Convex edged broadheads?

[mellonhead]

Is anyone here sharpening a convex edge on their broadheads?  I have a couple knives with convex edges.  Once sharp they hold an edge and are easy to touch up.

Toby

[Terry Green]

Holding an edge has to do more with the metal and angle of sharpening....not convex straight or concave.

Some heads come with a convex edge......I personally don't put an convex on any heads of mine that didn't come that way.

[kbaknife]

The geometry of a cutting edge is determined by the function of the instrument.
A convex edge is designed for abuse in repeated cutting, and simplified sharpening. A knife, like the one you dress your deer with, is going to be in use during the field dressing, skinning and quartering of the deer for maybe an hour's worth of cutting.
It needs to have the edge to stand up to the abuse.
Then, you're not going to throw it away, so it needs to be easily re-sharpened.
The broad head you shot the deer with, on the other hand, only gets used ONCE on the same deer.
It needs to slice very cleanly and travel into the target as far as possible severing arteries along the way.
You're not going to shoot that deer 20 times with the same broad head..
The edge only needs to last 1/2 second.
You may sharpen it, you may not.
They're relatively inexpensive in relation to your knife.
When they get dull or beat up most of us just replace them.
Sort of like your disposable razor.
Sharp, flat grind for broad heads.
Convex for knives.

[Roger Norris]

Originally posted by kbaknife:
The geometry of a cutting edge is determined by the function of the instrument.
A convex edge is designed for abuse in repeated cutting, and simplified sharpening. A knife, like the one you dress your deer with, is going to be in use during the field dressing, skinning and quartering of the deer for maybe an hour's worth of cutting.
It needs to have the edge to stand up to the abuse.
Then, you're not going to throw it away, so it needs to be easily re-sharpened.
The broad head you shot the deer with, on the other hand, only gets used ONCE on the same deer.
It needs to slice very cleanly and travel into the target as far as possible severing arteries along the way.
You're not going to shoot that deer 20 times with the same broad head..
The edge only needs to last 1/2 second.
You may sharpen it, you may not.
They're relatively inexpensive in relation to your knife.
When they get dull or beat up most of us just replace them.
Sort of like your disposable razor.
Sharp, flat grind for broad heads.
Convex for knives.

Thats an awesome explanation. Thanks.

[kbaknife]

Another quick lesson in metallurgy:

"Geometry cuts. Heat treatment determines how long."

[Terry Green]

Yea Carl...that's what I said  ,,you just said it better  

[Glunt]

I shot a bunch of critters with Journeyman heads (convex) and a bunch with straight blade heads.  I compiled all the evidence and came to a conclusion...I can't tell any difference :^)

[Jason R. Wesbrock]

"When they get dull or beat up most of us just replace them."

When mine get dull I resharpen them. I can't imagine throwing away an Ace, Zwickey, or Eclipse just because it got dull.

[mellonhead]

Thanks guys.  I'll stick to a beveled edge.

Toby

[Sharpster]

Originally posted by kbaknife:
The geometry of a cutting edge is determined by the function of the instrument.
A convex edge is designed for abuse in repeated cutting, and simplified sharpening. A knife, like the one you dress your deer with, is going to be in use during the field dressing, skinning and quartering of the deer for maybe an hour's worth of cutting.
It needs to have the edge to stand up to the abuse.
Then, you're not going to throw it away, so it needs to be easily re-sharpened.
The broad head you shot the deer with, on the other hand, only gets used ONCE on the same deer.
It needs to slice very cleanly and travel into the target as far as possible severing arteries along the way.
You're not going to shoot that deer 20 times with the same broad head..
The edge only needs to last 1/2 second.
You may sharpen it, you may not.
They're relatively inexpensive in relation to your knife.
When they get dull or beat up most of us just replace them.
Sort of like your disposable razor.
Sharp, flat grind for broad heads.
Convex for knives.

Just for fun Karl...  For those who have the skill to do it, applying a convex bevel geometry adds a good deal of cutting edge durability.    

Ron

BTW, did you sell the knife with the grip made from the wood taken from front step of Abe Lincoln's childhood home???    

[kbaknife]

OK, guys. Maybe I could have worded things differently.
Point is, big difference in cutting tasks between knives and broad heads.
Steels used and heat treatments, geometries, etc are radically different.
We want a life time of use from our knives and hope to hand them down to the next generation.
If we get a season or two out of our broad heads we brag about it.
There's a reason to have a convex edge on a properly made knife.
And there's a reason to have flat ground edges on broad heads.
They do two different jobs.

[Jason R. Wesbrock]

So we're talking about the type of bevel, not the blade profile itself? In that case, this makes a lot more sense.  

[sledge]

i think i'm lost with jason.

convex head profile?  no thanks.  had a perfect broadside hit with a deadhead deflect straight up off a coyote shoulder.

convex edge profile?  as in curved?  never heard of it.

i can see the theoretical strength advantages, with arch-like edge support, but how do you do it?

or am i off-track?

joe