Killing the edge

[Southbound1]

Hi all,
Hope all has a blessed new year! I want to have discussion on killing the edge on a stone.Not saying that they're wrong for doing so , just trying to get different views .Some really accomplished honers do it. I am no cherry at honing but i don't have it all figured out either, not even close. I do understand the mechanics behind it. Whenever you hone on and go up to very high grit synthetic stones and sometimes we may have a razor that is overground or the geometry of the steel cannot support the angle. So this sometimes causes microchips and or wire edge aka white line etc this is caused also by too much time of one side or too much pressure, or to many laps on a particular stone etc.. So when they see this happening they cut off that damage by lightly joining it on the stone.

They then go back to the hones and bring the apex back on the finisher just shy of creating another wire edge. Imo there's probably always a certain amount of wire edge You just got to get a high enough magnifcation and it can be seen. Looks like to me jointing several times during one honing would over time cause too much lost in width of the razor by keep killing the edge. Why not just try and hone away chips or get as much as a burr free edge by simply honing as normal? Again if one kills the edge multiple times during each honing you're taking width off the razor and over time those joinings would in my mind put more than normal wear than normal honing would cause significant loss in width.

 

[silverlifter]

would cause significant loss in width.

I think that is something of an overstatement. Assuming that you aren't removing chips or damage with every honing session, then jointing the edge is unlikely to remove any discernible width over your lifetime.

 

[Legion]

I never kill an edge unless I am assuming there is a problem, and I want to start from scratch. Then I use the side of a glass, not a stone.

 

[duke762]

Is jointing a gentler level of bread knifing? I see a few members jointing to remove a burr or fin. I don't and I only don't because I can't grasp the logic. I think it would be more desirable to prevent the burr in the first place. Some one here mentioned a hone stroke that is supposed to remove a burr but I can neither describe it, or truly understand it, and don't use it either. I would like to learn more.

For instance....my 5k apex is wonderful, after 5k, if to much time is spent on the 8k on up, a fin will rapidly develop. Last progression I did, after the 5k I did six laps on the 8k, and ten laps on the 12k. I still got some sparkles on the apex. Nothing a stropping wouldn't handle but sparkles are baby fins, burrs, and more time on higher than 5k stones makes them much worse. Sneak up on the goal.

Geometry loss would be minimal assuming equal wear on bevel and spine, but over the long term I would venture to say, that overall wear, although minuscule, would be higher than normal.

I usually kill edges by accident......

 

[lightfoot]

I’ve studied this topic quite a bit and as a result I lean towards the use of wooden dowels, thumbnail, buffalo horn scale blanks, & items like that.

Drawing the edge along one of these items can offer a means of evaluating how the edge is coming along and may discourage the development of a false edge before they form.

 

[JPO]

Just by dropping down to a coarser grit you are essentially "killing" a shaving edge, or an edge with issues. For me that is typically down to 6k or 8k in some cases. I does not take that many strokes to remove any issues you may run into at the finishing stages.

If you are using natural stones, like coticules with slurry, you are also "killing" the edge just by honing.

Then you need to adjust your game plane, and try to avoid the same issues again.

There are also some arguments for lightly jointing the edge. However, every attempt at discussing this have not ended well.
It is really not worth the effort, for me at least.

Just try and see how it it works out for you.

Some people do it at different stages just to confirm that the grit you are using in the progression actually put that final edge on, and that you are ready to move to the next grit. It is probably a waste of steel, but the extra steel might not be of significance. Spending too much time at one grit level is also wasting steel.

 

[H Brad Boonshaft]

If you are jointing an edge to remove a burr, micro burr, or flashing, you will remove exactly the same amount of steel or less than if you just “hone” it.

That steel must come off. If you use a piece of wood, or fingernail, or strop it, you break or rip off the burr and then that rough edge must be polished off with a stone or strop.

The benefit of jointing is you make a straight edge and burr free. Then just bring the bevels to meeting at an edge that is already straight.

