Hand sharpening vs. Using a system

I wrote above: the differance between 10 and 11 degrees are 1/1000 part of 1 mm in thickness of the cutting edge. That is 1 my differance.

If I use a 25 micron sharpener - what is needed to remove 1 micron material from the cutting edge?

To understand how sharpening work - we must go down to this = 1 my = 1 degree on the cutting edge. When we understand this tiny thing - we can start to discuss how wobble Ada up with the number of wobble, how big the wobble are - and how many sharpenings it takes to change an edge.

Yes HavyHanded we have had this discussion before I have discuss this many times during the years.
I like that you agree about the Basics. Then we can start to discuss the 1 micron more, or less, material in the xutting edge that means 1 degree change if 1 side of the edge.

Chris A,
No you are more wrong then correct. My tool Chef have a fixed distance between the cutting edge and the pivot point = Chef can be adjusted for different blade width - and the protractor shows the correct degrees for all blade widths.

The distance 28 cm makes that 25 millimeter change between the cutting edge and the pivot point is 1 degree change if the edge = if the distance change to 25,5 cm (from 28 cm) the edge will be 1 degree steeper. Your principle are correct - but Chef allways use 28 cm distance and the blade width do not matter, you will get the wanted degrees with Chef. Chef was the first sharpening tool that are asjustble for different blade width - and that was the solution for the built in peotractor that Chef also was the first sharpening tool to have. If I remember correctly, Chef was first with 16 functions, this was two of them, convex edge sharpening was a third, and so on...

Removing burr. When a sharpening tool is exact and give 100% flat edges - the burr also gets an exact thickness - the same thickness all along the edge. This means that the burr are easyer to remove.
When you sharpen by freehand, you wobble = the xutting edge will NOT be straight, the cuttingedgecutting WILL get thinner, and thicker, parts - and the burr also. This makes the burr harder to remove - and when you have renove the burr, it WILL give flat oarts on the cutting edge - ABS thise fkat parts have sifferent widths. This is possible to se with reflexion light, it looks like dots, not as a line. When you take this flat surface away, you must sharpen the edge two surfaces compleatly together again. (Sorry I lack words here and I cannot describe this correctly).

Once again, we are now discussing the messuring My and less,= less then 1/1000 parts off 1 millimeter things, things we cannot meassure our selfs.. But ut starts there - and adds up.

Yes, it is important to understand freehand sharpening - and different sharpening tools and what they can perform. Here is a big lack of knowledge - and most people think that all tools workshop same - when it is a very big differance between how the tools work and what they can perform.

There is one thing that works the same - if the knife are locked in its position on the grinding table and cannot move - and if the sharpening angle are locked to the wante degrees - it cannot be anything else then 100% flat edge. That follow the law of fysics. Do not argu about that :)

Tools that so not lock the knife on the grinding table or not lock the sharpening angle will not give 100% flat edges. This is facts.

Then, all people do not need 100% Fiat edges - but that is another discussion. ;)

So, we have come a long way now, you guys accept that there is wobble innfreehand sharpening - and no wobble in a sharpening tool (if the tool are correct made and stabile). I like that. Now can we go forward and understand the consequences of this - and go down to my, the deigned water that destroyed stone - and that the first drip starts this process.

I like that we discuss as friends and that we are polite. I enjoy this discussion.ä

Thomas
 
E EdgePal

Well, I was referring more to popular clamped sharpening tool and not your Chef :)

Same as your Chef if set to do convex, if the freehander aim for 15° by shooting at 12° (at error of 3° that you mentioned), the final apex will be 15° or less. Cannot be more and it will not grow to be 20° if the same process is repeated. Granted, the edge will be convex and not flat but final apex angle will not add up. There might be more steel removed than necessary (behind the apex, when the angle is between 12°-15°) but the freehander will achieved final apex he wants. This is what I meant by compensating the wobble. Just go lower.

