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Sharpening and Knife Lifetime

Posted by me2 
me2
Sharpening and Knife Lifetime
June 01, 2014 07:26PM
Since the cutting trick knife is taking so long to reset the bevel to 17 dps (it is about 22 now from sloppy hand sharpening), I thought I'd try another mystery that has been bugging me. Just how much steel gets taken off during sharpening?

I have the RADA Santoku which has been sitting dormant for a while. I'm gonna try and sharpen it about 10 times per night for the month of June. At the end, that will represent nearly a years worth of daily sharpening. The procedure will be as follows:

Destress/deburr: cut into the stone at 90 degrees 3-4 times
Shape: shape the edge at 17 dps on a King 1k water stone until it no longer reflects and reaches 40 passes per side. A small burr will likely be present.
Repeat

I'm not looking for a sharp edge or anything like that. Just shape and repeat.

I measured the blade width at the very heel of the dropped edge. It started at 1.31" wide. My calipers only go to 0.01" graduations, so I'll estimate anything in between.
Re: Sharpening and Knife Lifetime
June 01, 2014 07:35PM
Ideally sharpening doesn't remove any metal (width wise), that is just achieved in the use. The prominence and over use of burr-based sharpening changes this though by it forces over grinding.

What is critical is what you do to the edge to make it ready to be sharpened as obviously you have to do something to repeat the sharpening to dull it.

--

If you assume a sharp edge is about 0.5 microns thick, a 20 micron wide edge, which is about the point you can see it, is extremely dull, on the order of 1%. If you sharpen before then, the use is likely thickening the edge to 5-10 microns.

If your edge angle is low this means 10-20 microns of steel were removed in the blunting (width). Ideally sharpening 100 times will remove ~1.5 mm of metal, any more than that is just over grinding.
me2
Re: Sharpening and Knife Lifetime
June 01, 2014 08:10PM
I haven't looked into it at that level. This is to explore how much is removed with burr based sharpening, because that also carries on to the very common promotion of stropping frequently. Even using a 1k stone, a burr is raised in just 50 passes per side (pps). This takes very little time, maybe 1.5 to 2 minutes for all the passes, rinsing the stone, and swapping sides with the sharpening block. People, particularly on the Hinderer forum, were very adamant about removing the least metal possible, even when using 25 dps angles.

After 10 sharpenings, about 0.01" has been removed from the width at the heel. A note on the measuring - it is tricky to make sure everything is aligned properly when doing this just with the knife in one hand and a caliper in the other. Without using the metal caliper at work, I'm not confident in being able to reproduce measurements to anything smaller than 0.005". Ideally, this would be done with a spring caliper with rigid edges, but I have a plastic dial caliper with pretty flexible jaws.

After 10 sharpenings, the width is 1.30" at the heel.

Some changes/alterations:

The edge was given 4 destressing passes into the stone before each sharpening. The flat on the edge was visible in good light and was maybe 0.001" wide. I used 50 passes per side to sharpen, and a burr was raised after each round. This burr was large enough to feel by stropping on my arm, which is less sensitive than my head hair. I typically can't feel one of like this with my fingers or finger nail. I'll try to drop the number of passes to 40 and see if that removes the flat on the edge without raising such a big burr.

