more toothy thoughts

[Ken S]

Rupert, 

Once in a great while I read a post I consider inspiring. Your last post was inspiring.

Thanks for sharing.

Ken

[grepper]

Mr. Rupert, Sure!  I'll give 120 grit a try.  Nothing like a wonderful toothy edge.

Scotch Brite to refine the edge???  I have not had good luck doing that and have found that Scotch Brite belts dull the edge.  Even the extra fine ones.  I tried it.  I tested the sharpness with the PT50B.  It did not pan out.  Am I doing something wrong?

Oh, a knife in a minute?  Most excellent.  Very cool.

[Ken S]

Grepper,

Do you want your edges to look pretty or just cut well?  

Ken

[Rupert Lucius]

Mr. Rupert, Sure!  I'll give 120 grit a try.  Nothing like a wonderful toothy edge.

Scotch Brite to refine the edge???  I have not had good luck doing that and have found that Scotch Brite belts dull the edge.  Even the extra fine ones.  I tried it.  I tested the sharpness with the PT50B.  It did not pan out.  Am I doing something wrong?

Oh, a knife in a minute?  Most excellent.  Very cool.

A few years back Don was doing a baseball teams knives in New Mexico - we started on our tele conversation,  less than one hour later Don had done 50 knives in less than an hour.

This week Don did the same thing for a restaurant chain (independent franchise) in NW Arkansas.

The buff is magic - it brings the BESS number down about 40 points.  You can feel, hear, and see the difference in the edge when tested on adding machine PAPER rolls - edge is so smooth - with a very toothy edge remaining..  NCR paper is maybe a bit more consistent from year to year than the house brands.  Excellent test media excellent.

Forget that scotch brite belt and use instead a 3M EXL 8 inch wheel to blend with.  You could also use a paper wheel with compound to blend with.  Often I use a homemade MDF wheel  8 inch dia 1 inch thick with nothing on it.

Go direct from the 120 belt to the buff?

We mind F sharpening tooo much.  What did our grand parents use?  my  Grandmother used a  sand stone wheel.

My wife EVER grew up in Mexico used a piece of saw blade with friction tape, brick, cement block or what ever (maybe a rock from a creek).

Rupert

[grepper]

I agree with you on one point Mr. Rupert; we have made sharpening way to difficult and complicated. Unless you are going for some super polished edge, sharpening is super simple and very quick.

Burr removal is more difficult, and in my mind, just as if not more important than the actual sharpening.

Of course, I could be laboring under a delusion, but I have not seen that a buffing wheel can completely remove burr.  I've tested it a number of times with both sharpness testing and microscopy. It did not pan out.  There was always burr remaining.

Concerning Scotch Brite duburring:  As I mentioned before I've found it to dull an edge so I want to make sure I'm understanding you correctly.  Are you saying that you use the Scotch Brite wheel to deburr the edge right after sharpening?

What do you mean by "use instead a 3M EXL 8 inch wheel to blend with" ?  What do you mean by "blending"?

Sorry for being a bit slow!

[Rupert Lucius]

I agree with you on one point Mr. Rupert; we have made sharpening way to difficult and complicated. Unless you are going for some super polished edge, sharpening is super simple and very quick.

Burr removal is more difficult, and in my mind, just as if not more important than the actual sharpening.

Of course, I could be laboring under a delusion, but I have not seen that a buffing wheel can completely remove burr.  I've tested it a number of times with both sharpness testing and microscopy. It did not pan out.  There was always burr remaining.

Concerning Scotch Brite duburring:  As I mentioned before I've found it to dull an edge so I want to make sure I'm understanding you correctly.  Are you saying that you use the Scotch Brite wheel to deburr the edge right after sharpening?

What do you mean by "use instead a 3M EXL 8 inch wheel to blend with" ?  What do you mean by "blending"?

Sorry for being a bit slow!

Wish we agreed agreed on more points.

We both agree on burr removal importance.  Try the untreated loose buff it works for me (Woodcraft).  Use the buffed edge for cutting paper or etc and rebuff until you get the results desired.  DO NOT over buff do not over buff -  I am not talking about rounding the edge over.  When (sharpening) the "apex" is created - LIGHTEN up,  lighten up.  Once you have sharpened both bevels, and  they shake hands STOP sharpening and begin burr removal if any burr remains (very light touch one or two passes). 

