Trouble holding an edge - chisels

[YorkshireMartin]

Hello all.

Having purchased a few Narex (8101) chisels a month or two ago, I've now started to use them regularly. They have been used only in scandinavian redwood, for both chopping and paring. They have been sharpened without a micro bevel and are razor sharp. They cut very well indeed when freshly sharpened, like a knife through butter. They are sharpened from 250 through 1200 grit on diamond plates, then polished at 15k grit.

As far as I know, I haven't misused them. The trouble is, the edge is getting damaged in use, frequently. Not just dulling, but chips are appearing in the cutting edge, necessitating a fair amount of grinding to remove. This is unexpected, especially as I'm using softwood. The work they are doing has been a fair amount of cross grain for shoulders, but I still wouldn't expect to see 0.25mm chips in the leading edge after paring a single tenon, which is whats been happening in the worst case. No knots were present.

I'm using a wooden mallet and I would say I'm going relatively easy on them, not just bashing away like theres no tomorrow. I don't mind sharpening, I just didn't expect it would be so frequent.

I heard good reports on these, so I'm surprised. Having nothing to compare them to I'm a bit stuck. Is it worth buying a high end chisel to test against, or is there something else I could do to test my technique? I'm a beginner, so I suspect my technique first.

Many thanks.

 

[rkboston]

Try a tiny secondary bevel of 30 degrees or so and see if it helps. Also in new chisels very end can be brittle and chip, something to do with hardening. Do not rush to buy new chisels. Also when tapping them do not inadvertently move the handle right before the tap.. I am not an expert though.

 

[undergroundhunter]

Although I never experienced it with my Narex chisels, they are known for the edge chipping, this is caused by the hardening process they use and nothing to worry about. Do you have access to a grinder? the fix is to remove the first couple of mill of steel either by grinding of my normal sharpening (the latter obviously takes more time). Do you know what angle you are sharpening at? As hinted at above this can impact the edge retention, the standard it a 25 degree grind and a 30 degree micro bevel or if you free hand sharpen then you could use a convex bevel, but that's another discussion.

I'd go with option 1 first.

Matt

 

[Jacob]

The sharpening process you describe is a bit OTT if you are actually going to use these chisel rather than just being a sharpening enthusiast.
Using a chisel (or a plane) means sharpening a little and often, with no processing through grits, or polishing, other than a quick strop on your palm.
I'd also hold back on the grinder and get into sharpening without grinding at all, just reserving the grinder for remedial metal work.
And if they chip at 30º edge try a steeper angle.

PS You don't have to remove chips every time they happen, they are still usable with a little chip or two - just sharpen at a steeper angle and eventually they disappear.
The last thing you need is new chisels - what you do need is to find out how to make use of the ones you've got. Chisels are very low tech - they all are usable.

 

[bugbear]

Hello all.

Having purchased a few Narex (8101) chisels a month or two ago, I've now started to use them regularly. They have been used only in scandinavian redwood, for both chopping and paring. They have been sharpened without a micro bevel and are razor sharp. They cut very well indeed when freshly sharpened, like a knife through butter. They are sharpened from 250 through 1200 grit on diamond plates, then polished at 15k grit.

As far as I know, I haven't misused them. The trouble is, the edge is getting damaged in use, frequently. Not just dulling, but chips are appearing in the cutting edge, necessitating a fair amount of grinding to remove. This is unexpected, especially as I'm using softwood. The work they are doing has been a fair amount of cross grain for shoulders, but I still wouldn't expect to see 0.25mm chips in the leading edge after paring a single tenon, which is whats been happening in the worst case. No knots were present.

I'm using a wooden mallet and I would say I'm going relatively easy on them, not just bashing away like theres no tomorrow. I don't mind sharpening, I just didn't expect it would be so frequent.

I heard good reports on these, so I'm surprised. Having nothing to compare them to I'm a bit stuck. Is it worth buying a high end chisel to test against, or is there something else I could do to test my technique? I'm a beginner, so I suspect my technique first.

Many thanks.

If you're using a single bevel at 25 degrees, you (obviously...) have a final edge bevel of 25 degrees, which is great for paring, but a little fragile for general work.

I would recommend a steeper final bevel - 30 is classic, but anything "more than 25" is worth trying.

BugBear

 

[YorkshireMartin]

Thanks guys. They are sharpened with a 25 degree bevel. That might explain it.

I did hand sharpen another chisel as a test and it came out fine, much to my surprise, but even that one chips.

I'll put a 30 degree final bevel on one of them and see how I get along. Comment noted about it being new steel, too.

 

[Jacob]

A so-called "micro" bevel isn't going to make the edge much stronger until it has got a bit "macro". The more you hone at 30º the stronger the edge.

 

[matthewwh]

Nothing much to add, all the advice given above is excellent and I'm sure that increasing the honing angle will resolve the problem.

It is worth bearing in mind that softwoods can be very unforgiving on cutting edges, especially if there is a great variation in hardness between soft fluffy summer growth and hard resinous winter growth and knots.

 

[D_W]

Thanks guys. They are sharpened with a 25 degree bevel. That might explain it.

I did hand sharpen another chisel as a test and it came out fine, much to my surprise, but even that one chips.

I'll put a 30 degree final bevel on one of them and see how I get along. Comment noted about it being new steel, too.

You may need to go even a skosh above 30 degrees on a newer chisel that may be on the soft side. It's unfortunate if you have to, but some of it may be you and the chisel "learning each other" (of course that's you learning to use the chisel in a way that it responds well to you).

Some chisels are tolerant of our abuse even when it doesn't seem like abuse (e.g., if the handle moves a little bit as you're striking it), and some aren't. In order for a chisel to be completely unusable, it has to be getting toward saw temper. Anything in mid to upper 50s is usable, anything getting around 60 is preferable. Usually the difference between OK and great is around 2 degrees of bevel angle, the softer, the higher.