On another note, I have noticed that even with destressing the edge, too few passes makes getting a very sharp edge problematic. For instance, on the Hinderer from the pass around, sharpening at 22 dps, a burr was raised after just 20 pps on the 220 grit stone after destressing the edge following cardboard cutting. However, destressing again and repeating seemed to give a sharper edge. This was not measured at the time, as I was using the ability to slice a plastic grocery bag as the test for sharpness, not thread push cutting.
me2
Re: Sharpening and Knife Lifetime
June 03, 2014 07:56PM
OK, round 2. I skipped last night. This time I lowered the passes to 30 pps instead of 50. After the first round, 50 seemed excessive. Tonight's session showed I was right and 30 pps on the King 1k stone proved sufficient to remove the flat and form a small burr. However, the reduced number of passes paid off, as the blade width was only reduced by less than 0.005" this time. I'm giving a rough estimate that it's around 1.297"
Re: Sharpening and Knife Lifetime
June 04, 2014 04:10PM
sweet! so you are measuring both width of the edge and width from the spine to edge?
me2
Re: Sharpening and Knife Lifetime
June 04, 2014 06:29PM
Not width just yet. The primary grind on this knife is just buggared. It's difficult to characterize other than to say somewhere between the spine and edge, it starts to taper from full stock (1/32"winking smiley down to the edge. So far I'm just measuring the blade width.
me2
Re: Sharpening and Knife Lifetime
June 04, 2014 08:48PM
3rd round complete. The width dropped to 1.288". There was a slight change in procedure, so this could be the reason for the added metal loss. I switched from the King 1k to the Norton Economy Coarse. The reason for this was I wanted to lower the number of passes to 20 pps on the King, but at that point, I spend more time rinsing and cleaning the stone than I do sharpening, so I switched away from the water stone. I used Cliff's scrubbing shaping method, giving the blade 3 to 5 scrubbing passes down the length of the blade with fairly light pressure. The deburring was the same, 4 passes into the stone, though the stone was a coarse Norton. I'll try this again tomorrow night and see if I can keep the loss to a minimum and limit it to 3 scrubbing passes per side. I don't normally sharpen this way, but I didn't want to spend 30 minutes to only have 25 of it be messing with the stone. Basically, until I get some practice at this method, there will be more metal removed than I'd like to see.
Re: Sharpening and Knife Lifetime
June 05, 2014 03:36AM
Changing stones and techniques is a good thing in this test me2. Considering you are creating a lifetime of sharpening in a month. It would stand to reason that you would be doing different things to sharpen the knife as your knowledge, interests and available stones change.
Do some with the sharpmaker as well. Maybe an evenings worth of sharpening on the back of a dinner plate. I know many of my knives get touched up this way. What about a steel?

Just thinking aloud.

Great test.

How many overall sharpenings are we at now?



Edited 1 time(s). Last edit at 06/05/2014 03:38AM by Mark a.
me2
Re: Sharpening and Knife Lifetime
June 05, 2014 04:03AM
We're at 30 or so now. I may finish up with a sharpmaker session and see what happens. It's surprising how much metal it can take off when creating/maintaining microbevels. After the 204 videos on the Scalper, it took a long time to rebevel the edge and completely restore the back bevel.
Re: Sharpening and Knife Lifetime
June 05, 2014 05:21AM
Just to clarify, how much metal is lost from the removal of the edge (cutting into the stone to reset it) vs forming the apex again?



Edited 1 time(s). Last edit at 06/05/2014 05:22AM by CliffStamp.
me2
Re: Sharpening and Knife Lifetime
June 05, 2014 06:48AM
Don't know. I will have to borrow the labs calipers for that.
me2
Re: Sharpening and Knife Lifetime
June 07, 2014 08:36PM
I switched again in an effort to speed things up, and minimize metal loss at the same time. I used the 220 grit Norton stone on the 17 dps block. This is getting a little silly. I literally spent more time soaking and switching sides than sharpening. With the coarser stone, and after resetting the edge from the hand sharpening, I was able to apex very quickly. Even 10 pps on the 220 Norton would apex and overshoot, forming a detectable burr. I started at 15 passes, then went to 20, back to 15, then 12, and finally 10. I also cut the destressing passes down to 2 from 4. In the end, the blade lost 0.008" of width, and is now down to 1.280" even.

Cliff, I tried measuring the loss after just one sharpening round and it's less than 0.001" for the 10 pps I settled on. I could not see any difference with my calipers (remember they're 0.01" graduations) after just 1 set of 10 pps, starting with the edge destressed, taking the initial measure, doing the 10 pps, and destressing again, and getting the final measure.

Careful experimentation would allow the absolute minimum of metal removal, keeping the blade width loss to 0.005" or less for 10 sharpenings. However, this assumes that just dulling is happening, and not damage/denting/chipping. I am not surprised any more that Cliff's Delica still looks like it's only been sharpened a hand full of times, as it seems possible to sharpen quickly, with extremely low metal removal if one takes the time to get the pattern down for an individual knife.

Any speculation on what would happen if I changed the edge angle to 12 dps instead? I think longer sharpening time, but the removal would be about the same in terms of blade width.
me2
Re: Sharpening and Knife Lifetime
June 15, 2014 08:28PM
So the knife is now up to 50 sharpenings, representing about 2.5 months of daily sharpening, or 1 year of weekly sharpening. I switched back to the King 1k stone, and after some trial and error, and slow going in the first 2 sharpenings, found that I could destress and apex, forming a small burr, in about 20-25 pps. So, The 220 is about twice as fast, at least, and the 1k stone is faster than I thought.

