Grinding a Convex Grind

C

Carson Falk

Joined
Apr 28, 2017
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I have run into a problem on a customers knife. He is wanting a convex grind but I have never done one before. Does anyone have any suggestion on how to grind one? He also wants it with a zero degree bevel, has anyone had any experience doing this particular grind? Any suggestions would be greatly appreciated!!!
 
Use the slack potion of your belt grinder, i.e not the platen. Is that what you're asking? Are you trying for a full height convex grind or just a convex edge?
 
palmerdl said:
Use the slack potion of your belt grinder, i.e not the platen. Is that what you're asking? Are you trying for a full height convex grind or just a convex edge?
Click to expand...
I'm just looking for a convex grind not a full height grind. Is there any way I can do this with a platen and the slack of the belt? I don't have much slack on the belt of my grinder.
 
Can you remove your platen? By the slack portion, I mean the belt section between the platen and the wheel. The part of the belt NOT supported by anything. I know that's not the right term, but my mind is blank right now.
If you use the platen, you will pretty much get a flat bevel grind.
 
When you said the customer wanted a zero degree bevel, that led me to think you were talking a full height convex grind from spine the edge... no bevel or secondary edge.
 
Not to sound like a smart ass, but if you've never done one do you really want to roll the dice??
I know if it was my knife, and I'm paying you to perform sharpen it, I'd like to have that nugget of info BEFORE you start creating sparks!!
Just a suggestion.
 
Find out if your client simply wants a convex secondary bevel or a zero full height. The zero full height will be one plane from spine to cutting edge, gradually sloping according to requested angle. This could impact the thickness of the knife depending on how shallow you need to go.

A convex edge would be a secondary bevel that is slightly rounded and has no shoulders because they are blended into the primary. The thickness of both the spine and primary bevels are not affected with this type of edge.

My suggestion is to summarize this for your customer and find out which type of convex is desired before you grind.
 
I don't think it is only a matter of knowing HOW to do it... but also a matter of knowing WHAT DOES THE CUSTOMER REALLY WANT. It is as easy as drawing some knife profiles and tell him to pinpoint what does he exactly want. It is not that hard.

Sometimes we just get lost into the verbal description of something that could be easily fixed drawing a few lines on paper.

Also, once you get to know what he wants, I suggest you practice on mild steel flat bar. It is a cheap insurance to make sure your technique provides you with the results you are after.

Best of luck.
 
I find the sweet spot is right below the idler pulley.

When I started, convex V grind was all I did.
 
Until you know you can do it, you shouldn't be charging for doing it... Decline the order until you know how and have practiced.
 
Carson Falk said:
I have run into a problem on a customers knife. He is wanting a convex grind but I have never done one before. Does anyone have any suggestion on how to grind one? He also wants it with a zero degree bevel, has anyone had any experience doing this particular grind? Any suggestions would be greatly appreciated!!!
Click to expand...

Carson Falk said:
I'm just looking for a convex grind not a full height grind. Is there any way I can do this with a platen and the slack of the belt? I don't have much slack on the belt of my grinder.
Click to expand...

What kind of grinder do you have? Usually, there's enough space in front of, or behind a platen... or maybe near a wheel. It doesn't take much "free space" to create a convex edge (in fact, you don't want to use a really slack portion... the grind can become too steep).

Also, what kind of knife?
 
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