Does my knife have an imperfect heat treatment?

[Wook]

I've had my Arthur Wright and Son two bolster Senator knife for about two months now. I got it for fathers day and I have been very happy with it.

One thing struck me about it though. I can never seem to keep it sharp. I'm not the worlds best knife sharpener, so I put that down to me. But even when I was very careful about how I sharpened it, it never seemed to hold its edge. Then I thought I was closing it too aggressively and the edge was knocking on the inside and being blunted, so I took to closing it more gently. It still kept happening.

Tonight I conducted an experiment. I took it to my strop with autosol on it and sharpened it, and then took it to my plain strop till it was like a razor. It was popping hairs off the back of my hand. Previously I wondered if my knife hadn't be truly sharp, but only had a kind of surface sharpness. So tonight I made sure it was truly, actually, in reality... sharp!

Then I cut up a largish orange with it. I didn't close it in between or anything like that. Total time from the strop to finishing cutting up the orange was less than 10 minutes.

Afterwards it wouldn't even drag the hairs on my hand - it felt (almost) blunt.

Is it possible that my knife has an imperfect heat treatment and that the metal is too soft? Are there any other possible explanations?

I love this knife, it's gorgeous. But at this rate I'm going to have no knife left within a year. I'm having to sharpen it 3-4 times a week just from sharpening pencils at work and cutting up the odd bit of fruit.

I've heard nothing but good things about these knives, so if there is an issue I'm guessing it is the exception rather than the rule.

I sent an email to the manufacturer to see if they think it is defective, or if there is another explanation.

Is there anything else it could be?

Since this was a gift from my wife and kids I'm kind of gutted. I've always dreamed of owning a knife like this

PS- The knife did not carve those spoons - it was there for scale only. It doesn't seem to hold an edge long enough to use for that sort of thing.

 

[brancho]

I suggest now you have asked Athur wright about this you wait for a reply and should just waited rather than post this.

 

[robin wood]

Sheffield penknives tend to be tempered fairly soft, most you can cut with a file. Spyderco owners would definitely consider that imperfect heat treat, our grandads would have liked the fact they could quickly put an edge on with simple sharpening stones. I don't know how hard the knife you have is tempered or what you would like but however soft it is it would be possible to set up an edge that would hold, you just need to give it a steeper angle if it is blunting quickly. That may mean it doesn't shave so well but penknives are not made for shaving, razors are, they are very hard and have an edge at about 12 degrees. I recently spent 3 months working wood with bronze tools which were less than 45 rockwell, that is very very soft yet once we got used to setting the edge up we would work green oak with them 8 hours a day without sharpening.

 

[Hoodoo]

I have had knives that shaved hair and immediately blunted after carving a piece of wood. The culprit has almost always been a very fine thin wire edge that was not removed by stropping. Now I often use a power strop followed by buffing on an unsewn buffing wheel. Mainly I would suggest stropping longer and harder and perhaps raising the angle just a bit to bend that wire edge (but don't roll it) back and forth to eventually remove it. A tiny secondary bevel will often work. I have run knives very lightly over crocksticks at a slight angle greater than the bevel, then stropped and that usually works as well.

An uneven heat treat might cause problems but I don't usually have a problem with moderately low Rockwell knives. My Martindale Golok is easily worked with a file but once I get the final edge on it, I've chopped limbs that I've trimmed from my trees in the yard and dried for a couple weeks. I can chop for over an hour with not a nick to be seen or a shine on the edge of the blade and sitll plenty sharp.

If you sharpen your knife, then cut across the end grain of a piece of hardwood and scratches appear almost immediately, I'd bet it's a recalcitrant wire edge.

 

[bushwacker bob]

IIRC Wrights use 420SJ steel which is fine for edc type stuff like cutting string, opening boxes and chopping your lunchtime fruit but a bit lacking for hard use such as whittling or carving. You would encounter the same edge retention problems with most Sheffield standard production knives and even with the likes of Trevor Ablet.
As Robin said ' horses for courses' but there are compromise ways of getting the best out of it.

 

[Wook]

According to Heinnie Haynes, the Senator uses C70 Carbon Steel.

Hoodoo you may be right that this knife just requires a bit longer on the strop than some of my other knives. I tried giving it 70 or so strokes on the strop (a lot more than I would usually) and the edge didn't seem quite so mind-blowingly fragile afterwards. I was out of oranges, but this time at least it was not blunted by the act of cutting up an apple.

I'll use it for a few more days and see how it holds up.

 

[bushwacker bob]

Not imperfect HT then, just imperfect sharpening.

 

[Wook]

Well after a few days of carrying my much more extensively stropped knife, I've come to a conclusion.

Things are not as bad as I feared, but not quite as good as I hoped. By giving the knife much more stropping than I am accustomed to doing, it does indeed seem to hold its edge better. After 3 days of light use opening boxes and cutting fruit, it had gone from hair popping sharp to hair dragging sharp. I gave it a wee touch up tonight.

