Soft blade tang or fully hardened, on full tang O1 knives

[Londinium Armoury]

I've finished drawing up the designs of a knife pattern I'm going to be sticking with, moving away from thick blade stock and moving onto much thinner handles. I'm going to be using O1 at quite a high hardness, around 62 - 63 HRC, the stock will be 3mm thick, FFG with micarta Handles, maybe acid stone wash finish.
I'm just left with 1 thing I haven't decided on, how to leave the tangs, I'm not sure if it would be better to leave the tangs completely soft, or fully harden and temper the tangs along with the blade.
What do you guys do with your 01 blades, these will be general purpose knives, 4.5 inch handles, some with 5 inch blades, some with 4 inch blades. not very wide, around 1 inch.
Would you harden the whole piece or leave the tang soft. I will put a picture of the knife design at the bottom of this post, so you can see exactly what they will look like, it is drawn to exact size.
As they will be quite thin, would you think a soft tang will hold up to some peoples abusive usage? I was thinking if a lot of force is placed on them they might bend and take a set around the top of the handle where the scales end. Then if they are fully hardened and the tang has a spring temper, then if they are abusively bent, the scales might start to pop off due to the spring tension of the knife.
So what is preferable, scales starting to come off due to spring tang bending, and maybe epoxy coming loose above the pins. Or blade possibly taking a set where the handle starts.
I know people shouldn't be bending my knives like this, but I'm sure some people will at some point.
What do you guys do with full tang knives that are through hardened, or have you changed due to any benefits of the alternative method.
Thanks.

O1 blade pattern https://imgur.com/a/zNdAY56

 

[A.McPherson]

Here's your pic

Just harden the whole thing. There's nothing to gain by making the tang soft.

Just drill your holes first!

 

[Londinium Armoury]

Here's your pic

Just harden the whole thing. There's nothing to gain by making the tang soft.

Just still your holes first!

Thanks for assisting with the picture and your input, haha I will 100% be drilling the holes first.

 

[HSC ///]

I wouldn’t call 3mm for that type of knife quite thin.

Scales won’t pop off with 3 riveted peened pins

 

[Londinium Armoury]

I wouldn’t call 3mm for that type of knife quite thin.

Scales won’t pop off with 3 riveted peened pins

Thanks for your input, I've never had scales completely pop off before, but when I made some fully tempered 2mm thick full tang blades, I did some bend tests on them and the pins held but right above the pins the epoxy bond failed, and you could notice a gap forming between the blade and scale.
It was still solid and everywhere below the pins remained fixed, but that little portion of the tang above the top pin, there was a gap where the epoxy bond had been broken. Maybe I put the top pin too far down, and if it was up higher this wouldn't have happened, but I was using wood scales and didn't want to put a hole too close to the top edge of the scale in case it cracked or formed a weak spot.
I'll be using micarta for this batch of blades so I can probably put the pin hole closer to the edge.

 

[Alex Topfer]

hardening the tang will make it take more force to deform, but will make it fail at a lower force. personally i think a bent tang is a better failure mode than a snapped tang. when steel snaps all that tension/energy has to go somewhere.

you have a 25x3mm tang, and most of the forces will be applied in the plane of the 25mm dimension. that's a lot of force to apply with a 250mm lever, and i would expect the blade to snap first.

if it were me, i wouldn't harden the tang. if someone manages to damage it i would ask what they were doing, and make something that is actually designed for that use

 

[Londinium Armoury]

hardening the tang will make it take more force to deform, but will make it fail at a lower force. personally i think a bent tang is a better failure mode than a snapped tang. when steel snaps all that tension/energy has to go somewhere.

you have a 25x3mm tang, and most of the forces will be applied in the plane of the 25mm dimension. that's a lot of force to apply with a 250mm lever, and i would expect the blade to snap first.

if it were me, i wouldn't harden the tang. if someone manages to damage it i would ask what they were doing, and make something that is actually designed for that use

Thanks for your input as well, I still haven't made up my mind, the new O1 stock arrived today, I usually make knives that are a lot wider than these, 2.5cm / 1 inch is the lowest width I've ever designed a knife.
I have until the end of this week to make my mind up on soft or hard tangs.
That's when my new shipment of Mapp Gass will be arriving.
I've even been toying with the idea of only hardening half of the tang, not sure what effect that would have, i'm estimating it might disperse some of the shock into the actual handle and allow a greater relief before extreme failure point. This is all guess work though, i've never tested it before. If I were running the blades at say 59 HRC (or around that number) I wouldn't have doubts about a hard tang, but as I'm aiming for around 63 HRC I'm thinking this might not be very good with bending and impact toughness. As they will be FFG and quite long slim blades at 63 HRC, I don't want them snapping, but i'm not too thrilled at the thought of them bending at the ricasso either because of a soft tang.
I guess I could make one of each style, then test them both and see which failure was worse, I don't honestly want to waste good steel though I'm not rich.

