An aggressive yet flexible wood carving knife

[O'ReillyMade]

Folks,

I've got a head scratching request. My grandfather builds and competes model airplanes and with this he carves his own propellers out of balsa wood. For the past 30 years he's used a pretty typical wood carving knife with a blade length of around 4" that features a scandi grind. However, he has recently requested that I build him a similar knife that has some flex to it.

I've mulled this one over for a bit now and I've come to the conclusion that these two qualities in a knife are conflicting. It seems that flexible and aggressive are a difficult combination to achieve. My only thought is to use a thin stock (likely 5160) around 3/32 or under and "scandi grind" it resulting in a shallow primary bevel. The knife would have an unconventional appearance but the edge geometry should hold up still, and the stock thin enough that it has a bit of flex.. I think.

So... what do you think? Is this the right approach and if so, what thickness of stock should I be shooting for?

 

[Stacy E. Apelt - Bladesmith]

I would start with .06" stock and grind it thinner if he wants flex. W2, 1095, 26C3, all would work well. I would pick 26C3 for his set of parameters.

I have to be honest and say I can't think of any reason he would want a flexible carving knife for the job you describe. I think what he really wants is a curved knife. How about making him a set of knives with one curved left, one curved right, and one straight.

 

[O'ReillyMade]

Stacy - that is all great food for thought. Thanks for the reply

 

[Richard338]

I would start with .06" stock and grind it thinner if he wants flex. W2, 1095, 26C3, all would work well. I would pick 26C3 for his set of parameters.

I have to be honest and say I can't think of any reason he would want a flexible carving knife for the job you describe. I think what he really wants is a curved knife. How about making him a set of knives with one curved left, one curved right, and one straight.

In that case use AEB-L and grind before HT. The random warping will have them curving in all directions!

Edit to add something useful: This link shows many impressive examples of carving and whittling, and includes discussion of tools. https://www.bladeforums.com/threads/whatcha-whittlin-these-days.838442/

 

[Mecha]

Titanium blade has the flex as a material, but really, imo the way to control flex is through distal thickness taper regardless of material used. It makes a blade act like the arm of a longbow, flex-wise.

 

[Danke42]

Most proper wood carving knives have tiny little blades so pretty hard to flex.

Maybe ask him to show you examples of other knives like he's thinking of. It may be a case of lost in translation.

 

[Mitchell Knives]

I made a few out of .06" 15N20 and they turned out great. I think I heat treated them to 60 HRC if I remember correctly.

 

[weo]

Are you overthinking this? IIRC, balsa wood is pretty soft, so is he just looking for a more flexible blade than what he's using? I'm not sure how thick his carving knives are, but it seems like all you'd need to do is make him something thinner.

 

[Bigfattyt]

Also possibly look at 15n20 for thin blade steel.

Strong and flexible.

I have a "puko" I made out of it at .07 stock.

Pretty easy to heat treat to get high hardness, and still be strong.

Honestly, with .07 stock, pre heat treat/pre Decarb sanding, I could make that knife thinner, and ir would still be robust enough to carve. The edge is a convex/scandi.