After 10 more sharpenings (50 total) the edge lost another 0.003" and is 1.277" wide at the heel, give or take a bit.

On a repeatability note, it might have been better to mark a place in the center of the blade. The heel can either be reduced faster or missed, depending on how consistent one is in the sharpening pass. From now on, I'll mark a center section and measure there in addition to the heel. It's also good to know that a little effort and some good angle control can really cut down on how fast the blade is reduced in width. The width change this time indicates less than 0.0005" per sharpening, and this is burr sharpening. I think it's still more than Cliff finds optimal, but still not too bad.
Re: Sharpening and Knife Lifetime
June 16, 2014 07:08AM
It would be interesting to see how much material is removed in the knife for sharpening after general use.
Re: Sharpening and Knife Lifetime
June 21, 2014 08:53AM
When I lived in the mountains (alps) in the north of Sweden a knifes life, for me, was about 5 years. After 5 years about 1 third if the blade was grinded and used away - and it was time for a new knife. Rhis was suring the sixties and seventies - and the sharpeners was sometimes aluminumoxide and sometimes natural stones.

My knifes (I used two knifes, one normal size and one chopper with 20 cm blade) was my only tools and I used them for everything. Their edges was as sharp I need ro have them ro be able ro trust them with my life, that means not to sharp, just as sharp they need ro be for that type of life. Sometimes I need to use a very sharp edge, and then I regreind the edge to that level of sharpness - and after the work was done, I grind the edge back to a lower levell of sharpness, this taka away more material then ordinary maintainence sharpening do,

So, the change of sharpness and the sharpener I used give my knifes a life time of 5 years - during that time.

Today I use diamond and ceramic sharpeners and when I am outdoors I have 3 knifes, my two old knifes and a very sharp small folder - and I do not regrind my knife any more - and the life of my knifes has increase a lot.

During 20 years I lived about 6 month every year in total wilderness and I sharpened my knifes by freehand. I could se what happens to my edges during this time. My flat edges become convex, and my convex edges become more and more convex for every sharpening I did. I learned to minimqze this - but this was the reason for me to start thinking about how I shall construct a sharpening tool I can use that not change my edge angles, both for flat and convex edges.

Thomas
Re: Sharpening and Knife Lifetime
June 21, 2014 09:06AM
Thomas, was the convexity intentional a result of faceting form angle variance? If you're willing to share, I'd love to hear more about your outdoor adventures, how it is you came to live such a lifestyle and the lessons you learned. I am sure I am not alone in that regard.
Re: Sharpening and Knife Lifetime
June 21, 2014 12:21PM
Chad234, my answer is that during freehand sharpening it is impossible to come below 3 degrees wobble. This means that all flat edges will be convex if they only be sharpened by free hand, that is my experiance after about 40 years of free hand sharpening.

The problem when this is discussed is that to understand this, you must use knifes a lot - and sharpen them a lot. Most people think that they use knifes alot.... Also them that use knifes 30 seconds a day....compare to butchers that use knifes 8 hours a day... smiling smiley

I normally say that this problem is not a problem for most people, but, for them that use knifes "a lot" this is a big problem. Some people never even se this problem becouse they use knifes very little - but still rhink that this is "a lot".

Next problem is that today in the kndustrial world, most people lives in citys- and they do not use knifes in the traditional way - they use knifes in materials that exists in citys. The problem, as I se it, is that city people, that is 90 % of the population! is also about 90 % of all forums members - and sharpening today is mostly discussed in teens of how sharp it is possible to get an edge - in the same time traditional knife users knows that an edge can have two big problems, it can be ro dull - or to sharp. They understand that an edge must be balanced innahatpening between sharpness and retention, that gives a perfect working edge. They also understand that if I take a good hunting knife and make that knife so sharp that I can shave with it - i have make a razor of the hunting knife and lost a good hunting knife.... No hunters use scarry sharp edges kn their knifes.

Kontroversel opinion, I know smiling smiley

I was married in to the Sami people and my wifes family worked with reindeers, hunting and fishing in the Swedish alps and I lived with them for about 6 month every year. It ended around 1980. 1988 I Seattle down out in the woods in the middle part of Sweden. My house stands where the road ends and I have Forest around me for many miles - and all the wild animals that is normal for this part of Sweden, moose, deeras, elks, bears, lynx, wolfs, beavers, and so on. I have lived, and still lives, in the nature most of my life.

If you have any questions about my years with the Sami people, just ask, I shall try to give you informative answers.