There is no need to “kill” remove an edge just to make a new one. As said honing with any stone will cut a new bevel and edge.

The largest creator of a burr is the 1k or low grit bevel setting stone. If you grind your bevels flat, in the correct bevel angle and meeting, with stria going all the way to the edge, you will likely have a heavy burr.

Jointing off the burr, a single lap on the face of the stone will remove the burr or make the edge flat and/or weaken the burr so that it will come off cleanly in the next lap. Then bring the bevels back to meeting in less than 10 light finish laps, you will have a straight burr free edge, that you can take to the next stone in the progression.

If you do not joint, you must remove the burr and make the edge straight by honing, the problem is how do you know when to stop honing. Most folks hone way too much. Once the bevels are meeting the edge is as sharp as it is going to get, with that stone. Doing more laps or using more pressure will only thin the edge and or make another burr or an edge that will microchip after a stropping or two.

Jointing is often confused with “killing” an edge, or “Bread Knifing” to remove a chip or edge correction. They are not the same thing. Also Jointing on the flat stone face will remove less steel than jointing on the corner of the stone. Jointing on the stone face spreads the pressure out over a larger area and allows you to use much less pressure and only cut off the burr removing a minimum of steel, and easier to bring back to meeting in fewer laps.

You do not see posts of folks saying I removed a ¼ inch of blade width by jointing my new razor. But the number of posts of new honers grinding razors honing for hours on low grit stones, with lots of pressure, is constant with new honers.

Can one hone a razor without jointing, absolutely. But clearly burr removal and honing too much is an issue for many, that jointing can assist. As said, try it and see if it works for you, if not, Grind On...

 

[alx gilmore]

JPO & others

I designed and developed the "jointing" technique to clear away the loose & folded-to-thin steel that does not aid in shaving hair, for my own experiments. Removing that weak and flopping steel allowed me to then see with my 310x microscope the progress that the next finer stone was, or was not providing. The word Jointing is my own reference, to suggest the similar and same task of preparing wood to be used in joinery where flat and straight is always the first step in any building project. Jointing a razor blade's edge reveals if the edge of a blade is straight enough or if there are voids along the edge (chips, nicks) that might be covered over, out of sight by any folded steel. Close examination with a 200x or greater microscope reveals much that is not viewed with handheld loups. Jointing an edge helps to identify these issues.

Jointing does not straighten a razor's edge, bread knifing a blade edge back and forth on an abrasive will do that. The act of breading knifing reduces the mass of the solid steel with purpose. Jointing a blade merely folds left or right the ultra-thin vulnerable steel before it flakes off. This is a controlled method so that virgin steel is exposed and so I can see the reality of the core metal. A blade may be left convex or concave after Jointing, it is not the intent to of Jointing to challange the core metal. Jointing will not make a razor's edge "shave-ready" but it can be a step to this.

Many men on this forum first rejected the idea of making a slurry with a diamond plate. In Japan, it was common even 15 years or more ago by those same men who were threatening the limits of shaving Port Orford cedar in layers of 4 to 5 microns thin. We here in the US are following in the footsteps of those mostly but not exclusively fellows in Japan, those who live and grow with the host soils and the deeper rock that has provided us these amazingly effective tennen toishi awasedo stones.

Without avarice
Alx

 

[JPO]

This is just one example.
The edge was "killed/jointed" gently on a soft 8k stone after a 12k Morihei edge.
Then it was finished with tomo slurry on a jnat.
The edge performance was really good according to my standards.


Morihei 12k.

KILLED/Jointed edge

Jnat edge

 

[Southbound1]

Interesting ... I have read of guys joining at bevel set then again at 8k. So in my mind if you join/joint 2-3 times everytime you hone that particular razor/edge. Just thinking out loud here. Wouldnt you 'then cause unnecessary wear by joining than you would by regular honing? I do see why it only takes 10-20 laps to bring back the bevels and meeting again. The reason why is all the ground work is already been done. So jointing is not like starting from scratch again, because the edge was previously set and everything is in alignment from bevel
set to midrange . So basically jointing only flattens and strips the weak steel off so you can work with the strong foundation you worked and established at 1k and midrange.


