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Edge retention with steeling (i.e. Kyley's awesome experiment)

Posted by CliffStamp 
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Edge retention with steeling (i.e. Kyley's awesome experiment)
October 14, 2014 11:42PM
Awhile ago Kyley asked about edge retention if you steeled the knife, in particular if you used his nitrided rod. Now there are a few things which are well known but they lack exact answers and there are a lot of questions which have not been addressed at all. The conflict is basically about how much of edge loss is by deformation vs fracture and wear and how much is the edge retention loss after steeling, i.e. how much does the cold work in steeling weaken the edge?

A basic few outlines of experiments are :

-look at a very low stress/wear cutting (hemp) vs a fairly high stress/wear one (cardboard)
-does carbide volume significantly affect anything

Now again there are a few things you would suspect right away such as :

-steeling would be more beneficial on the hemp vs cardboard
-a low carbide steel would benefit more than a very high carbide steel

However what are some numbers? How much hemp can you cut with repeated steeling, 2X the amount, 10X the amount, 100X the amount? before you can not get high sharpness on steeling and the edge retention is severely compromised.

The same questions can be asked in regard to carbide volume and what happens if you do harder and more abrasive cutting (cardboard or even worse carpet). How much worse is cardboard vs hemp, or carpet vs cardboard?

I did a simple first run experiment this evening, I used :

-Spyderco Lum Chinese
-6.5 dps edge
-15 dps micro-bevel, 600 grit DMT
-steeled at 20 dps

I just ran the edge until it had < 1.5% optimal sharpness, did very light steeling (just enough to get optimal sharpness) and repeated everything.

The good news (or bad news depending on perspective) is that if you are cutting hemp then it looks like you can steel for a LONG time. I did five runs and had no issues getting back to close to ideal sharpness and had only minor loss in edge retention.

Here is what the edge looks like after five steeling runs (6 runs in total counting the first one) :



The small bevel above the red line is the steeling bevel, the bevel above the green line is the dmt micro-bevel. Note the steeled edge is more polished than the DMT bevel which would be expected. At this point if you scan along the edge it is starting to pick up chips but they are still rare enough and small enough that the are still in the steeling bevel.

I will do another five runs to see if the performance starts to decrease, at this point it looks like possibly the small amount of burnishing is offsetting the small wear and deformation during blunting. Now before everyone throws out your stones, not all blunting is like this, on harder cutting for example this won't happen as there will be significant wear and fracture.

--

Now there is a significant downside to this experiment data stability wise though. As I only sharpen once and then do ~10 runs, if the initial sharpness / edge is off this will bias every run that follows it. Thus even though it looks like a lot of data, it is only as stable as ONE run basically. Thus I will have to repeat all of this jazz at least three times to see if it is stable and if any patterns hold.
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 15, 2014 11:34PM
Here is the first set, the zero run is with the DMT and then the runs which follow are the steeling runs :



Again, as all of these runs start from one single sharpening this really isn't that stable and so for now a few general observations :

-the edge retention tends to decrease with steeling
-however it is still at a functional level
-the steeling was less than 10 seconds each round
-the total edge retention was ~5X the first run and the knife still is responding to the steel

As a general conclusion it seems safe to conclude that it is likely that on cutting soft material like hemp it is probable that even steels such as 420J2, H13, etc. the steels which most would argue are almost useless for edge retention would easily last longer between sharpening than the best performing blade steels if the first group of steels are used in this manner.

Now of course you could day "Well hey, can't you use the cKc hone on M4 as well?" . Well first of all I am not sure it is obvious that this will work as well as on that kind of blade material but even if it does what is the advantage if you are using the hone because it literally takes 5-10 seconds 5-10 seconds to get back to optimal.

As for sharpness, even at the end it was still possible to get back to near optimal in sharpness. But some care has to be taken in how you are using it. See that part at the end of the runs where it jumps back up at the #10 run, that is because I really refined the technique in that run. The ideal technique I found so far is :

-use the swirled (textured) end first and finish on the smooth part
-go as light as you can and do lots of passes vs a few heavy one
-alternate passes as much as you can (don't do all one side, then all the other)
-don't over steel, stop as soon as you reach high sharpness

I checked for shaving every five passes and stopped using the textured part as soon a it would shave with barely touching the skin and then do 5 pps on the smooth side to end. I was just judging 20+ dps by eye, if you were jigging at an exact angle then it would be faster and ideally just go slightly above the edge angle. I had to use a significantly higher (5 dps) just to ensure I was on the apex exactly.

