Dubbing a graver.

[Gordon]

Would someone be kind enough to show a close-up tip of a dubbed graver. I've read a bunch of descriptions of HOW it's done, (and I'm sure that I'm being really dense), but I'm just not getting what is meant in a way that I can visualize what that looks like.

 

[graniteguy52]

Check out the discussion on Steve Lindsay's forum:
https://www.engravingforum.com/showthread.php?t=4018&highlight=dubbed
It includes a drawing of a dubbed graver.

 

[jerrywh]

I personally think dubbing is a dumb idea. A dubbed graver won't cut they plow.

 

[Sinterklaas]

If you round the point a bit, just like a round graver. It should still cut and not plow, wouldn't it?

So only remove some metal from the bottom facets. Not the front.

 

[SamW]

For hard metal I double dub...I put a very small facet on the tip of the face at perhaps 80 or so degrees (compared to the heel) followed by rounding the heel very slightly. Cuts fine for me and lasts much longer cutting hard metals like stainless slides, etc. These are made on a fine grit ruby stone and almost need magnification to see.

 

[jerrywh]

If you have a 80° face and a 20° heal the tip will be perpendicular to the surface. How can a geometry like that cut???

 

[SamW]

The dubbed face angle is in relation to the heel so with my usual 8 or 10 degree heel (lift) the tool has a 70 or so face in relation to the length of the tool or in other words about a 10 degree cutting angle. Close to vertical but off enough to cut OK.

 

[jerrywh]

Sam. Now I understand. but--- Why not cut the whole face angle at a steeper angle?

 

[monk]

it may very well be dumb, but sorta smart when needed.

 

[SamW]

Jerry, I'm too lazy to change the dual angle settings and as I usually sharpen 10 or 12 gravers at a time and use some of them for other purposes I just do them all the same. The dubbing only takes a couple of seconds using a two very light strokes on the stone.

 

[mitch]

Sam. Now I understand. but--- Why not cut the whole face angle at a steeper angle?

The 'point' of dubbing this way is to make just the very tip of the graver stronger, where it is weakest and where virtually 100% of all gravers eventually fail. The remainder of the face, which is more gently sloped, and the edges up the sides of the face, still do much of the cutting and lifting metal up out of the groove, but the tiniest bit of the tip, which is buried at the bottom of the cut and enduring the highest forces, is no longer quite so fragile.

 

[SamW]

Mitch has it spot on! I looked at one of my dubbed tools with the idea to take a photo but the area is so small I gave up on the idea.

 

[jerrywh]

Never tried that method but now that I understand it better I see why. I just use a 55° face angle with a 20° heal and a small flat on the bottom of the heal all on a Cmax graver or a glensteel.

 

[FANCYGUN]

Jere
I do mine a bit different...i think....
When i am done sharpening myngraver, i just hold it upon my ceramic stone vertically and just scratch the tip on the ceramic this gives it a itty bitty blunt tip When cutting, the regular face angle does the removal but the blunted tip does not touch metal thus preserving the tip this is the way Frank Hendricks showed us how to do this using a ruby stone Now this i do not use when doing my banknote as I want a super sharp tip Im not going deep and the metal is resonably soft also

 

[monk]

so little is risked when experimenting ( not on an actual job), that the effort may pay off.

 

[SamW]

Marty, that is much the same as I dub only I don't hold the graver quite vertical. The "itty bitty" tip I make is about .002" wide as measured with an optical measuring devise.

 

[sam]

Here's my dubbed 120° point done with a quick swipe on a ceramic stone.

 

[mitch]

you made a nano-scorper, Sam! if i'm following him correctly, "The Other Sam" does much the same thing, but on the face.

 

[SamW]

Yes, that is what my "dub" looks like. It is on the face, just steeping the face at the point to near vertical in relation to the cut.

Sam's photo looks like the dub is on the tip of the face but steeper than (or passed) vertical. And I see no lift added.

 

[sam]

It's just a light swipe across ceramic holding the graver approximately vertical. I don't think about it much...I just do it. There may be better ways than this.

Churchill will radius the bottom keel line of the heel for strength. I've done that as well, but tend to just dub the tip unless more drastic measures are called for. And quite frankly, if dubbing doesn't work I don't care to be engraving whatever it is because it's no fun cutting something that dang hard