Thomas
Re: Sharpening and Knife Lifetime
June 21, 2014 12:33PM
I carry a hunting knife that is scary sharp. I can shave with it easily and often do. Yes sometimes I cut the hide when I don't mean to but I don't keep the hides anyways.
Consider this, when my knife is as dull as your working edge I have already gutted the moose and started skinning it. You will have had to put a new working edge on by that point.
The sharper it starts out the longer you will have a functionally sharp edge.

www.theflatearthsociety.org

BIGFOOT FINDS YOU, YOU DON'T FIND BIGFOOT!



IT IS THE E-NEP THROWING BROTHERHOOD
Re: Sharpening and Knife Lifetime
June 21, 2014 12:57PM
We keep our huds and like them without holes - and we prefer that the natural hins protect the meat from bugs becouse we hunt far away from roads and we sometimes must carry our meat for days to come home with it. I think that is the differance between our experiances.

Thomas
Re: Sharpening and Knife Lifetime
June 21, 2014 04:46PM
Quote
edgepal

... if I take a good hunting knife and make that knife so sharp that I can shave with it - i have make a razor of the hunting knife and lost a good hunting knife.... No hunters use scarry sharp edges kn their knifes.

In general, it isn't useful to try to make an argument by referencing popular opinion as that isn't reasonable justification, even if all the hunters you know use a certain type of edge on their knives that does not imply that type of edge is optimal or even that it is useful.

Havalon makes hunting (and fishing) knives and they ship them with actual surgical scalpel blades, they are a maker of surgical scalpels and they transitioned into making a hunting knife with the same blades because of requests from hunters who used to use the scalpels in that field. This however doesn't mean that the edge on a surgical scalpel is ideal for hunting because there is no information given as to what other edges those people used, how they use them or even why they prefer that edge or blade.

It also is necessary to actually say what is meant because terms like "I can shave with it" mean very different things to different people.

--

All of this aside I would be curious to know exactly how you sharpen a hunting knife intentionally so it can't shave, unless of course you simply mean shave as in it performs identical to a straight razor, not simply that it can take hairs off your arm.

For example, the maker behind Entrek was quoted as saying similar, that he didn't ship his knives shaving sharp. However if you get more detail what he meant was that they are not sharpened as a straight razor which is a very high polish. He gives them a very light buff/power strop, but doesn't full polish the edge so it still has some coarseness left from the belts. For many types of cutting, especially with coarse/carbide steels, that can lead to a higher level of cutting ability and edge retention.
Re: Sharpening and Knife Lifetime
June 23, 2014 07:38AM
No. Cliff, it is not a "popular" opinion, it is knife design tradition. During the history of man knife has been designed out of need - and then from use. The climate, type of wood, type of games, fish and other things designs the knife, the material, blade shape and edge.

In a smaller scale, shoemakers use shoemaker knifes, surgents use scalpels, knifes designed from needs - and from use. This has going on for thousends of years.

Cutting cardboard has nothing to do with outddor living - and material that is common in citys is not common in the wilderness, that meqns that whennit comes new materials and thise materials is regular used - there will also be a need for new knife designs - and then the use of this new knife decides the design.

The fact that knifes still develops when a new need upp up is perfectly normal - and as I see it a good thing.

Problems starts ro come when city people, without experiances from outdoor living, starts to design knifes dor outdoor living. For me, that is fantasy knifes.

What is a ultimate hunting knife for you - and for me? For people in Afrika, the Sami people in north Scandinavia above the arctic circle - and for the Inuits? The ultimate hunting knife design decides by the climate, what game that is hunted, how much you can carry/transport and some other things. It decides also if the hunt is going on suring the summer or the winter - and above all this, who is the hunter and what traditions is he living in.

Inuits skin a lot with an Ulu, we do not. In north Africa they used a strongly curved blade, and so on. We use skinning knifes - in different design depending on where we live on Earth.

Yes, to shave hair sot tell anything, I agree. We have all different type of hair, some have "angel hair, some have steelrods as hair. Hair differs a lot in thickness and quality.

95% sharp for me is that I can shave hair from my arm but the hair dont pop - and I have thin hair (angel hair). I cannot compare my arm hair to others arm hair becouse I do not shave other peoples arms smiling smiley I very seldome shave my own arm - but it happens that I test sharpness that way.

For some years ago I was on a knife fair and a man in front of me grab my arm and start to show how sharp his knife was by shaving hair from my arm... I think he never do that again, ever. (I look at his arms, he has not any hair at all on them).