 

[Natlek]

Guys are you serious with this ...hard/soft thing on full tang knife ??

 

[Stacy E. Apelt - Bladesmith]

I can't see why you would want an O-1 camp knife at Rc63. Rc 61 would be much wiser. The tang isn't a risk issue either way. Harden it.

Before you start on the knife, put some shape into it. Right now it has the look of a knife shaped bar of steel. Drop the handle a tad and put a slight curved drop on the blade spine instead of the angular point. Look at some of these images fro how to do that:

 

[Natlek]

If that blade breaks it will be here !!

 

[Londinium Armoury]

I can't see why you would want an O-1 camp knife at Rc63. Rc 61 would be much wiser. The tang isn't a risk issue either way. Harden it.

Before you start on the knife, put some shape into it. Right now it has the look of a knife shaped bar of steel. Drop the handle a tad and put a slight curved drop on the blade spine instead of the angular point. Look at some of these images fro how to do that:

I could drop the HRC a point or 2, these were just intended to be general use knives.
I'm kind of stuck with straight handles for at least the first few knives. As they are going to be stock removal and take a look at how narrow the bar stock is here.
O1 stock and wooden blank template https://imgur.com/a/4iCC9Sy
So you think it was be better if I just order a new batch of steel about twice as wide so I can play with handle curvature? I think this narrow stock leaves nothing to play with in terms of setting a real curve.

 

[Londinium Armoury]

Guys are you serious with this ...hard/soft thing on full tang knife ??

Different makers prefer different methods, I know smiths who use soft and smiths who use hard on full tang knives.
I'm not sure what would be best that's why I'm asking for advice.

 

[Natlek]

Different makers prefer different methods, I know smiths who use soft and smiths who use hard on full tang knives.
I'm not sure what would be best that's why I'm asking for advice.

The weakest point is where the steel is thinnest.............

 

[Londinium Armoury]

The weakest point is where the steel is thinnest.............

So it would break at the plunge grind if the tang was soft or hard regardless?

 

[Hubert S.]

I could drop the HRC a point or 2, these were just intended to be general use knives.
I'm kind of stuck with straight handles for at least the first few knives. As they are going to be stock removal and take a look at how narrow the bar stock is here.
O1 stock and wooden blank template https://imgur.com/a/4iCC9Sy
So you think it was be better if I just order a new batch of steel about twice as wide so I can play with handle curvature? I think this narrow stock leaves nothing to play with in terms of setting a real curve.

You could make some Japanese kiridashi from the 1" bar. I would order something wider and maybe a bit thinner for a 5" blade.

 

[Horsewright]

Yep new steel and harden em fully. I've never had any break under the scales, a few tips but that wasn't the knife. Lots of knives ya can do with one 1" tall steel. Just not those designs. All less than one inch tall designs:

Very few of my designs I couldn't cut out of 1" tall stock.

 

[Britt_Askew]

maybe epoxy coming loose above the pins.

Make sure the blade is clean- no scale left on where the handles go. If the blade is clean and you are using good epoxy the epoxy shouldnt "come loose".
I did some test when I started making knives and if the scale was left on the blade and the handles glued on it didnt take much of a blow to knock the handle loose but if the blade was good and clean I could beat the crap out of it and the scales would hold tight.

 

[Londinium Armoury]

I can't see why you would want an O-1 camp knife at Rc63. Rc 61 would be much wiser. The tang isn't a risk issue either way. Harden it.

Before you start on the knife, put some shape into it. Right now it has the look of a knife shaped bar of steel. Drop the handle a tad and put a slight curved drop on the blade spine instead of the angular point. Look at some of these images fro how to do that:

O1 blank https://imgur.com/a/ISXDVNs
So I tried to see if I could add and taper or curve the tang when cutting the blank but it's just too narrow. I did round off the drop point though like you said, I could probably add some more length and rounded curve as I go.
On my next steel order I will grab some wider stock so I can play around.with the handle curve.
Thanks.

 

[Londinium Armoury]

Make sure the blade is clean- no scale left on where the handles go. If the blade is clean and you are using good epoxy the epoxy shouldnt "come loose".
I did some test when I started making knives and if the scale was left on the blade and the handles glued on it didnt take much of a blow to knock the handle loose but if the blade was good and clean I could beat the crap out of it and the scales would hold tight.

Hey do you know if acid etching will effect the bond similar to scale? I plan to acid etch and stonewash these whole blades.

 

[Britt_Askew]

Never used it , maybe somebody else will know.
You could acid etch a piece then epoxy some wood to it and whack it with a hammer to see how it holds.