Hollow Ground Blade Vs Flat?

[Suicide]

Hi everybody,

What the advantage of using the hollow ground swivel knife's blade vs flat one (neat cut ends? easier and smoth pass of the scrolls? etc)?

And what the cases when using hollow blade should be preferred?

Thanks in advance!

[Ferg]

I have both. I use the hollow ground very seldom it seems. I have a multitude of width blades. Have several knives but my very most favorite is my SK-3 with a 1/4" angled blade.

Cuts the worst leather with ease in most instances.

ferg

Hi everybody,

What the advantage of using the hollow ground swivel knife's blade vs flat one (neat cut ends? easier and smoth pass of the scrolls? etc)?

And what the cases when using hollow blade should be preferred?

Thanks in advance!

[Suicide]

I have both. I use the hollow ground very seldom it seems. I have a multitude of width blades. Have several knives but my very most favorite is my SK-3 with a 1/4" angled blade.

Thanks, Ferg.

I just thought hollow ground may give sort of benefits while carving sharp/small radius curves and scrolls. Just my wild guess

[hidepounder]

I prefer hollow ground blades over flat grinds but not for the reason you might think. A hollow swivel knife blade is never used deep enough in the leather for the hollow grind to be of any real benefit. However, when using the knife I find that I like to place the tip of my ring finger into the grind. It's a comfortable spot which gives me a little bit of control when using the knife. With the exception of my SK3, all of my blades are hollow ground. It might be a mental crutch, I don't know....nor do I care, LOL! I like hollow ground blades.

Hope this helps....

Bobby

[Suicide]

I prefer hollow ground blades over flat grinds but not for the reason you might think. A hollow swivel knife blade is never used deep enough in the leather for the hollow grind to be of any real benefit. However, when using the knife I find that I like to place the tip of my ring finger into the grind. It's a comfortable spot which gives me a little bit of control when using the knife. With the exception of my SK3, all of my blades are hollow ground. It might be a mental crutch, I don't know....nor do I care, LOL! I like hollow ground blades.

Thanks, Bob! Interesting idea about holding knife that way, definitely have to try.

[Knipper]

I don't make swivel knife blades, but I was always curious about the "hollow grind" designation. For the ones I've seen, the 'hollow' is actually ground perpendicular to the edge, as opposed to parallel with it, as in a hunting knife. So, the hollow grind isn't really a factor affecting the edge at all (I think!...)which I believe is what Bob is referring to. The hollow ground blades I've seen still have a flat bevel along the edge like the traditional flat grinds do. I'm guessing the benefit of a hollow grind done that way lies in other areas, such as sharpening (a bit less material to remove) and perhaps slightly less drag through the leather. I'm under the impression that when swivel knives are used, the entire flat portion of the edge is not put onto the leather, but rather the blade is tilted a bit, having the effect of cutting with the corner of the blade. I would think that if the whole blade surface was presented into the leather, the leading edge tip would tend to get hung up. Pablo (Paul Zalesak) might have some good input on this, since he makes some beautiful swivel knives... Paul, do you notice any difference in making the cut with one or the other? Help educate an ignorant enthusiast! (me!)

Knipper

I prefer hollow ground blades over flat grinds but not for the reason you might think. A hollow swivel knife blade is never used deep enough in the leather for the hollow grind to be of any real benefit. However, when using the knife I find that I like to place the tip of my ring finger into the grind. It's a comfortable spot which gives me a little bit of control when using the knife. With the exception of my SK3, all of my blades are hollow ground. It might be a mental crutch, I don't know....nor do I care, LOL! I like hollow ground blades.

Hope this helps....

Bobby

[Suicide]

So, the hollow grind isn't really a factor affecting the edge at all (I think!...)which I believe is what Bob is referring to.

Hmmm... According to pictures I see, hollow grinding affects the edge, please have a look at attached pictures. At least edge's width is affected.

Edited January 19, 2012 by Suicide

[pabloz]

Hmmm... According to pictures I see, hollow grinding affects the edge, please have a look at attached pictures. At least edge's width is affected.