Anytime you hone you don't see reduction in width until the bevel is set, meaning until those two plains are meeting. So jointing 2-3 times joining you're essentially flattening the edge, so you will loose more steel in the long run by having to bring those two plains together again and again?

 

[Southbound1]

This is just one example.
The edge was "killed/jointed" gently on a soft 8k stone after a 12k Morihei edge.
Then it was finished with tomo slurry on a jnat.
The edge performance was really good according to my standards.


Morihei 12k.
View attachment 1773923
KILLED/Jointed edge
View attachment 1773924
Jnat edge
View attachment 1773926

Thats a nice looking edge!

 

[Southbound1]

Jpo mentioned a good point dropping down to say 6k. I agree with that assessment. I do want others opinions on this subject, higher grit synthetics Wander why thats were you see edge failure at the higher grits?? I mean you can hone all day on a 1k and a 4-5k and not see that overly thin apex thats fails and crumbles, at least i haven't . I mean yes you can create a wire-edge at those 'cutters' grits, but its easily honed away at( 1-6k) lower go midrange grits.I have heard of guys saying they can do 100 strokes on a high grit synthetic with no failure.


I must say i maybe not doing something i incorrectly with my pressure and technique. Because i cannot do excessive laps on even a 8k on a thinner ground razor(hollow ground) without experiencing edge failure. There also bevel angle and steel quality in the equation along with the grind thickness Imo if you keep the grits tight in progression and do all the work correctly at the lower grits then by the time you get to 8k and above very little time is required on the higher grits . Sham (the Russian guy ) i learned something from him: If you come off of the 4k and go to the 8k and you see a lot of swarf on the 8k in just a few strokes then you need to go back to the 4k. If you did the correct work at the 4k then you should hardly see any swarf on the 8k. I used to believe that one could do excessive laps on higher grits, until i learned and grew with my honing. Still learning, still don't have it all figured out


These higher grit synthetic stones have a lot of horse power. So this is just me, if i do all my ground work correct(set bevel) i am ready sharp, 98% of my work is done. As I move up i am making a smoother 'edge plain'/apex. So i see no point in doing excessive laps on a 8k and above. Imo on a thinner ground razor 10-15 laps is enough for a 8k if you done everything right, because these stone are fast and again 98% of the bevel is done. Again i cannot do 100 laps on a high grit finisher. I can but the outcome will not be satisfactory. I do believe why people say higher grit synthetics give a harsh edge, its not the stones fault it maybe user error, we 'all have experienced' that.


I have read that higher grit synthetics edges degrade at a faster rate (i have to agree, but i dont know if my assessment is correct) Maybe they degrade after say 5 shaves or fail on a very bumpy linen after say a shapton 30k or a Gok20 is because we did too many laps on the higher grit synthetics. In my mind a almost perfect execution on a synthetic progression an edge should not degrade no faster than a natural edge. Really to me natural stones are easier to hone on verses synthetic.

 

[Gamma]

I consider joining and edge killing to be pointless.
When I put a blade on the stone, the edge makes contact with the stone, and the grit abrades whatever it is in contact with. The act of 'killing' the existing edge happens by default, 100% of the time, by simply being in contact with the stone's surface. For regular home honing, killing it twice makes no sense.

The one exception is if I am doing a demonstration and I want to remove the peanut gallery's ability to argue about things they really don't understand.

A lot of the old-school 'edge killing' didn't really kill anything, it just rolled the edge a bit and could probably be stropped out. But that's another story.

Joining is the act of wiping out work so it can be done again. Personally, I prefer to just do it right the first time. But if you need to redo something, just jumping back a stone or two does the exact same thing and it works perfectly.

