I have a question, has any one come up with a jig or a devise to grind convex edges, with a Tormek?
I would use the slack belt part of the belt on a belt grinder for convex edges.
That stated, the "hollow grinding" issue with a large Tormek wheel is overblown. The hollow ground, concave edge mindset goes back to when most grinders had six inch diameter wheels.
Ken
Another issue I see is that illustrations are often not to scale so that the edge geometry can be easily seen in the viewer's mind.
When you use anything to grind with you are going to produce a negative image of the device you are using. So if you are using a round wheel, the negative would be a concave image. You have to do what Ken said but in reality the slight concavity of the edge you are producing is unlikely to ever cause a problem. I get your drift though.
I sharpened one of my "sharpening chisels" with my T7/8 and another with my T4. Comparing the two visually (naked eye), any attempt to determine which was which would be at best a guess. Looking very carefully using a rule as a straightedge, I could see a faint hollow grind (I think.) I realize that in theory, these edges are both concave; however, if I cannot see it, I don't worry about it.
Ken
You are right Ken. That is sort of what I say when I am putting up one of our yard greetings. Regarding straight lines as in a line of letters spelling out Happy Birthday. I make it straight to my naked eye and say to myself that if I can't see it, no one else can so it is straight!
Great comment, Jeff!
Ken
One would need an ovalized stone to do convex edges on a Tormek.
The mock-up in the pics shows how this would work.
(https://i.postimg.cc/sMrK04j5/Convex-sharpening-stone-2.jpg) (https://postimg.cc/sMrK04j5)(https://i.postimg.cc/jD4vVn2m/Convex-sharpening-stone-1.jpg) (https://postimg.cc/jD4vVn2m)
(Pics stolen from forum member Jan)
Carl,
I have seen two cases where convex edges are desirable.
- Some wood carvers, especially chip carvers, like their knives to have a convex edge. They say it helps to keep it from getting stuck in the wood.
- Some axe men (people?) like the sharpened edge to be convex (probably the same reason).
To do this on a Tormek would require an approach like achieved using a platform, and rotating the handle as you go. That is no different that sharpening on a flat stone though.
So it is possible, but for most tools I question the value. Having a repeatable edge has far more value.
Kind regards,
Rich
Hi Rich
I have 5 Bark River Knives, two of witch I have ground regular 15 degree edge. Bark River calls for convex edges on there knives. I know that there are hand sharpening systems that can grind convex edges. I was just wondering if Tormek guys had a devise or a process.