Hello Mr Me2, I’ve been reading your very astute posts, and find them quite intriguing. It’s great to hear you are sharpening on stones, as that is my preferred method as well.

I’m sure there are more than a couple of us, so we’ll see who signs in. Sharpening and maintaining high quality kitchen knives on stones and leather hones is a subject of high interest to me. 

I’ve spent enough time with Murray Carter to have been his first apprentice, several years ago. I just got back from visiting him in his new shop, and had a swell time with him. He truly is amazing, and I’m forever humbled to know him as a Grand Master Bladesmith and friend.

I am pretty familiar with kitchen knives, especially Japanese carbon steel. I’m well connected with many friends who highly prefer Japanese carbon steel kitchen knives, and I have well over $10k worth of laminated Aogomi Super Blue, with which to appease them, ASAP. The only thing I lack is time to focus on it, which is mandatory. I’m not interested with anything that wouldn’t make Mr Murray proud.

So anyway, I’m really happy you’re here, and I apologize for not speaking up sooner. Please allow a late Welcome to the forum. I’m really looking forward to visiting with you. Hopefully we’ll have company.

I recently read a post by Mark Reich recommending Barkeeper's Friend cleaner. I bought a can and just tried it. I applied a little on a Scotch-Brite pad and worked on my two ceramic rods. One was a gift from Steve Bottorff originally from Smoky Mountain Knife Works. The other is an M3 I am testing for for Work Sharp Culiary. Both work very well, but eventually acquire the inevitable worn steel deposits.

In the past, I had good results removing the majority of this leftover steel with Soft Scrub and Scotch-Brite. The Barkeeper's friend got it all! 

Thanks for the tip, Mark.

Ken

Gentlemen, 

In response to a popular question of trying to make knives out of old files, I feel we should have easy access to this specific topic. Wal-la, here we go!

Many people use old files for their first attempts of shaping a blade. Some guys use nothing but old files, or rasps and make lots of knives. They look kinda neat when you don't grind all the checkering off. Actually, just buying a new file or rasp is still a pretty cheap-n-easy way to obtain a pre-hardened blank, but there are MUCH better options.

Grinding hardened steel is a chore, and it gets a lot trickier as the bevels get thinner. It's super easy to overheat the edge, or at least the tip. You may not even be grinding close to the edge, but the heat generated will flow to it's easiest escape route- the thin part. You will toast your first few blades, especially when you progress to finer abrasives. Files are brittle, with huge grain size too. They aren't heat treated to be knives, and it darn sure will show. At best, you'll drop it and it will break. At worst, you may be needing it to survive.

I would highly recommend buying simple steel bar stock instead. "10 series" tool steel is inexpensive and easy to heat treat. Something in the range of 1045 to 1075 would work well. You can buy annealed (soft) bar stock in any practical size, so getting a stick of 1/8" to 3/16" thick by 1" to 1 1/4" wide would save you a ton of work and worry. It doesn't matter how hot it gets while grinding. It's easy to harden when you're done grinding, and it's easy to temper in your kitchen oven after it's hardened. 

Honestly, I would never consider or recommend using files without annealing them, then harden and temper after grinding. You're still guessing at what steel your file is made of, so heat treating would be much more hit and miss. 

Since heat treating is the soul of a blade, there should be no guesswork involved. Properly heat treated low carbon steel will perform much better than Japanese Aogami Super Blue, or any other fancy steel, or any Unknown steel, without the proper heat treat, or at least something close. 

Starting out right is way more than half the battle, and I'd be horribly remiss for not saying so. Making knives ain't easy. Spending time making something that looks like a knife but acts like an icicle is pretty easy, but not particularly satisfying.

If you choose a steel that carries the properties you're looking for, sending it out for The Perfect HT, tailored to your specific application, is a snap. It's also much less aggravating than spending considerable time and energy grinding yourself a noodle out of steel. 

KNOWN steel is easy to find, even in the right size. If you choose a regular carbon steel, you can probably  heat treat it yourself, and come out with a very usable tool. 

Gentlemen, I must apologize for allowing one thread to contain a dozen topics. I'm new at managing a forum, but learning.

Please don't hesitate to start a new thread. Even if your topic is similar to another, I guarantee it will turn out to be completely different. 

This will surely aid us in finding questions and answers by specific authors, and keep everyone from having to read back through a thread to remember what context the thread morphed into.

That is all for now.


Get out there and have fun. 