I’m not saying there is no need to have perfect flat apex bevel (15°) from edge to shoulder. I’m saying in my use, having thinner shoulder is ok, it doesn’t hinder the cutting, probably a bit weaker but I don’t usually twist during cutting.

I’m interested to know in what application you use that it requires really flat apex bevel angle, if you don’t mind sharing.

I have seen @HeavyHanded jig also.
These devices will get as accurate as the measuring tool is (and the flex in component using to build them). Angle meter, micrometer, etc. all have approximation. We just need to adapt their limitations to achieve the level of maximum allowable tolerance.
 
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I suck at free-hand and use Edge Pro.
It is not quicker than free-hand, as you have to set the system up each time (I don't have a designated area for it).
Also, it does not have a clamp, such that a single stroke at a wrong blade position can set your work few stones back.

The benefit for me to use it is that it gives me a very nice flat edge bevel at a known edge angle, which I can replicate easily.

Umnum_edge1.JPG
 
I recall a discussion like this, a few years back. *It ended up in some complex geometry and disagreement.
Lets see where this goes, one thing is clear, sharp knives are what we want.

Russ
 
miso2 said:
Also, it does not have a clamp, such that a single stroke at a wrong blade position can set your work few stones back.

The benefit for me to use it is that it gives me a very nice flat edge bevel at a known edge angle, which I can replicate easily.

Umnum_edge1.JPG
Click to expand...

I also have an Edge Pro, (Apex), and am just now getting back to using it after a long hiatus. But I wonder if what you say is not a contradiction of sorts.

Since the blade is not clamped, the slightest change of position when flipping sides, where the edge is aligned in relation to the forward end of the machine, or similar changes during future sharpening sessions would seem to me to argue against the ability to easily replicate (in terms of exact precision as opposed to "good enough").

Not being argumentative, as I definitely want to enhance my skills on the machine for those times I use it...but I wonder how precise the replication may be.

Interesting discussion.
 
Chris A,
If/when, you understand the problem, then can you try to minimice the problem. But you cannot take away this problem, only minimice it. Thats means tyat you dont se the problem after 10 sharpenings, you se it after 20 sharpenings instead. The problem is still there - but it take longer time before it shows up.

With for example Chef and the "convexing" guide rod - the peoblem is not there at all becouse you adjust to what degree you like to have on the cutting edge and then hiw many degrees you like ro have on the backbevel - and what you have asjust the edge to be - this is the edge you get - and you can maintain this edge in the same angles as many time you like. That is my solution of this problem.

When you use freehand you wobble. If you are skilled in freehand sharpening you can come sown to 3 degree wobble, you cannot come below that becouse 34 joints inside your body are involved in the sharpening (how many moving joints have you ever seen on a industrial robot - and why is the moving joints as few as they are on a industrial robot )?

Freehand sharpening wobble, you cannot come below 3 degree wobble, if you are skilled you CAN come down to 3 degrees - but most freehanders wobble more then 3 degrees. This is imortant to understand bexouse it is the Key to make better edges.

I understand that it can be hard to accept - but use the laser tool - and you will se that it is true.

Also understand that most people dont even se this problem becouse they do not use/sharpen their knife so often that they 1, se the peoblem and 2, understand the problem. For them, this problem so not exist...(but they all use knifes a lot) ;)

In the same way of arguing, when I discuss hiw knifes warns and that knife blades are grinded away - the answer almost allways is that they use many different knifes so that is why the warn cannot be seen... (They do not understand that also very tiny warn can be seen).

Myths ans ignorance is a big problem in the knife world - and the reason why it do not change or develop - in my mind.

I can only talk about my tools, not about other tools. I am the only one that makes tools by hand and that have rhis toolmakers as a hobby, i dont se other toolmakers as competitors becouse i just nake a few tools per year - and they make hundreds and some makes thousends of tools per year.

Perfect flat edges slice better and slice with less force. That is what we discuss - and how changes of ghe edge starts and hiw eveeything ads up - ans how it will "destroy" the edge function.

