Grinds

[Ed Fowler]

I just sharpened a bunch of little medical scissors called "Iris scissors " by a local physician. These are used by physicians for delicate work cutting both suture material and human tissue. They were all dull, I put a very mild convex grind on them for him and he claims they cut better than when they were new, or when they used to send them out to be "professionally sharpened". Took me abut 15 minutes per set. Incidentally they all have a 320 grit edge finish.

We have to remember, all convex grinds are not equal, not should they be. The grind has to match the purpose, the convex grind is very adaptable for most purposes.

 

[Fiddleback]

The convex grind is also more time consuming than flat or hollow since you have to use light pressure against the belt. With flat and hollow grinds you can "lean into it" and hog off steel at the start then lighten up near the end. Also dull belts will still cut when you add more pressure (flat & hollow), whereas I found only new sharp belts will remove steel convex grinding.
Bruce

Excellent post!

 

[Diomedes Industries]

And if you just want a sharpened prybar with a horrible apple seed edge geometry, then it is pretty easy, and it'll cut things when you're done.

I agree with this statement Andy. I have had PLENTY of convex grinds in my hand and the difference between a good one and a crappy one can be subtle - but obvious when using.

I received a knife the other day that cut decently - but after three or four hours on the stones and strop it was GREAT. Subtle - but obvious.



I agree also with what Ed is saying. Not all grinds are created equally. I LOVE this simplicity and beauty of a good Scandi - this is why I had Andy make the Arete as a Scandi. However, I have learned that while this grind excels at cutting medium to soft wood - it does not do as well as other grinds at almost all other things.

This is why I am having Andy make me a Convex Arete - I will use this knife during the times when I plan to be cutting harder wood, or slicing, or dressing meat.

Ed is right - not all grinds are the same (nor should they be) and not all grinds of the same type are the same (nor should they be).

This is a great thread.

TF