Convex and edge geometry.

[Shane Wink]

I am working on another bushcraft/survival style knife with a 3/16ths x 1 1/2 x 5" long blade and want to convex it but I am not sure how to know whether to go 1/2" 3/4" or full height. Should I flat grind HT then place the convex on the blade?

The intended use for this blade is to help me on my trapline this year. I cut and split a lot of wood for snares during trapping season and the knife I was using needs replacing.Cutting trigger notches and batonning through wood , trimming limbs, cutting rope as well as helping process some of the game will be its main function.

The one I am replacing was a blade I made a couple years ago.Flat ground with a convex edge. Many times I would have issue with the flats getting stuck in some hardwoods and I was worried about breaking the tip off but it never did. Now that my grinding skills are growing and knowledge as well I intend to replace it

Can anyone help me understand how high and how to grind the correct convex cross section for a blade like this with the above dimensions?

 

[Shane Wink]

I did find this helpful and it may help others that want to learn a good starting point for edge geometry.

http://coustil.free.fr/coutel_emouture_gb.html#pratique

 

[HHH Knives]

I want to thank you for the link. I saved it for future reading and study.

When I make a convexed field knife I tend to flat grind to a little less the 3/4 height on the blade. Then HT and temper the blade. Then convex and round a;; the way to the spine. Then I blend the flats to the edge, and also blend to the spine. For a final touch I have also been rounding the spine or at least relieving the hard corners.

It looks like you already found your answer, yet wanted to tell ya your on the right track. Have fun and show us your results and what you learned and how it works in the field.

God Bless

 

[Shane Wink]

Thanks Randy. I am piecing it all together a bit at a time but I am planning to take the edge down till it fails or rounds over then grunt back steeper till it does not fail. I am planning like you have mentioned to go up the blade 1/2 to 3/4 before ht with an edge thickness of approximately. 050. After ht setup the edge on the grinder and use the stone to make certain its straight and flat then back to the grinder to Blend the flats working through 220 to 600 on the black belts. Finish edge up with the 60 &30 micron belts.

I will be staying with 1084 from Aldo and keeping record of the ht and tempering in relation to the geometry of the blade till I find the right grind for my needs.