For people that whittle 8 houers per day, this understanding are extreamly important to understand, dor people that whittle a barberque stick 2 times per year, this is nit a peoblem at all, they have no need for understand this problem - ans they never even se the problem (but if you ask them - they use knifes a lot) ;)

All freehanders talk about how limmited sharpening tools are :) and innthe same rime they admit that they wobble,mannattbhitt a constant angle and so on - and all rhose things can a sharpening tool do. When ut comes ro quality sharpening and precision - freehanders come not even close to what even simple sharpening tools can perform.

Miso2 shows a picture on a edge he have sharpen om a EdgePro. This is a very good edge - and it is made with a tool where the knife are hold in position with the hands,mthe knife is NOT locked in its position in the tool. Look at the edge and look at the Back edge - and you se a very nice straight line. Miso2 are skilled to use a EdgePro. He holds the knife veey stabile on the grinding table and he so not move the knife during the sharpening process what I can se from this photo.

Very good work Miso2! Respect!

Thomas
 
Mycough,
There have been discussions like this during long time. Most of them have ended in anger, mostly becouse some people so not see, or understand, this peoblem, this becouse they have never seen it or if they have seen it, they have dont understand it.

it was impossible to diacuss this for 15 years ago - but there are more knowledge today i think. If the discussion starts to be angry And derail, I just leave the discussion. I am here becose i like ro discuss - i am not here to argue hard for things well known and that follows the law of fysics ;)

as we have seen in this thread, the use if sharpening tools and guids go at least 6000 years back in time - and most people thinks that sharpwning tools is a new thing made for people that cannot sharpen by freehand. It is far from that, sharpening tools have been used for at least 6000 years by people that like to have quality edges and easy maintainence of them in correct angles.

We still se argument about that sharpening tools are limmited - allways from freehanders - and freehanders are really limmited becouse of the wobble that they cannot avoid what ever they do by freehand.
Tools can also be limmited, most tools are. But they have one thing in common - they do not wobble if both the knife and the angle are fixed. That is the base for there existence. That makes that people can choose between wobble - and no wobble - and their needs decide what they choose.

Freehand sharpening wobble - but are useful becouse no tool are needed - but a tool makes better edges. Then, again, most people do not need perfect edges or perfect flat edges or true convex edges - but that is another discussion. Who needs what :)

Argument that it takes years to learn and that it needs years of daily practice is BS for me, there will be wobble anyway - what ever people do or how many years they have practice - and I think that we all shall notice is that anyone can clime anything on internet...it is safe, no one can check...

Lets do this clime unsafe to make, let us demand a laser tool video when they show the quality they clime - and those climes will dissapeare - and the rest of us can discuss facts - not myths. That will be good for all of us.

Thomas
 
Being a tool and die maker I am kinda anal about precision so I only sharpen with guided sharpeners. No way could I even get close to holding as consistent an angle by hand that I can with my Apex, which I think is critical as you progress through your finer stones. If you maintain consistent angles then the amount of time you spend with the finer grits will be much less, with my current diamond stones I use as few as 10 strokes with each stone to clean up the scratches from the previous one. I am also becoming a big believer in apex trailing strokes for my stones above 17 micron.

The trick with using an Edge Pro is to position the knife with the hand holding it, somewhat loosely, and to hold it flat against the blade table with the stone. A 1/4" x 1/2" x 1-1/2" neodymium magnet under the Apex blade table helps too.
 
Diemaker,

I am not anal with it - but some people say that I am a asshole becouse of it :)

One "problem" with sharpening tools is that they are exact - and that a minimal change of the angle will show clearly - also 1/1000 part of 1 degree will show - and then people think that tols are not exact :) in the same time 3 degree wobble can nit been seendet all - and people belive that they are skilled.

One man use one of my tools on a fair use very high pressure and that changed the angle just a little depending on that tha guide rod flexed - and he become extreamly happy and pointed on differance in angles - and of cause - he could hold a better angle by freehand. It did not help that I explained to him that the less the angle change it is easyer to se it.

