Question: Chip breaker ?
- Thread starter scott99
- Start date
pmace
Elite Cafe Member
Chipbreakers on machine tool bits or inserts are black magic and everybody seems to have their secret geometry. In our case I don’t see where there is enough room on the face of the tool to do anything meaningful. The chip is too big in relation to the tool. Some geometry to drive it off to the side without it steering the cut off course would be interesting though.
mitch
~ Elite 1000 Member ~
- Joined
- Jul 23, 2007
- Messages
- 2,651
i'm not putting any 'skewed' angle on the face of the graver (it stays square to the axis of the tool), but as i'm sharpening the face on a 600grit diamond wheel i touch it to the wheel so that the 600 grit polish 'grain' doesn't go straight up the face of the graver, it runs at a slight angle. so when i'm cutting a line the 'chip' (like the cutting off a lathe, if that's what you're calling the "bur") tends to follow the polish grain on the face of the graver, and curls off to the side away from the soft gold inlay. it not only prevents the curling chip from digging into the gold, it also keeps it from obstructing my view of the gold edge i'm following. this trick also works for just cutting borderlines along a scribed line.
this would be easier to explain if i had the ability to shoot photos of things as small as a graver face, along with video of the chip's behavior as it curls up while cutting.
mitch
~ Elite 1000 Member ~
- Joined
- Jul 23, 2007
- Messages
- 2,651
does everybody know what i mean by the "polish grain"? i'm referring to the direction of the microscopic scratches left in the graver facets by the abrasive of the sharpening wheel or stone. in this case, i'm deliberately making these scratches run at an angle to the centerline of the face of the graver so that the chip being cut out of the surface of the metal being engraved is guided off to one side, instead of curling up straight ahead of the graver face/point (or toward the gold inlay, which is even worse).
this trick has to be done on a rotating wheel (like a GRS PowerHone). sweeping the graver across a stone won't work. (i suppose one could carefully slide the stone out from under the graver, while it's held in a sharpening fixture?) anyway, i just sharpen like usual, then make sure the graver face is at the desired angle relative to the rotating disc for the last couple seconds or so.
you probably need to use a fairly rough (600 grit) wheel, otherwise the "grain" will be too smooth to have any effect on the chip as it moves across the graver face. also, as mentioned previously, you don't want the polish grain to be at very much of an angle to the centerline, or the chip will just skid across the micro-furrows, not follow them.
this trick has to be done on a rotating wheel (like a GRS PowerHone). sweeping the graver across a stone won't work. (i suppose one could carefully slide the stone out from under the graver, while it's held in a sharpening fixture?) anyway, i just sharpen like usual, then make sure the graver face is at the desired angle relative to the rotating disc for the last couple seconds or so.
you probably need to use a fairly rough (600 grit) wheel, otherwise the "grain" will be too smooth to have any effect on the chip as it moves across the graver face. also, as mentioned previously, you don't want the polish grain to be at very much of an angle to the centerline, or the chip will just skid across the micro-furrows, not follow them.
Last edited:
dlilazteca
~ Elite 1000 Member ~
Got it, all clear now, going to have to try that and label them for border cutting, in theory a left and a right can be made.
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Sent from my SM-N950U using Tapatalk
Marrinan
~ Elite 1000 Member ~
Thanks Mitch, Fred
mitch: tyvm. now i understand exactly what you do to the face.
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