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Thread: Sharpening a Centre Punch
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26th Jul 2021, 05:41 PM #16
Hi Guys,
One of the reasons that I like my pyramidal shaped one is that the point is very sharp which make it easy to find a scribed line or intersection. Its also easy to touch up the flat sides. The conical point on the normal ones tend to round off particularly if you are heavy with the hammer blows.Best Regards:
Baron J.
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30th Jul 2021, 09:35 AM #17Mechanical Butcher
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Is it tricky to grind a pyramidal point, in terms of getting all flat surfaces to intersect perfectly at the point?
For a conical point, I chuck a centre punch in a pistol drill.
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30th Jul 2021, 09:49 PM #18
Hi Jordan,
No I would say not ! I've never had any problem, but I do use a 45 degree angle plate on the DE bench grinder table as a guide.
The harder part might be deciding whether you want three or four sides to the point. My punch was originally purchased with three sides, so all I do to touch it up is set the flat to match the side of the wheel, though I have occasionally stoned the flats to get the tip sharp again after being a bit heavy handed with the hammer. The trick is to treat it like a prick punch and re-punch with a normal cone tipped punch if you want a larger marking.
The only other thing I would mention is hardness ! Because the tip is so small its easy to destroy the hardness when grinding, so you have to be careful not to overheat it.Best Regards:
Baron J.
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15th Sep 2021, 05:36 AM #19Intermediate Member
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- Jul 2021
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drill sharpening with hand drill
if a drill fits in a hand drill, and you can really FUBAR'd it, skewing the sides up or messed up the angle you can use this trick
ideally you wanna run it counter clockwise while sharpening it on band grinder so it doesnt bite into the belt itself
you can adjust the angle of the tip with this and both sides will be equal lenght. then you just gotta touch both sides to get the cutting part of the drill done
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15th Sep 2021, 05:54 AM #20Intermediate Member
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indeed making it 3-4 sided helps, reference arrows used for hunting.
one place i worked we had to make some sharpened rods for penetrating something- i truly cant remember what the hell it was, but the conically sharpened spears didnt do much, but the ones that were 3 point or was it 4 point went right through, because as it expanded the material, the points would make a weakpoint and actually cut the material, causing it to breach and break rather than expand while adapting and pushing against- if that makes any sense
i believe it was some kind of fabric we had to punch through, but on the nano scale im sure steel can work the same way but surely wont "cut" as easily
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