In ref to the remaining burr if any is remaining often sharpeners chase said burrs with a progression of finer grits (I do not).  We need to be very careful and let the sharpened bevels shake hands before we start burr removal.  Again I  often use a Scotch Brite belt to de burr, anything will usually work a MDF wheel, EXL wheel, cross grain (end grain), a polished steel - anything will work.  Again the stated Woodcraft buffing wheel is my favorite.  WOW! what an edge.  If the two sharpened edges shake hands we will always end up  with very little de burring and a very sharp blade.

Yes! I use a Scotch Brite belt to de burr with (blending).  Use the  Scoth Brite WHEEL to remove rust, dried blood, guts and etc.

The EXL wheels are 3M products and an are entirely different product.

Blending for me is the transition between a properly sharpened edge and on to the final burr removal if any remains (cotton buff).

You are not slow I am not the writer that you and Ken are.

We need Thomas (EdgePal) to enter this conversation.

Rupert

[grepper]

Mr. Rupert,  Thanks for the additional explaniation.  Appreciated!

"The EXL wheels are 3M products and an are entirely different product."

Hmmm... OK.  I can intuitively imagine how a Scotch Brite like material would be good at deburring.  That's why I tried a Scotch Brite belt in the first place.  If those wheels are something different, I'll look into it.  My testing with Scotch Brite extra fine belts was not encouraging.

What I have found is that removing the first bit of burr is not that difficult.  It's that last bit if remaining burr that is wider at the base just above the edge is what is difficult to remove.  I was never able to remove that with a cotton buffing wheel.  Maybe the one you reference is significantly different from what I have.  That's always a possibility.

Also, please understand that when I say something didn't work for me, that does not mean it does not work!  I'm just sharing the results my own testing.  For things like deburring, I'll try something, check it under the microscope, test for sharpness and repeat, etc.  While I try to be careful enough to at least conduct a test that will result in informative results, it is by no means conclusive and/or definitive.  It's just what I've seen in some particular tests.

I have seen blades with remaining burr that test as very sharp.  What I think happens is that the burr itself has been sharpened and is very straight out from the edge.  Even though it can test as very sharp, shave hair and cut paper, etc., because I can actually see remaining burr I assume that edge won't hold up very long.  I have even seen times when after that burr is finally removed, the edge will test as slightly not as sharp.  But that is actually a good thing because what remains is the actual edge that will endure, and not just sharpened burr material.

A lot of you guys have sharpened far more blades for many more years than I have.  I would be perfectly happy to one day find out that everything I know is wrong!       I really appreciate any and all feedback and info.  I just want to learn, so I welcome and am thankful for any and all ideas and information!

[Edgepal]

Ö As I se it, knife design and edge types and edge angles, have split up to two developing path. The traditional developing path and the city people developing path. I think I wrote about this earlyer.

Traditionalists never use polished edges, they normally stop sharpening in around 25 micron and a few passes on a leather belt. Traditionals use their knifes in fresh wet wood and other soft materials, they skin and butcher - and their edges holds around 20 degrees total. My chopper have 26 degree edge total.

City people (90% of the population) use knifes in different modern materials, plastic, nylon, rubber, card board, dry hard wood and so on - and they need higher edge angles for this type of materials, it is normal with 40 degree edges total. Polished edges have become modern - but in my mind (I am a traditionalist) there are only Suchi chefs Chefs and sergeants that need polished edges...

Burr removal is necesarry for both developing path - but city people use loupe or microskopes to find the burr and use different methods to remove it. Traditionalist bend the burrdorwards and back and remove it with slicing in wet wood or similar, some like to slice a little in their rubber both
Traditionalists dont use loupe or microskopes.

25 micron edges are a little tothy and tothy edges work nice outdoors, are nice to skin with and work good in fresh meat - not so good in wood.

In my life I take care of my knifes and sharpen my edges perfect at home before I went outdoors for 6 month. My knifes have slightly convex edges (2,5-3 degrees convex sphere) and that make them easy ro maintain by freehand during 6 month. I prefer to maintain my edges daily, often with only a strop (my leather belt).