Have you ever sharpen a knife for the first time and this knife have the same sharpening angle on both side if the edge?
I have use tools for 20 years and sharpen tenthousends of knifes - and I have never seen it - and this is probebly nearly total unknown by people that not use tools.

Thomas
 
Diemaker said:
A 1/4" x 1/2" x 1-1/2" neodymium magnet under the Apex blade table helps too.
Click to expand...

Diemaker, I've never tried using a magnet with my Apex though I've seen them offered for use with the Edge Pro.

Question: Doesn't the magnet create issues with swarf being attracted and held to both the table and blade?
Even if I could live with a magnetized blade, I wonder if that would be problematic.

Be interested in your take, as well as anyone else's in this regard.

Thanks.
 
Blues, the magnet doesn't attract too much swarf while sharpening a few knives, but I like to keep things clean while sharpening. The magnet is a new adition but so are the diamond stones I am using. I wipe the knife off after each grit so everything stays clean, one benefit of these diamond stones is there is no stone grit in the swarf. As far as magnetizing the knives it is pretty minor and sharpening will magnetize the apex a little anyway. In normal use my knives are not around any metal filings so a little manetizm would not be noticed. To be honest though it does magnetize them a little.

The magnet I use is N45 with 26 lbs of pull, the most I found I could stick in the space allowed.

Using a magnet left me wanting a different guide plate. The anodizer should be done with the one I made today, mmm hard anodized!
 
Diemaker said:
Blues, the magnet doesn't attract too much swarf while sharpening a few knives, but I like to keep things clean while sharpening. The magnet is a new adition but so are the diamond stones I am using. I wipe the knife off after each grit so everything stays clean, one benefit of these diamond stones is there is no stone grit in the swarf. As far as magnetizing the knives it is pretty minor and sharpening will magnetize the apex a little anyway. In normal use my knives are not around any metal filings so a little manetizm would not be noticed. To be honest though it does magnetize them a little.

The magnet I use is N45 with 26 lbs of pull, the most I found I could stick in the space allowed.
Click to expand...

Thanks, Diemaker. (I'm a bit of a clean freak myself while sharpening.)

I've had Ben's two versions of his diamond hones for the Apex for several years though I've only used them a handful of times. (Without magnets, obviously.) I liked them for convenience before finishing on finer diamonds and ceramic.

I've got pretty much the entire array of DMT diamond hones but only those two from Ben set up for the Edge Pro, which as I mentioned has been sitting unused for a while until recently...while I sharpened either freehand, on my Sharpmaker (enhanced by diamond, ultra-fine and Congress Tools rods), or with DMT Diafolds aided by a magna-guide and old Gatco clamp (similar to a Lansky).

I still find freehand the most satisfying (and frustrating) but intend to make a commitment to mastering the Edge Pro.
 
I use magnets on Chefs both grinding tables, tye small grinding table have Two Neodyme magnets with 7 kilo power each - and a third can be attached. The long grinding table use 4 magnets.

The magnets collect the metal dust (swarf?) and keep the edge cleaner from dust then without magnets.

Some blades can be a little magnetized - but most do not. It depends also how you you lay down, and take away the blade from the magnets. If you slide the blade against the magnets the blade will be a little magnetized by this sliding. If you lay down, and take away, the blade like laying it down on the magnets from standing on its neck = a kvarter of a full turn of your wrist, the blade will not be magnetized.

In kitchens it is popular to have magnets holding the knifes - and if you do not slide the blade against the magnets they will not be magnetized.

I have not find any peoblem what ao ever with a blade that is magnetized. IF you like to take the magnetic power away it is simple to do.

If you like to magnetice a screwdriver so it can hold screws, just slide a magnet along the screwdriver in one direction - and it will be magnetic. When take away the magnetic power from the screwdriver hold it innthe handle and hit its tip agains a anvil, vize or something "big" - and the magnetic power dissapear, it so not need to be a hard hit, just a fast hit. Do the same with a magnetic blade.