That said, anyone is entitled to do whatever they want with a blade they own. To each their own.

 

[cugel]

I have not found it necessary in razor honing. In knife sharpening, a burr is typically raised and sometimes removed with what could be considered "joining" by some.

 

[JPO]

I do want others opinions on this subject, higher grit synthetics Wander why thats were you see edge failure at the higher grits??

There can be allot of different reasons why the edge starts to fail at higher grits.
One reason is incomplete ground work at bevel set and mid-range. In allot of cases you can trace back small chips to deeper bevel set striations. Even if the striations are not visible, the damage to the steel extends further then the dept of the striations.
At say 6-8k the edge should already be close to finished. The amount of time spend after this on fast higher grit synthetics should be quite short. Trying to make up for work that should have been done at lower grits on higher grits is usually problematic, for different reasons.

These higher grit synthetic stones have a lot of horse power. So this is just me, if i do all my ground work correct(set bevel) i am ready sharp, 98% of my work is done. As I move up i am making a smoother 'edge plain'/apex. So i see no point in doing excessive laps on a 8k and above. Imo on a thinner ground razor 10-15 laps is enough for a 8k if you done everything right, because these stone are fast and again 98% of the bevel is done.

Yes, these higher grit stone do have allot of horse power. However, if the apex is ragged they will most likely thin the edge too much before the apex is able to be refined.
So, if someone only had a good 8k and a finishing stone, and they wanted to maintain a razor without buying a full set of stones there are techniques, like jointing that can be used to utilize a minimum set up of stones. It is much faster to add lower grit stones though.
As the edge wears during use the steel gets damaged. Plastic deformation leads to strain hardening, which leads to a more brittle steel. When you hone the razor this steel needs to be removed. If you want to get by with just some higher grit stones you can keep the edge from failing prematurely by jointing the edge a few times, and recreate the edge again.
The edge also wears unevenly along the edge. The middle and the tow wears faster then the heel on my razors. So if you want the edge to form at the same time along the length of the blade you need to take this into account. Jointing also evens out this. Honing on lower grits (i would say below 8k) does the same.

In my mind a almost perfect execution on a synthetic progression an edge should not degrade no faster than a natural edge. Really to me natural stones are easier to hone on verses synthetic.

This will depend on the type of natural stones you use also.
In my opinion part of the reason jnat edges are so good is because of the how they cut the steel.
If you want to extend the fatigue life of a weld you can hammer peen the steel. This creates compressive stress in the weld, which slows down the crack propagation, and reduce tensile stress. The beat blasted jnat edge can to some degree be compared to the hammer peened weld.
This also creates some work hardening, which in theory will change the steel properties a little. This is a fine balance, because it also increases the brittleness of the steel.
A synthetic stone have hard and sharp abrasives, which leaves sharp striations. The shape of the striations is important because they introduce stress concentration at every valley of the striations.



Just do some testing your self.
If you have razor with a good bevel that might need a touc-hup, gently joint the edge on e.g. 8k, and bring it back with that stone. You can do this twice, but you should not need to. Then you use your finishing stone, by only doing a maximum of 10-15 light strokes.
This technique requires a light touch, and maybe some practice. The first time you try it you will probably dull the heel and the tow too much.

If you have a complete set of stones, and do small enough grit jumps there should not by any reason to kill the edge multiple times. Small grit jumps is probably the simplest way to hone a razor. However, someone who don't own allot of razor might not need to own a complete set of stones, in my opinion. They certainly don't need to learn to shave off a 1k edge.

 

[Steve56]

Wander why thats were you see edge failure at the higher grits??

The most common reason that I see (barring defective steel) is that the bevel angle is too low, sometimes apparently by design. Remember that when many vintage razors were made, there weren’t any high grit stones so they didn’t have to plan for them. Tape has always stabilized the bevel.