It still seems to be much softer steel than my old SAK which it replaced, which could go 2 weeks of this sort of use and remain hair popping sharp. It even seems softer than my other Sheffield carbon steel knife, a 20 year old scout knife. It holds an edge like you wouldn't believe, so I don't think it's a carbon vs. stainless thing. Perhaps Sheffield is not producing as high quality barstock as it did 20-30 years ago?

Arthur Wright & Sons still haven't responded to my enquiry so I never got to hear if they thought this was normal.

 

[Samon]

I know it might sound a bit excessive, but.. try stropping the knife 100+ times after a proper sharpen. Then just strop lightly after each use.

I don't mind a soft blade, but yours sounds a little too soft. I mean an orange shouldn't blunten your blade..

wait for the maker's reply and see what he says. it does looks like a nice knife but from what I've heard about that particular maker is his knives aren't excellent anyway. Particularly his choice in grind hight/angle for his 'bushcraft' knives.

I'd say a sak blade is about right for a mulipurpose every day knife. any softer and it'll get unusable too quick and any harder will mean more risk of chipping/snapping the blade.

 

[Hoodoo]

I would send it out to be sharpened by someone you trust to do an excellent job. Then if it dulls too quickly, you will know that the steel is too soft.

 

[Hoodoo]

I should add that sometimes a new knife can be brittle at the edge due to overheating of a thin edge during heat treat. Sharpening the blade back a bit can often result in a dramatic improvement.

 

[Wook]

Well, I raised my concerns with Heinnie Haynes after Arthur Wright and Sons never replied. Heinnie said to post the knife back and they'd have a look.

They just posted it back to me. They said they checked the rockwell hardness and found it to be fine,. They also reground the knife, putting the quite extreme grind it had when new back on it. They also polished my hard won patina off! They didn't charge me for either of these so I'll take it in the spirit in which is was offered.

Perhaps the knife just isn't suited to the kind of grind I had put on it. Over the course of several months of sharpening, I had put a steep, slightly convexed, almost scandi grind on it. This was partly on purpose, partly a side effect of the way I sharpen knifes (on a strop with polish) but mostly because I found the thing needed sharpened 3 times a week for 3 months. The grind Heinnie have put on it is a extreme single bevel set at almost 45 degrees to the vertical. That puts a lot more meat behind the edge than I am accustomed to for a pocket knife - almost axe like.

I did email them back and asked what the knife scored for Rockwell hardness. I have a feeling they will rate quite soft - although from what they are saying it sounds like they are meant to be like that.

Now the real question is should I allow this knife to displace the Victorinox Tinker I bought to stand in for it? It hasn't given me any trouble at all, and it only cost £13 to the Arthur Wright's £50.

There's no denying it's pretty, but after last time I have some serious reservations about its practicality.

 

[cbr6fs]

Try it with the steeper grind see how it goes.

It's really about finding a compromise.
Steep enough grind to last, but still shallow enough to cut well.

It's the same with hardness.
If it was really hard then it'd hold a edge but be a nightmare to sharpen.

So i would Persevere but gradually bring the angle of the grind down till it starts needing sharpening to often, then take the grind angle up slightly after that.

Such a nice looking knife it'd be a shame not to try and tailor it to your uses.

 

[FGYT]

all the Sheffield pen knives ive had including T ablett are a very soft blade compared to modern stuff like a SAK
this is how that are My TA is in a box somewhere i now carry my own made penknives in O1 or 52100 steel as i know they are ok and the Kydex folder is smaller thinner and lighter to

ATB


Duncan

 

[Wook]

Heinnie got back to me on the hardness:

The Rockwell hardness tested at 44-46 and that is normal for a A Wright knife.

Perhaps one of the knife makers could confirm for me, but isn't that very very soft for a knife, even a carbon steel one?

 

[bushwacker bob]

Yes it is. Even SAKs are 54-56, but it was traditionally acceptable as they are easy to sharpen.

 

[Wook]

Well mystery solved I guess. The blunting was a combination of an incredibly soft knife coupled with me trying to put a steeper grind on it than the steel could support.

My kids would be upset if I stopped using my father's day present though, so I'll see how I get on with the axe style grind Heinnie have put on it for me.

If I need to sharpen it every few days, so be it. It's still dear to me because of who gave it to me.

 

[Perrari]

Yes that is very soft for a knife. I have had a look on their website for the 2 Bolster Senator, and they specify 54-56 Hrc for that blade, which would be fine, but 44-46 is too soft in my opinion, and not in line with what they specify it should be.

http://www.penknives-and-scissors.co.uk/acatalog/Pen___Pocket_Knives.html
It's the last knife on this link.

 

[Wook]

Thanks Perrari for that link.

I emailed them back drawing their attention to it and asked them if they are sure 44-46 is normal....

They'll probably think I'm being a nuisance.

 

[Perrari]

Nuisance or not, it doesnt sound right to me. And as a customer you have been sold something that is not right. Good luck !