As a side note, knowing results from previous trials that angle itself is likely the reason why the steeling edge retention is dropped. As it was being steeled at ~20 dps but the original edge was at 15 dps the edge retention would be expected to be reduced almost immediately as the apex angle increased.

--

Now this has to be repeated at least a couple of times to get the scatter and hopefully consistent performance and then it might be interesting to see what happens on the lowest end with a 3Cr13 steel. Then the next thing would be to see if the same thing can be done on cardboard and I don't think it will be that has a much larger rate of wear and can actually damage the edge by fracture - but still some response is likely.



Edited 1 time(s). Last edit at 10/16/2014 12:01AM by CliffStamp.
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 16, 2014 12:05AM
Is this abrading the edge or just realigning it?

If so, does the edge thickness play into it at all...for instance would the results be as strong on a thicker chopper edge (let's pretend it was done on clean would, or does even that fracture the edge too much) or a tactical edge used in the same low abrasive cutting? I'm thinking there would be a lot more steel there to abrade / push around and so it might take more strokes which in turn might create more fatigue in the edge.

_______________________________________________________________________________________________

Always in search of a good choppa'
KWB
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 16, 2014 03:19AM
That was my findings, although my wasn't as I depth as yours. The important thing I like to note is the 5-10 seconds to get the edge back. If you just wanted to keep cutting you could just keep touching it up. Now obviously overtime the results will degrade to the point where it isn't useful any more but that would be quite a few times. Unlike stropping it doesn't take away from the agression at least not to a meaningful degree.

The only thing that could be improved is making it a little longer for big blades.

Contact 570-486-9095
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 16, 2014 12:13PM
Quote
C Amber
Is this abrading the edge or just realigning it?

There has to be some adhesive wear and likely even abrasion on the textured surface but it is very mild when used with low force (as in just touching, only what is needed for control). The extremely rapid restoration of the edge has to be deformation based, I can't see it abrading it that fast - especially given a high carbide steel and a very smooth surface. I can also check the edge thickness directly (though with poor measurement/resolution) with some 50X magnification shots right into the edge the next time.

Quote

I'm thinking there would be a lot more steel there to abrade / push around and so it might take more strokes which in turn might create more fatigue in the edge.

The apex when worn (to a certain point of dullness) is the same thickness regardless of the edge thickness or even edge angle.

Other materials will raise some interesting questions as chopping wood puts a lot more loading onto the edge and will expose loss of strength/toughness and cardboard (and carpet) will bring actual heavy abrasion and even fracture into play. With those I suspect the utility will be lowered.

--

At this point though another point has to be made, the edge I am using is set with a 600 grit DMT which is fairly coarse/rough in general, similar to a fine India. In order to keep this type of slicing sharpness you have to go light on the steel, I did a final run using heavy force and while it brought the sharpness back quickly (as in it shaved), it lost all slicing aggression. I suspect that this actually made the steel flow plastically at the edge and removed all the "teeth" from the DMT finish completely. At this point it also became very difficult to near impossible to use on the hemp, it was like trying to cut with an over buffed edge. There was little utility in slicing, you basically just had to do a push.
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 16, 2014 10:16PM
Blah, I was looking forward to doing multiple runs because I wanted to see how that pattern would develop but such is not to be. This is what happened when I reset the edge and tried to do another run :



+



That is only after 7 cuts into the hemp. I ground the edge off completely and tried again :



and the damage set in right away again.

--

Before anyone jumps to a general conclusion, the angles I am using on these knives which are under the micro-bevel are very low, they are basically right at the point of having necessary strength in use.

What is likely happening is that all that repeated steeling is just generating fatigue and just like when you bend a fork back and forth, the damage goes deeper than the fold line. When I sharpen the knife that edge is forming in that steel and thus those premade cracks fracture easily. It likely didn't help that the last steeling round I used heavy force to see what difference that made.

It would be interesting to try all of this again with a steel with a much lower carbide volume as VG-10 is ATS-34 class which means it is full of those very large chromium carbides and that isn't the kind of micro-structure you want for fatigue resistance.
cKc
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 17, 2014 07:40AM
Very interesting.

Victorinox grade steel might be a good choice

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 17, 2014 02:14PM
There are a lot of questions generated here and some of it ties into a lot of conventional wisdom such as how some so many people avoid steeling Japanese knives when it is so common on Western knives? Are the Japanese really so ignorant that they never thought of the idea of a burnishing type tool or is sharpening such a strong cultural bias?