I currently own two razors, both thin 7/8 - 15/16, an ERN and a Bartmann. Both have bevel angles at 16 degrees or under and are unrestored. They have spine widths in the 0.220” range, where a Filarmonica 14 spine is always around 0.250” when unworn. One struggles to take an 8k synth edge and the other will not take a good finish4d JNat edge. Two layers of electrical tape on the spines fixes them.

I’ve seen this before on German razors in good condition and was beginning to think that this instability was not a coincidence because of the spine width, so I started asking around to other experienced honers. Scott L said that he’s also seen this multiple times on vintage German razors and believed that the razors were made with too-low angles so that after a lot of maintaining on pasted strops, the razors would actually shave better than if manufactured with a correct angle! And they didn’t have to worry about >8k stones. Speculation yes, but interesting speculation.

Another I’ve seen is Japanese, same kind of edge failure but the angle was OK. It has been restored, so I suspect that the temper had been ruined. A couple of layers of electrical tape (adds about 1 degree of bevel angle per layer) fixed it too, but it ended up at almost 19 degrees, which is not what a JRazor should be.

 

[H Brad Boonshaft]

So basically jointing only flattens and strips the weak steel off so you can work with the strong foundation you worked and established at 1k and midrange.

Yes.

So jointing 2-3 times joining you're essentially flattening the edge, so you will loose more steel in the long run by having to bring those two plains together again and again?

Nope, because you will remove exactly the same amount of steel, the burr must be removed and if you break off the burr, you will need to straighten out the jagged, broken edge. You may actually remove even more steel. Remember we are talking about microns of steel.

If you make a burr, how you remove it will determine the quality of the shave. Anytime you hone steel on stone, you will make a burr.

 

[Bayamontate]

Jointing, killing, I do neither. I’ve always seen killing the edge as the honer needing confirmation they’ve actually done something or having to prove to someone else they’ve done something. I’m too old to play those games, no thanks.

 

[Steve56]

I don’t join or kill edges anymore either. I just found that it wasn’t necessary or produced anything that proper honing wouldn’t produce.

Maybe we’re talking about (at least?) two different things here. If I set a bevel via the burr method (I don’t), then I have a folded over burr made of weak metal. I can scrape that off on a stone, wood, cork, whatever, but I can also hone it off using light strokes flipping the edge each stroke. Either way, I’m in the same place I think.

A honyama burr from a finisher seems to be a different animal. This tiny burr seems to depend on the steel, stone, technique etc, but there seems to be many ways to remove it. Mr Mizuochi and Iwasaki used a pasted strop to remove it. Mizuochi also implied or said in one video that it could be stropped off though others disagree.

Alex Gilmore taught me years ago that a few strokes on a dry hone after finish honing would improve HHT and it does. I use the strokes on the dry hone that Mizuochi used on the diamond strop in his videos. Later on, I was talking with Takeshi Aoki about dry honing improving HHT after finishing, and he immediately began talking about honyama burr removal. I don’t use a microscope so I can’t see the honyama burr, but something happens as a result.

I’m wondering if plain slick cardboard like the inside of a cereal box would work, or newspaper. People have stropped on cardboard for decades. A double/triple layer of newspaper would have some things in common with Iwasaki’s CrOx fabric strop and Mizuochi and Iwasaki the younger’s diamond strop, they’re all flexible enough to hit the apex at a steeper angle than a hone and they’re abrasive.

I have not tried it yet, but suspect that adding a layer of 1mil Kapton and hitting the finisher for 2-3 light strokes would also do it. Give it a try Mike!

Interesting discussion.

 

[Wid]

I will joint an edge here and there. Especially if there is some micro pitting and if so I might do it multiple times. If I’m going to a whole new progression I will sometimes do it, just to confirm the edge is true to what I want.

As far as I can tell it is such a small deal it’s hard to tell the difference if one could at all. There is no right or wrong here as long as the final edge is a good shaving one.