The Grind II

[El Pescador]

If you want to know how to make a great edge and you don't want to muck around the BS, a microscope helps a lot, initially. Once you know how to obtain a good edge, it is less important. If you want to make a great knife the first time, you don't want to dick around reinventing the wheel.

+1 i have a jewelers loupe and it has made a big difference.

 

[Marko Tsourkan]

Here is a little trade secret - a magnifying visor. Hands free and lets you see the edge very clearly.

 

[tk59]

But that's like cheating, Marko...

 

[Marko Tsourkan]

Why? It doesn't set the angle for you. You periodically look through the visor at the bevel for any irregularities, such as width, burr, etc. I find it very useful, particularly because my right eye has 80% vision, so looking at tiny bevels strains my both eyes.

 

[Salty dog]

If you want to know how to make a great edge and you don't want to muck around the BS, a microscope helps a lot, initially. Once you know how to obtain a good edge, it is less important.

If you want to make a great knife the first time, you don't want to dick around reinventing the wheel, you get some specs. If you want to cook something right the first time, you get a good recipe. It's all the same, really.

That was a friendly jab gently pointed in your direction.:tease:

 

[Marko Tsourkan]

That was a friendly jab gently pointed in your direction.:tease:

I am the last person who wants to reinvent a wheel, but I do like to tweak it a little bit. So far, it seems to have worked.

 

[tk59]

That was a friendly jab gently pointed in your direction.:tease:

Well, I definitely felt it! :bat:

 

[jmforge]

After reading this and other threads, I have a question. With the talk about thinning out the blade above the edge and having a shoulder up the bevel to prevent sticking, but one that is blended, it almost sounds to me like you guys consider the ultimate geometry on a dual bevel blade to be something akin to a VERY shallow hollow grind that goes part of the way up the blade and then has the shoulder rounded over. I am talking about a hollow grind like one that has maybe been made with a wheel the size of a large tractor tire. Much shallower than the grind on the back side of a single bevel Japanese knife. Have any of you ever thought of it in that way?

 

[JohnnyChance]

You mean like a wheel like this?

[video=youtube;aU6u80Hyw5Y]http://www.youtube.com/watch?v=aU6u80Hyw5Y&feature=player_detailpage[/video]

I have thought about it that way, kinda like a half-hollow or quarter-hollow razor grind. Problem is most makers don't have giant wheels (MC does, but does he grind his blade faces with them or just edge bevels?), so they achieve similar grinds in other fashions.

 

[jmforge]

Maybe bigger than that. Those are the size of the wheels you see in the OLD restored shops in places like Solingen and the other videos Ihave seen of Japanese shops and the guys still moves the blades around a bit to get flatter grinds on them. That looks like the size of wheel or maybe a bit larger that I would want to use to grind the back of a single bevel knife. If you want to see a cool video, there is one out there somewhere of a guy in Solingen grinding a sword blade on a wheel that size or maybe bigger, but it is an OLD water powere wheel and he is wearing this huge metal contraption that I can only describe as "grinding boots" The look like the legs of a robot from a bad 1950's sci fi flick and the guys uses them hold the blade steady and rocks forward into the wheel. I wonder of you could get a similar effect to what the guy is doing in this video with say a plten that is curved to simulate say a 48" wheel? It would require a steadier hand than I have right now. I would still have to do a LOT of hand sanding. LOL

You mean like a wheel like this?

[video=youtube;aU6u80Hyw5Y]http://www.youtube.com/watch?v=aU6u80Hyw5Y&feature=player_detailpage[/video]

I have thought about it that way, kinda like a half-hollow or quarter-hollow razor grind. Problem is most makers don't have giant wheels (MC does, but does he grind his blade faces with them or just edge bevels?), so they achieve similar grinds in other fashions.

 

[tk59]

It would be interesting to try out a blade with a very slightly concave secondary bevel. The obvious problem with that design is the trade-off of either inherent weakness of the blade near the edge or more thickness overall. I wouldn't buy a knife with a concave secondary because I would be unable to maintain that secondary bevel and I have knives that cut with virtually no effort and separate food well already. I do have a Glestain which is built like a traditional Japanese knife where one entire face of the knife is hollow ground and the other is convex. That is a nice design but most people don't have either the patience or the aptitude to learn how to use a knife ground in that fashion.

 

[Dave Martell]

That could be why Murray's knives do so well in this test, he's using his large water wheel to grind in the bevels making a slight concave.

 

[tk59]

That could be why Murray's knives do so well in this test, he's using his large water wheel to grind in the bevels making a slight concave.

I have two Carter 240 SFGZ's sitting here. I've checked all along the bevels of both. One of them has a small (~3 cm worth) area toward the heel on one side of the knife that is slightly concave. The rest is essentially flat or roughly convex (due to several flat areas that are somewhat blended together).

And yes, these will outcut everything else I've tried other than a modified Del knife I also have sitting here.

 

[jmforge]

I spoke with Nathan, the guy who was selling those curved platens on Blade forums. He has a 36" version left over but no 48's until he makes the next batch maybe early in 2012. That got me to thinking about maybe one as shallow as a 60" or even 72" radius. The 36 and 48 inchers give you what might be called the classic old school Solingen or Sheffield grind like you were using a big wheel, but since the blades we are talking about are so much thinner, I would be inclined to look at an even larger radius. The 36" one might be good for doing the backside hollow grind on a single bevel knife.

 

[jmforge]

I have two Carter 240 SFGZ's sitting here. I've checked all along the bevels of both. One of them has a small (~3 cm worth) area toward the heel on one side of the knife that is slightly concave. The rest is essentially flat or roughly convex (due to several flat areas that are somewhat blended together).

And yes, these will outcut everything else I've tried other than a modified Del knife I also have sitting here.

that blending of flats is how Japanese sword polishers set the bevels which are normally "zero" ground with a slightly convex profile. But since we are talking about a few hundred dollars for a finished knife as opposed to a few thousand just for the polish job, the blending will naturally be a bit more rudimentary on a kitchen knife. The effect is the same, I would think.

 

[tk59]

I spoke with Nathan, the guy who was selling those curved platens on Blade forums. He has a 36" version left over but no 48's until he makes the next batch maybe early in 2012. That got me to thinking about maybe one as shallow as a 60" or even 72" radius. The 36 and 48 inchers give you what might be called the classic old school Solingen or Sheffield grind like you were using a big wheel, but since the blades we are talking about are so much thinner, I would be inclined to look at an even larger radius. The 36" one might be good for doing the backside hollow grind on a single bevel knife.

If you want to know how it's done with platens, ask Butch. He's made several already.

 

[jmforge]

Yes, but Butch actually knows how to make them and has the skills and tools to do it himself. I am somewhat inept when it comes to machine shop stuff. LOL

If you want to know how it's done with platens, ask Butch. He's made several already.