Thomas
Re: Sharpening and Knife Lifetime
June 23, 2014 08:14AM
Quote
edgepal

No. Cliff, it is not a "popular" opinion, it is knife design tradition.

Thomas when you make an argument and you use as justification that it is done that way or that a number of people claim it is that way it is called making an argument from popularity, it is a logical fallacy because simply because someone does something, or even if a lot of people do something or believe something does not justify a claim as to the nature of that action/belief aside from the fact that it is popular.

It should be obvious that this is not sensible justification with even a little thought.

For example at one time everyone on earth thought the earth was flat. Eratosthenes of Cyrene is the person generally first credited for realizing that the earth was actually curved not flat and he did it through an experiment and that experiment then caused the rejection of all of the opinion of everyone else. It didn't matter that it was one person vs everyone else, it didn't matter that people thought that way for thousands of years, it didn't match experiment and so it was rejected.

You can continue on with the fact that at one time we readily accepted slavery, we treated different races as not even being human, we saw women as being not having the same fundamental rights as men and even thought they were incapable of higher learning, children could be sold as chattel, etc. . These things are no longer accepted and the fact that they were done for hundreds (even thousands) of years doesn't matter and isn't rational justification for them being true.

Now it might seem harsh, but that is the reality. It doesn't matter what people use where you live in terms of that being justification as a claim that design is optimal or even useful because that is just a claim from popularity. It is only rational justification if the reasons why they use it are proper justification, the use itself is not indication of anything beyond the obvious.

As I have noted, it is trivial to make the exact same argument from popularity with a completely opposite criteria using the Havalon series of blades which use surgical sharp razor blades for hunting knives. This however is just as flawed and it not reasonable justification that surgical scalpels are the best hunting blades because again it is just an argument from popularity.

--

If we want to have actual meaningful discussions then we need both details and justification, so if you say something like :

"... make that knife so sharp that I can shave with it - i have make a razor of the hunting knife and lost a good hunting knife."

Then it needs to know :

-what do you mean when you say you can shave with it

-how do you sharpen a knife as a hunting knife and deliberately not be able to shave with it

-how do you sharpen a knife so you can shave with it

-what happens when you use both knives as hunting knives

--

I realize you have experience, but so do lots of people here, making arguments with the justification "I am experienced so ..." is the kind of thing that happens on other forums and goes no where, it is the fallacy of argument from authority.

You reference how the innu skin, I am actually part first nations (labrador), the ulu is used by women, it actually translates to "womans knife", and it has the shape it has for many reasons aside from skinning because it was used for many things including sewing and cutting hair.

This is why arguments from popularity/authority don't work because it doesn't matter how many people hold an opinion, it only matters why. In many cases things are the way they are simply because it was tradition.

It is like this old joke :

A boy goes to the store to pick up a ham, when he returns home his mother is upset as he didn't get the end cut off the ham. He asks why? She says you have to, it won't cook right otherwise. He asks why? She gets upset and says my mother always did it that way to get it to cook right, go ask her!

The boy goes and asks his grandmother, she repeats almost the same thing word for word. Being ever so curious he goes to his great grandmother and asks he "Nan, why do you have to cut off the end of a ham for it to cook?" She replies, "You don't, who told you that nonsense!". The boy tells her and the grandmother laughs and replies "Johnny, I cut off the end when I bought hams because that was your great grandfathers favorite part and I always cooked it the next day just for him for lunch."

--

Silly yes, but even a hundred years of tradition doesn't justify anything aside from the fact that it is tradition because without knowing why something was done and what was used to make that decision then there is no grounds for justification.

As another argument from popularity which is meaningless.

I live in a farming/fishing community, the knives which are traditionally used to fillet fish look like carving knives. On an entire island of fisherman you see the same design over and over among people who fish to live and survive. Does this mean that is an optimal design? No. The reason they used that knife is because it is what was left over after you use a chef's knife for a very long time and the blade gets very slim. It is no longer useful as a chefs knife so it ends up being the one used for fishing work. It has many issues with use in fish work but it is basically free and those people could not afford to buy knives just for fishing so they used what was on hand. Most of the local knives are literally generations old and often they date back to the first settlers. The simply could not throw out knives and so used them for until they were gone.

In the same way the filleting knives eventually were worn down and became rough splitting/heading knives, then they were used for cutting out tongues then they would be used for shop/yard/craft tools. In none of these cases was the design used for any other reason than it was basically free and had to be used for something because it was not going to be thrown out.