Note as well that I was doing this very light, if you press harder to speed it up then the onset of damage is likely less. But in general no one really promotes steeling high carbide very hard steels anyway. It is traditionally used on the 3-5Cr13 class steels which are leagues more chip resistant.

I think I really need to try this again with one of those steels because I simply can't see them having that kind of fracture problems as there is nothing in the steel to allow them to fracture in that way.
cKc
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 05:42AM
Can you try with the Mystery-X? it might be an excellent candidate for this

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 03:32PM
Yeah, I am in the middle of using the EE Chef (3Cr13) now.

The interesting thing to me is how sensitive the edge retention/performance is to the starting point. Now maybe this is obvious as it is just sharpness after all, but how many times when you see people steeling or talking about it do they do it in any kind of controlled way vs some kind of ninja-swordship display.

In order to get the best results then the steeling should produce an extremely high sharpness, past the ability to shave arm hair but be at the point where it does it by barely touching at a minimum. The basic procedure isn't complicated :

-sharpen on the textured side, alternating passes, very low force (just make contact), unless the edge starts to shave
-5-10 pps on the smooth side, very light again

This should allow the edge to shave with the barest of contact against the skin. The edge retention is easily double (or more) if you steel until the edge just starts to shave or requires significant pressure. And if you do the kind of hacking/hard contacts which are common then the edge aggression is seriously reduced and edge retention is minimized .
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 04:34PM
I'm very interested in your test results on this Cliff.

I gave it a bit of thought, and then talked to my Dad to confirm, but he very rarely sharpens his knives, but he does steel them often. I remember watching him do it, and he is very slow and deliberate, and according to him he uses "barely any pressure." He just has a few old butcher steels, and it definitely keeps his kitchen knives sharp and improves their sharpness after HE STEELS THEM.


I'm also interested in how it behaves with Kyley's Mystery X steel as well as 3Cr13.

Is steeling likely to be more or less beneficial on thicker edges, or does it matter? Would the thicker edges be less likely to be weakened than thinner edges? I would think so... but things don't often work out the way I think they will.


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 07:44PM
Quote
Chum


Is steeling likely to be more or less beneficial on thicker edges, or does it matter?

Steeling is only going to affect the apex so the edge thickness can't have any influence that I can see.



Here is the first round with the EE Chef which is a $1, 3Cr13 , knife. Again :

-there is a decrease in edge retention with steeling
-the edge retention is however still at a functional level
-the total edge retention is much larger than the as-sharpened edge

It seems to me that the large and immediate difference isn't because of steeling specifically but is a combination of possibly two things :

-the apex angle is larger when the knife is steeled
-the finish of the edge is much finer

both of which would reduce edge retention. It seems obvious then that the next thing to do, after repeating this all with this knife at least once more would be to look at if the starting edge was finished on a higher polish.
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 10:10PM
Quote
CliffStamp
Steeling is only going to affect the apex so the edge thickness can't have any influence that I can see.

Oops, I meant apex.


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 10:27PM
I am not sure what you mean actually, the apex is the part which is being steeled. Are you asking if it matters how dull you let the knife get as the apex thickens as the edge dulls?
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 10:33PM
Quote
CliffStamp
I am not sure what you mean actually, the apex is the part which is being steeled. Are you asking if it matters how dull you let the knife get as the apex thickens as the edge dulls?

I'm mixing up my terminology... what I'm talking about is the micro bevel, which I associate with the apex. If the micro bevel is 20dps vs 10dps what will the effect of steeling be?


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 11:07PM
The current angles are :

-edge, ~5 dps
-600 DMT microbevel, ~15 dps
-steeling, ~20 dps

Are you asking what happens if you move the steeling angle closer to the micro-bevel angle, or keep the steeling angle higher and move the micro-bevel closer to 5 dps, or change both the steeling and micro-bevel angle and make them closer or further apart?
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 18, 2014 11:48PM
Quote
CliffStamp
The current angles are :

-edge, ~5 dps
-600 DMT microbevel, ~15 dps
-steeling, ~20 dps

Are you asking what happens if you move the steeling angle closer to the micro-bevel angle, or keep the steeling angle higher and move the micro-bevel closer to 5 dps, or change both the steeling and micro-bevel angle and make them closer or further apart?

Why would the steeling angle be different thant the microbevel? Aren't you just trying to push the metal back to its original state ie. resetting the microbevel after it has been deformed.


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 03:47AM
Quote
Cliff Stamp
I was just judging 20+ dps by eye, if you were jigging at an exact angle then it would be faster and ideally just go slightly above the edge angle. I had to use a significantly higher (5 dps) just to ensure I was on the apex exactly. 