Thomas
 
Blues, the resin bond diamond stones I am referring to are the 2300 and 4000 mesh polishing stones they started selling around 2 years ago. I make them and have made a few with different meshes to play with.
 
Diemaker said:
Blues, the resin bond diamond stones I am referring to are the 2300 and 4000 mesh polishing stones they started selling around 2 years ago. I make them and have made a few with different meshes to play with.
Click to expand...

Cool. I just bought the 2300 from Cody last week. Haven't yet had the opportunity to employ it. It'll be my maiden voyage into polishing. (I'm a lazy so and so who usually pronounces "good enough" way before those with more drive.)

I'll have to work on getting my Edge Pro muscles tuned up again before I venture down that road, but I will.
 
I am finding they work best using NO extra pressure on the rod, just the weight of the stone and holder rod assembly using an edge trailing stroke with a little water. The diamond is very sharp and doesn't need much pressure. The grit progression is designed to work with 10 strokes on each side of a 3"-5" blade, I usually use 15-20 strokes when sharpening knives just to be sure when I don't have my microscope out. If it takes more than this then something is off. The stone expected to be used before the 2300 is their 1000 Alox. To clean them when they turn dark use a cloth or paper towel soaked in rubbing alcohol, it works really well. If after sharpening a few knives it is leaving more scratches then dress it using some 320 ish Sic wet sand paper. I recently figured out the best way to dress them is with a 350 mesh abrasive using their stone leveling kit, it just does the job a little better.
 
Thanks for the tips.

I have a new 1000 that I bought from Ben a few years back.

I also have the leveling kit but only the silicon carbide abrasive they sell by the bag, which I think Cody said is too coarse. (I also have the fine, x-fine and x-x-fine DMT hones in case any of those would work, as well as wet dry paper.)
 
Definitly do not use your diamond stones as leveling stones, the resin stones may dull your plated ones. If you dressed your 1000 mesh stone first with the leveling kit then the Sic would be ground up enough to dress the resin stone. The coarser grit will dress the resin stone fine, it just will remove a little more stone than a finer grit abrasive. Dressing these stones is where all of the wear occurs, not from sharpening knives. If you take good care of it, it will last a lifetime. Cody has been trying to get some finer abrasive but can't find anyone in the north west here that stocks it. He should have it fairly soon.
 
Blues said:
I also have an Edge Pro, (Apex), and am just now getting back to using it after a long hiatus. But I wonder if what you say is not a contradiction of sorts.

Since the blade is not clamped, the slightest change of position when flipping sides, where the edge is aligned in relation to the forward end of the machine, or similar changes during future sharpening sessions would seem to me to argue against the ability to easily replicate (in terms of exact precision as opposed to "good enough").

Not being argumentative, as I definitely want to enhance my skills on the machine for those times I use it...but I wonder how precise the replication may be.

Interesting discussion.
Click to expand...


Yes. A slightest change of the blade position can degrade the quality of the edge.

You have to set the blade guide (slider) for each knife separately and position a knife in the same way each time.

What I struggle most at the beginning was how to lay down the blade and keep the same angle on the stage.
This is easy for full-flat grind knives but not so for others.

Now, I can hold a knife very consistently but still have to be careful about the position of the tip.
 
EdgePal said:
Miso2 shows a picture on a edge he have sharpen om a EdgePro. This is a very good edge - and it is made with a tool where the knife are hold in position with the hands,mthe knife is NOT locked in its position in the tool. Look at the edge and look at the Back edge - and you se a very nice straight line. Miso2 are skilled to use a EdgePro. He holds the knife veey stabile on the grinding table and he so not move the knife during the sharpening process what I can se from this photo.

Very good work Miso2! Respect!

Thomas
Click to expand...


Thank you for the compliment.
One trick is that I use just a single coarse stone (#240 or #320) for sharpening and therefore do not have to worry about angle variations due to stone thickness.
If I polish an edge with multiple stones from coarse to super-fine, the edge may not be that consistent.
 
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