I like tothy edges on working knifes outdoors.

A knife shall only be as sharp it need to be for its purpouse it is why we, for example, have razors to shave with, thin edges that penetrates hair good - and ghe tothy edge get good grip in hair.

Most of you have filéa knifes for fish. Make an experiment. Make the edge very sharp och polish the edge - and then filéa a salomon. You will feel how the edge slice thru the ribs very simple.
Then, make the edge a little duller - and filéa next fish, now the edge slides above the ribs and dont slice thru them - and your filéa will be "bone free".

Sharp polished edges work nice in some materials - and bad in other magerials. Tothy edges works good in some materials - and bad in others...

You choose the type of edge you shall use (flat, convex, hollow) and then you choose how fine your edge needs fo be for the job you shall do 25, 10, 1 micron - or polished.

Of cause, this is what I do for jobs that need precision, for things that shall be conected to eachother and some on, not for every day fast jobs .

I like precision edges in angles and In my mind the angle are more imortant then if the edge is tothy or not. Very few people know what angle there is on their knifes. Most people think sharpening is to get the edge two sides to meet eachother - in what ever angle. When they meet, they start to cut...

I recomend my customers to by two simple Mora knifes. Their edges holds 11 degrees. I recomend them to make one of the knifes in 11 degrees exactly - and the other knife in 12 degrees exactly. Then start to whittle in some birch wood - and learn to know the differance in hiw they work, how much more force the 12 degree edge needs, how they penetrate the wood, and so on. After that test they know the differance between 11 and 12 degree edges. And - they also start to learn deeper knife and edge knowledge, hiw edges in different degrees work - and why.

2010 I show my sharpening tool Chef for the first time. Chef was the first sharpening tool ever with a built in protractor. This becouse Chef was also the first sharpening tool that could be adjusted for different blade width = Chef allways sharpen knifes with a fixed distance if 28 cm between the edge and the pivot point. So, it was very difficult to know what edge angle it was on your edge bexouse it was difficult to meassure the degrees.

The difference in material thicknes on the cutting edge between 10 and 11 degrees are less then 1/1000 part of 1 millimeter per side of the edge (the differance are, 0.055 mm behind the cutting edge 1/1000 part of 1 mm). Lets say that 1 degree add 2/1000 part of 1 mm on the cutting edge - that is not a lot of material - but - the cutting edge holds about 6/1000 part of 1 mm thicknes - and now you add 20% more material to the edge so it grows to 8/1000 part of 1 mm

The only way to go deeper in to knife knowledge is to know what degrees there is on your edge - and then use the knife your self and evaluate the edge. Then change the degrees - and evaluate the edge again.

If you do not know what angle there is on your knife and ghen change the angle - you do not know where you started, you do not know where you landed, you do not know how long Journey your edge have done - and what can you learn from not knowing? Nothing. You allways start from scratch .

If you know what degrees your edge holds - you understand WHY you need to change the angle, you also know how much you need to change the angle - and allready before you start the change of ghe andre you know the result of what you are doing - and from knowing - you can learn. You never start from scratch again.
That is why I create Chef - and later my other tools with built in protractor.

So, the problem to meassure the degrees on the edge also make people say that "degrees are not so important"... The important thing was to make the both side meet eachother - and no burr - and polish the edge so it looks nice...

This is my opinion and experiance of using knifes outdoors during 60 years in Scandinavia. Here we whiitle with our knifes, we never batoon them, bend with them or chop with them. If we need to chop we het an axe or use a chopper. Our edges hold around 20 degrees total edge. My chopper holds 26 degrees, my Forest axe holds around 35 degrees, and my splitting axe holds 40-45 degrees.

Metall cutting edges holds 90 degrees, axes holds 45 degrees, knifes holds 22 degrees and razors holds 11 degrees is a old saying here. The degrees decreese in halv in every step. Hair needs 11 degrees, wood needs 22 degrees, splitting needs 45 degrees - and metal needs 90 degrees to hold.

Thomas

[Mark Reich]

Thank you so much for such a delightfully informative post, Mr. Thomas!

It's great to hear of your experience from the other side of the globe!

[Ken S]

I second Mark's comments.

Ken