Remembered reading this bit, so figured I would highlight it.

-Nate
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 12:21PM
Chum,

As noted in the above, if you don't jig sharpen then you will want to steel slightly higher to ensure you actually hig the apex.



After two runs there seems to be no sign of the fracture seen in VG-10 which would be very surprising in this steel given the low carbide volume and over all very high toughness/ductility. The edge retention is easily 5X that of the initial and the knife is still responding to the steel.



This is the knife at the end, note the steeling bevel has basically over taken the actual micro-bevel of the DMT stone. At the end it takes about 40 pps on the textured side to get the sharpness back to optimal. However I discovered that keeping the steel on the edge and not lifting it can cut this in half, there is no need to lift the knife off. As these passes can be done fairly fast (but again have to be very light) it still is less than 10 seconds to steel the edge even at the end.

I want to repeat this one more time just to make sure that there isn't a fracture issue, but it seems kind of obvious that there is a very strong case for this kind of steel for a lot of use if the edge isn't getting damaged or excessively worn. This steel and others like it are :

-very corrosion resistant
-high toughness / ductility
-very high edge retention (with steeling)

In fact the latter is higher than any steel not-steeled, again talking about low stress cutting like hemp. They are also very easy to sharpen on the simplest of stones :



That is off the Suehrio, note it has none of the chipping seen on the S30V when apexed with the same stone.

A curious question is how do AEB-L and White/Blue steel respond?
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 01:52PM
I have a Murray Carter gyuto in white steel that I wouldn't mind trying to maintain with a steel for a while to see how it responds. Any tips on where to find a smooth steel? All I ever see locally are the heavily grooved steels or the diamond abrasive ones...
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 09:14PM
Quote
ianevans
Any tips on where to find a smooth steel?

Lots of places sell them on line, even glass rods are becoming popular, they are commonly sold with stropping supplies.

--

This is three full runs :



I am becoming more convinced that sharp initial drop is more of an apex finish/angle than steeling change as the change in edge retention from that point forth is very small .

The reason for the heavy scatter is that the edge retention you get from steeling is really sensitive to how you apply the edge. If you go too far and over steel and weaken the edge you can't restore it as there is no way to remove that bit of over worked metal. But if you don't go far enough then the apex isn't well formed and the sharpness isn't there and it cuts at a mediocre level which also gives poor edge retention.

In practice when you are not trying to study some small effect here as I am, you just steel for 5 s, check the edge and see if you need another round. If you go a little too far and the edge collapses too quickly in use, well then you just do another 5 s .

Here is the initial edge :



After the last steeling run, note the heavy deformation (large white lines) :



Note as well how all of the DMT scratches are long worn off, one of the reasons why I don't polish edge bevels in general because even something as mild as hemp will reset edge finishes quickly.
KWB
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 09:43PM
What is your relationship between polished bevels and peak sharpness?

Contact 570-486-9095
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 09:54PM
Quote
Apophis
Quote
Cliff Stamp
I was just judging 20+ dps by eye, if you were jigging at an exact angle then it would be faster and ideally just go slightly above the edge angle. I had to use a significantly higher (5 dps) just to ensure I was on the apex exactly. 

Remembered reading this bit, so figured I would highlight it.

OK, I get it. Interesting to note what Sal said (jig) ...

Quote
Sal
John Juranich produced a pair of hard highly polished steel rods as part of his offerings. Don't know if he still makes them. I removed them from their holder and use them in the slots of our white ceramic triangles at the same angle just used (30 degrees in my case). Interesting results. They do feel a tad sharper and seem to stay sharper longer. I've thought about producing a pair of highly poished hard smooth rods as an accessorhy to the Sharpmaker.

link: Spyderco Forum


I was also reminded of this video...






Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 09:55PM
Quote
KWB
What is your relationship between polished bevels and peak sharpness?

I don't know exactly what you are asking.
KWB
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 19, 2014 09:59PM
What do you think peak sharpness is attained? How much benefit do you gain from say 1200 to mirror in terms of pure sharpness disregarding what is going to be cut with it.

As 400 won't shave to well but cuts rope better than 1200.

Contact 570-486-9095
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 20, 2014 05:11PM
Quote
KWB

...

As 400 won't shave to well but cuts rope better than 1200.

There is a lot going on here, to start we have to separate :

-sharpness vs cutting ability

-sharpness on a push vs sharpness on a slice

The next is likely a little controversial, if you have a 400 grit finish that won't shave and a 1200 grit finish which doesn't cut rope well neither of them are sharp.