Edited 2 time(s). Last edit at 06/23/2014 08:21AM by CliffStamp.
Re: Sharpening and Knife Lifetime
June 23, 2014 09:05AM
Thomas,
I lived in the city most of my life. I had never hunted until I moved to the woods in my thirties. Funny thing is that I can cite anecdotal evidence to support my position as well.
The first year I hunted was with a family that had hunted all their lives. Between them they share hundreds of years of hunting and outdoor experience. When I took my scary sharp knife and slit the moose from tip to tail in one long slice they were all amazed. In fact each one separately asked me to sharpen their knives for the next season.
The reason for this was simply that they did not know how to make their knives as sharp as I did. Not because they preferred a duller knife. I showed them how I did it and now all of them use a sharper knife.
As cliff said just because it is the way it has always been done does not always mean it was the right way.

www.theflatearthsociety.org

BIGFOOT FINDS YOU, YOU DON'T FIND BIGFOOT!



IT IS THE E-NEP THROWING BROTHERHOOD
Re: Sharpening and Knife Lifetime
June 23, 2014 09:23AM
To clarify and expand a little on what Mark wrote, I am not saying that user preferences and feedback have no value, but just like every other observation you need proper methodology in order to infer justified conclusions.

For example I sharpen knives for people on a regular basis, just regular people, housewives, fishermen, hunters, tradespeople, etc. . I make small changes from time to time and don't tell them and then ask them for feedback, this is done to reduce bias.
me2
Re: Sharpening and Knife Lifetime
July 02, 2014 08:30PM
I think I'm done with my part of this experiment. I satisfied my curiosity regarding how much metal is removed during sharpening. With care and practice (both very important), I can sharpen the knife in question, including destressing the edge, and remove as little as 0.0005" of width per sharpening. This is with forming a detectable, but small, burr. That translates to 0.05" lost over 300 sharpenings. If sharpened daily, it depends on how tolerant one is of blade width loss. If sharpened monthly, that is 25 years.

Keep in mind a few things. I'm using an angle guide that I am very familiar with for this particular knife. I was checking frequently early on to see how few passes it would take to apex the edge and in most cases form a detectable burr. On the 220 grit stone it was as few as about 8 pps. On the 1000 grit, it was about 15-25. After I got the number of passes zeroed in, resharpening became much faster, as I could skip all the checking the edge steps. Just put it on the stone and apply 20 passes per side, and done. Apex formed, small burr along most of the edge. Also, I did not actually sharpen the edge, just get it to the point that 5-10 pps on the Sharpmaker would finish it off.

I have other plans for this knife that will require rebeveling ultimately to 7 dps, so I don't want to keep going with the 17/20 dps sharpenings. As for the other parts of the discussion, carry on.
Re: Sharpening and Knife Lifetime
July 03, 2014 06:03AM
Quote
me2
With care and practice (both very important), I can sharpen the knife in question, including destressing the edge, and remove as little as 0.0005" of width per sharpening.

It might be interesting to pick a knife you don't like, sharpen it to a burr you can feel at each stage and then minimize it at the end, as how sharpening is often done and see how much of a difference that makes. Now this is obviously influence by how many grits you use, but it would be curious to see how bad you could make this with say 4 grits all burr sharpened.
me2
Re: Sharpening and Knife Lifetime
July 03, 2014 09:06AM
Crud. My math is off. 300 sharpenings is 0.15 inches at 0.0005"/sharpening. The 0.05 mark is 100 sharpenings.
me2
Re: Sharpening and Knife Lifetime
August 30, 2014 07:57PM
Ok, after a long time of working at it, I rebeveled the RADA knife to 12 dps on the Norton 220 and King 1000 stone. This seemed to take a long time, but who knows really. I worked on it a little every night for about 5 days. I don't expect to see a difference in the amount of metal removed, but I wanted to see how many extra passes it took to reset the edge.

After raising a small burr on the 1k stone, I cut into the stone lightly and had a visible flat all along the edge. I then reset the edge with just the 1k stone. I expected it to take much longer than it did. I was still able to apex the edge in about 25 passes per side on the 1k stone. I need to do it again to be sure it wasn't a fluke. My main interest was to see if the lower edge angle and increased bevel width significantly increased the shaping time. So far it looks like it doesn't increase it noticeably, though about double the bevel width is involved.
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