We've always said that we've learned far more from our customers than they have from us so we're back to the well here. This subject concerns one of our industrial customers who developed questions concerning sharpening protocols after purchasing one of our ID75A instrument systems. They provided us with samples of both new and used edges that are used in one of the their many cutting/slicing operations.  The following picture was taken, by us, of one of their used blades. The blade is used in, what we would term, a planing operation. The blades are used to plane the surface of flat plastic bars. These blades are hardened tool steel, .125 inch thick and single bevel ground at 30 degrees. The customer refers to these blades as "skives". The following is an optical microscope image of the "flat" or backside of the blade. 

   

Not so pretty. We think that this edge has several problems but the question that we would like to pose here is this one; It would appear that the edge has rolled and that it has rolled toward the flat side of the blade (skive). This roll is bad enough that a fingernail can be hooked on it. Is this roll direction normal? From an apex structure standpoint it seems as if it might be but from an application standpoint (planing) it seems unlikely. Certainly this roll direction seems to be real deal killer in terms of a planing operation.

We're hoping that our woodworkers out there might be able to lend the benefit of their experience to this question.

Several years ago there was no affordable edge sharpness testers - NONE!  Yes, I know a Dixie cup with sewing thread pulled across it.

Today we have one.  That has a World standard - Mark and Vadim can compare their edges without physically swapping edges. Australia to South Dakota USA.

Lets move forward - how about a "Edge Retention" tester?  Mike, Mark R., and Vadim?  Lets cut rope (manila hemp).

Move forward again -  an affordable "laser protractor".  Six to 7 hundred dollar (Catra) is out of my range.  Google, laser pointers and etc the prices are reasonable. Strong enough to blind and damage a pilots eyesight on approach.  Jan is a copy of the Catra that Vadim uses possible at lesser monies?

Mike, you have demonstrated the ability to design, manufacture, package and carry a product to fruition. 

There is hope

Rupert

Today we celebrate a breakthrough in our sharpening at Knife Grinders.

Having improved our sharpening protocols based on SEM data studies,
we now steadily get the same or better edge sharpness as the Feather DE safety razors.

For quality mainstream steel, from Global and up, the edge sharpness is 20-35 BESS or near 0.05 micron edge apex width.
For premium high-end steel,  the edge sharpness is 15-20 BESS i. e. under 0.05 micron edge apex width.
Note that the Gillette DE razor has 0.1 micron edge and scores 50 BESS.

This level of sharpness is extraordinary for knives, and is more readily achieved by dedicated straight razor sharpeners.

An edge that sharp easily passes the top hanging hair tests, and the Tally-Ho cigarette rolling paper held horizontally push-cut test.

We can't tell you all details of our new sharpening protocol, but we've published the general description here:
Scanning Electron Microscope images for our sharpening protocols

Pictured is the first high-end knife Survive Knives GSO 4.1 in CPM20CV sharpened at 24 degrees included, using the new protocol.
CPM-20CV is Latrobe version of Bohler-Uddeholm M390
This knife scored 15-20 BESS i.e. is sharper than the best Feather razor, and the Feather razors are the best of all DE safety razors.




Up to this day we used to add a band-aid with the company logo returning knives to the customer as a marketing gimmick.
Now I am thinking of adding a prosthetic finger

new to forum.  I am a knifemaker in North Carolina.   found a link to this forum on the Cliff Stamp's site "Towards 0.1 Micron."  I make smaller knives for the kitchen usually of O1 I heat treat myself, usually to Rc62-65 hardness range.
on knife forums I hear talk of ceramic stones.  what exactly are they talking about?  are these just stones made of synthetic alumina?


Scott Livesey
"Just an old sailor glad to be home from the sea."

We have had much discussion about polished vs. toothy edges for knives. What about scissors?

Whereas knives have one edge, usually with two bevels, scissors have two edges. Should each edge be sharpened the same way? Should the edge which supports the material being cut have a toothy edge to help prevent the cut material from slipping?  What about the other edge? Should both edges receive the same amount of polish?

I have read that there is an advantage in using two grinding wheels when sharpening scissors. I have also read that often only the coarser wheel or belt is used.

I have seen machines which sharpen scissors with small diameter grinding wheels, large wheels and flat grinds.

Thoughts?

Ken

FYI, we've added a sharpness chart to the Sharpening Resources section of our website knifeGrinders.com.au
Includes data for all traditional sharpness tests.