 

[bugbear]

You may need to go even a skosh above 30 degrees on a newer chisel that may be on the soft side.

Chisels that are too soft fail by folding, and those that are too hard fail by fracturing or crumbling.

But they both fail, and in both cases the cure is a high bevel (which won't pare so nicely).

The Steel and Heat treatment needs to be "just right", which is why some chisels are better than others.

BugBear

 

[D_W]

Agreed. Soft looks like folded material at the end. Hard looks like material completely missing and unusual failures after coarse sharpening stones.

To some extent, chisels on the soft side can be solved quickly during work by quick touch ups on a very hard fine stone (though you'd rather have a better chisel if possible).

The only chisel I had that failed at no reasonable angle struck 53 hardness on a versitron. It was something a friend offered (to get time on a versitron to find out hardness), and I found out a couple of things:
* the premium makers' chisels are what they say they are in hardness
* the low end japanese chisels aren't as hard as they say they are (which isn't a surprise to anyone who has ever sharpened one on an oilstone)
* the only chisel I had that wouldn't hold its edge reasonably was pretty much saw temper (a newer witherby that was still shiny, probably because of what it was made of).

 

[Sheffield Tony]

From the horse's mouth:

Narex chisels are ground before being hardened, so you may find that edge retention improves significantly after the first couple of honings, this is completely normal and once the first couple of millimetres have been sharpened away you will begin to experience what a pleasure Cr-Mn steel is to use.

 

[bugbear]

From the horse's mouth:

Narex chisels are ground before being hardened, so you may find that edge retention improves significantly after the first couple of honings, this is completely normal and once the first couple of millimetres have been sharpened away you will begin to experience what a pleasure Cr-Mn steel is to use.

Shame they can't grind it away for you. More cost, I suppose.

BugBear

 

[Jacob]

From the horse's mouth:

Narex chisels are ground before being hardened, so you may find that edge retention improves significantly after the first couple of honings, this is completely normal and once the first couple of millimetres have been sharpened away you will begin to experience what a pleasure Cr-Mn steel is to use.

Shame they can't grind it away for you. More cost, I suppose.

BugBear

It's a bit mythical anyway. Anybody new to using a tool finds that "edge retention improves significantly" after a bit of use, basically because they are getting better at it.

 

[James-1986]

My Ashley Iles firmer chisels are great for chopping, they are ground at 30 degrees. Old cast steel chisels by any decent maker will hold up well, going dull rather than chipping and crumbling. I've got some A2 "two cherries" chisels that take a good edge, but are utter crap at holding it whatever angle. They cost too much to throw in the bin so I still have them, lesson learnt.

 

[woodbrains]

It's a bit mythical anyway. Anybody new to using a tool finds that "edge retention improves significantly" after a bit of use, basically because they are getting better at it.

Hello,

Hmm, I wonder what the cause is, when someone very experienced with tools finds a new tool a bit crumbly for the first few sharpenings, then improves? It would have to be some myth!

New tools that are ground before hardening will have a brittle edge for a while, as the thin edge will harden more than the rest of the tool. Ones that are ground after hardening (more usually the case) can have a little temper drawn and be softer at the very edge than the rest of the tool. A few sharpenings will restore both defects, just the same. Ironically, many old tools have similar defects as previous owners quite often draw the temper when they 'fix them up' ready to sell, or many have often been abused. A bit of perseverance will get to the good steel sooner or later.

Mike.

 

[YorkshireMartin]

Following this discussion with interest. I have to say I've found the 25 degree excellent for hand paring. I'd be reluctant to switch at this point in time given the projects I have at the moment, which are both mortice and tenon based joinery that I want to pare by hand due to the length of stock. Long stock really makes a hand saw awkward, for me at least. In any case, I've been finding that I can achieve a tighter joint with hand paring than with sawing which may be counter intuitive or not, I don't know.

I think I'll give the "good" steel chance to come through and see where I am after my next project.

I still have an awful lot to learn.

I appreciate all the contributions.

 

[Jacob]

Just a pedantic detail but "paring" isn't something you'd do with the aid of a mallet.
"Paring" means taking off thin shavings with hand pressure alone, for which 25º edge (or even shallower) should be OK. Rather like planing.
You can't make a mortice by paring, though having made one you could pare the sides.
To cut a mortice you need a 30 to 35º edge which will withstand heavy malletting.
The popular hollow-ground plus micro bevel is the weakest possible edge - OK for gentle paring perhaps (or very fine planing) but not for any heavy work.

 

[YorkshireMartin]

Just a pedantic detail but "paring" isn't something you'd do with the aid of a mallet.
"Paring" means taking off thin shavings with hand pressure alone, for which 25º edge (or even shallower) should be OK. Rather like planing.
You can't make a mortice by paring, though having made one you could pare the sides.
To cut a mortice you need a 30 to 35º edge which will withstand heavy malletting.
The popular hollow-ground plus micro bevel is the weakest possible edge - OK for gentle paring perhaps (or very fine planing) but not for any heavy work.

I should have been more specific. I use a mallet only for the chop cuts. Paring is done with hand pressure. I have a morticer for the umm, mortices :lol:

Since cutting a mortice is similar to chopping shoulders, would it potentially be prudent to have a seperate chisel, at 30 degrees, for that part of the process, then use the 25's for paring out? Just musing.

 

[bugbear]

Since cutting a mortice is similar to chopping shoulders

I've read about an awful lot of variations on processes, but I've never heard of "chopping shoulders".

They're normally sawn (cross cut), and then pared (or shoulder-planed) if the sawing wasn't dead on.

Could you expand a little please - I'm always happy to learn about a new thing.

BugBear