Here is a simple experiment :

-take a piece of 1/2" rope (or anything similar)
-sharpen an edge with a 100 grit abrasive (should easily shave)
-cut the rope and record the force you need to apply to make a cut in a 2" draw

Now until you get bored :

-increase the edge finish and repeat

This is what should happen :

-the force will start out fairly high because it simply takes a lot of force to pull that very coarse edge through the rope
-the force will decrease to a minimum at some point
-as you increase the polish further the force doesn't increase but it changes to being more of a straight push
-at some point you can do a push cut with the same force as you do a slice

If at any point :

-the edge fails to cut then it isn't over polished, it is just rounded off
-if the edge doesn't shave, it isn't because it is too rough/coarse, it simply isn't sharpened

In order to get a complete measure of sharpness you need both the push cutting and slicing aggression. However for a total performance view you also need the edge retention. For example a 1200 DMT finish likely will have both a higher push cutting and slicing sharpness than an XX-Coarse DMT. However the latter will have much better edge retention on slicing (worse on push cutting).
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 20, 2014 05:19PM
For some specific numbers, I can slice a piece of 1/2" hemp with about 4-5 lbs on a 2" draw. I can do this on a 600 DMT or similar. As the polish increases the force doesn't significant decrease but the knife will just stop doing a slice and at some point it will basically push right through the rope as you apply the force. If you measure the sharpness :

-at 600 DMT the push cutting sharpness is about 25-30% of optimal

As you increase the polish this steadily increases however the slicing sharpness doesn't really change. However if you decrease the grit then both the push cutting sharpness and slicing sharpness will decrease - but the edge retention on a slice will dramatically increase.

For a lot of utility use I use a 600 DMT finish as it has solid edge retention on a slice and isn't poor on a push. However for wood cutting (out door use) and kitchen use I jump way up to the MXF DMT, or some kind of 5k+ waterstone for larger blades as push cutting is critical and slicing isn't (in general).
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 21, 2014 12:54AM
Ah this is stupid, I don't even really care how steeling works as I don't do it but I am curious enough now I have to do a few more experiments. The next time you have an idea Kyley I am going to pretend you don't ask it.

I think I have figured out a way to steel an edge and not have that initial sharp drop in edge retention :



That is what the edge looks like after a steeling run, note it doesn't have that significant deformation in the runs above. I am not confident I can repeat it yet, need to do it at least once more.



In case that doesn't look like a lot of hemp, it is deeper than that knife is long :

KWB
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 21, 2014 01:57AM
I understand what you are saying but what I mean is both edges are equally sharp 400/1200. Could you say that the 1200 is sharper as it is a higher finish thus the apex is much cleaner. I'm thinking of the video you did between finishing sharpness as wood workers use and a coarse utility edge.

1200 will push cut better than 400 but 400 will have more aggression. But would you disagree that the sharper the blade the higher the finish?

Contact 570-486-9095
Re: Edge retention with steeling (i.e. Kyley's awesome experiment)
October 21, 2014 12:03PM
Quote
KWB
[...]
But would you disagree that the sharper the blade the higher the finish?

Simply increasing the grit finish doesn't increase the sharpness because sharpness isn't defined in that way.

There is an ISO standard on sharpness, and there are materials definitions which depend on things like the rupture pressure. They all mean the same thing essentially and it is exactly what people mean in lay terms :

-a sharper apex will take less force to make a cut, or less draw length to make a cut under a given force

A 1200 grit edge will be sharper on a push cut than a 600 grit edge. However, depending on the material, it likely isn't sharper on a draw cut but will have significantly lower edge retention.

This is a semi-decent 400 grit edge :





There are a lot of misconceptions on sharpness because someone will do something like try to cut a tomato with a polished edge, fail, and then say something like "a coarse edge isn't sharp but it cuts a tomato better". How are you defining sharp if making a knife less sharp (more dull) makes it cut better. The coarse edge in that case is sharper when using a draw cut than the higher grit edge. Given that the higher grit edge is slipping on the tomato it is likely rounded and simply not sharp.

Murray Carter's 3-finger test is useful here, knowings it limitations and not treating it as some kind of absolute but a sliding scale. Many people are very surprised when they try it and find that the knives they consider to be sharp to fail that check strongly. I suspect this is just a modern thing because of the common use of buffers, ultra-high carbide steels and just lack of work with knives and more collectibles.



Edited 1 time(s). Last edit at 10/21/2014 12:55PM by CliffStamp.