ask here, as every wood worker owns a drillpress and standard HSS drills.
    – AzulShiva
    Dec 27, 2022 at 13:39
  • Sorry, VTC because off-topic is off-topic. Beyond @EliIser's P.S. you're probably better off asking any such questions on one of light-engineering or general metalworking fora out there (of which there are many) for a guaranteed audience of experienced posters. For this query there's no need to, if you search the archives of any of the relevant forums you're sure to find numerous repeats of the standard advice on safely drilling stainless.
    – Graphus
    Dec 27, 2022 at 17:37
  • @Graphus ok, if it's off-topic, then move it to "home improvement", don't close it.
    – AzulShiva
    Dec 27, 2022 at 23:05
  • It's off-topic for there too! Like I said, you can find your answers elsewhere, with better assurance they'll be accurate/reliable and much much faster.... if you'd done as I suggested you'd have been done literally five minutes after you read my Comment.
    – Graphus
    Dec 28, 2022 at 10:59

1 Answer 1

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the bit yanks the machine vise out of my hand

That's your problem right there - clamp or bolt the vise to the table of the drill press.

Even when drilling into wood the drill bit can catch the piece on exit and try to spin it, so ideally you'd want to clamp anything you drill. Most folks don't do that for wood and for the most part it works out fine. For metal (especially thicker stock as your post suggests) I'd argue you should always clamp your work.

PS I'd suggest future metal working questions go to Home Improvement stack exchange, simply for the much larger audience.

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  • Out of the question. 1) If the drill is unable to spin the vise, then the drill will simply break, leaving me with a much bigger problem 2) I cannot bolt a vise down for every hole I have if I can't move the vise. I would need a cross table table which moves along the X and Y axis and bolt the vise to that table. I could exchange the mandrel on my mill for a drill chuck and drill the holes there, but as of now my mill is not for drilling.
    – AzulShiva
    Dec 27, 2022 at 23:11
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    "If the drill is unable to spin the vise, then the drill will simply break" - that shouldn't happen if the bit is drilling true. My observation with wood is that the bit will grab if there is any movement in the piece relative to the press. If the piece is clamped the bit never grabs.
    – Eli Iser
    Dec 28, 2022 at 2:12
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    "I cannot bolt a vise down for every hole I have" - so either live with the safety risk and drill bit breakage with hand held vise or invest in an cross-slide vise/table. That's the problem with safety features - if they are not convenient to use, they don't get used...
    – Eli Iser
    Dec 28, 2022 at 2:15

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