Actually this type of "hollow grind", being that it is perpendicular to the cutting edge, makes the two side bevels thinner in the middle where the concave grind is the deepest. It really does not affect the cutting edge as the cutting edge is the point at which the two bevels intersect. This is one of those things that comes down to personal preference and of all the various reasons told to me for its existence the most logical one I have ever heard is from Keith Seidel, "I also like a hollowground blade. Not for cornering, but for the ability to see wherethe cutting edge makes contact with the leather." This type of hollow grind can be done on most blades down to about .030" or .70mm thick, at which point the blade is too thin to grind much more. So by following this logic the thicker the blade the better advantage it has...the thinner the blade the less advantage it has. This would also be true for the other personal preference reasons. I do not put a hollow grind on the sides of my blades as they are usually thin "Sheridan Style" blades that are normally at or under 1/16".

Also, Please understand that I am presenting this for educational information purposes as requested by Knipper (see above) and not as a spam/ passive marketing attempt.

Thank you for taking the time to read my posting and stay SHARP,

PZ

[Art]

I have both "styles" of blade and don't see a difference. The advantage of putting vertical hollow grind marks on a blade seems to be more culinary, where the knife blade will release the food better when it has those vertical grinds. The disadvantage of the vertical grind is that under heavy use and sharpening, the blade will wear away at the intersection of the vertical grind mark and the edge. I haven't used one that much yet, but I guess it is possible. That would not be a real problem as the swivel knife is used more on the edges and seldom all the way to the middle.

Art

Actually this type of "hollow grind", being that it is perpendicular to the cutting edge, makes the two side bevels thinner in the middle where the concave grind is the deepest. It really does not affect the cutting edge as the cutting edge is the point at which the two bevels intersect. This is one of those things that comes down to personal preference and of all the various reasons told to me for its existence the most logical one I have ever heard is from Keith Seidel, "I also like a hollowground blade. Not for cornering, but for the ability to see wherethe cutting edge makes contact with the leather." This type of hollow grind can be done on most blades down to about .030" or .70mm thick, at which point the blade is too thin to grind much more. So by following this logic the thicker the blade the better advantage it has...the thinner the blade the less advantage it has. This would also be true for the other personal preference reasons. I do not put a hollow grind on the sides of my blades as they are usually thin "Sheridan Style" blades that are normally at or under 1/16".

Also, Please understand that I am presenting this for educational information purposes as requested by Knipper (see above) and not as a spam/ passive marketing attempt.

Thank you for taking the time to read my posting and stay SHARP,

PZ

[hidepounder]

So, the hollow grind isn't really a factor affecting the edge at all (I think!...)which I believe is what Bob is referring to.

Terry, that is what I was trying to say. The thin part of the blade created by the HG usually never comes in contact with the leather because only the tip of the blade is used. There are a couple of exceptions of course, such as when cutting a straight line. In that instance the blade is laid flat in an effort to get as much blade as possible in the leather which helps to prevent wandering. The other exception might be where a very thin blade is used on heavy skirting leather and the tooler is cutting very deep. But for the most part, the HG does not aid in making the cut.

So by following this logic the thicker the blade the better advantage it has...the thinner the blade the less advantage it has.

Paul, I agree that the logic would suggest that a thicker blade would benefit more than a thin blade from hollow grinding. In reality the opposite is true. The reason for this is that the length of the taper (to the cutting edge) on a thick blade is much longer than on a thin blade (assuming both are sharpened at the same angle). Consequently one would have to push a thick blade much deeper into the leather in order for the grind to make contact. I have a very thin Henley blade designed by Jim Jackson for finish cuts which is HG and the "grind" would contact the leather quickly in comparison to a thick blade (if I used it for that purpose, which I don't). So you can see that HG is really only effective on a thin blade with regard to cutting. On a thick blade the HG just looks good and provides a nice little spot to place the tip of the finger. And I think we all agree.....that is probably the only real benefit for any HG blade.

In this photo you can see the difference in the length of the tapers on the two HG knives. The 1/4" tapered blade is twice as thick as the 3/8" staight blade. They are both sharpened at the same angle. (sorry for the poor photo quality!)

Edited January 19, 2012 by hidepounder