Flat ground vs Hollow Ground

Nathan House

Nathan House

Joined
Feb 14, 2000
Messages
1,204
I am new to knife makeing only been grinding
for about a month My big question is
what is the best cutting and has the most
strength the flat or the hollow ground blade
I would also like to hear which do you think
is harder to do,I have ground both
please give me some input.
 
Generally, a hollow grind will out cut a flat grind while the flat grind will be stronger. Some say that the flat grind isn't beat by the hollow grind that much with respect to cutting so the added strength compensates for any loss in cutting power. Then there is the bit about linear expansion vs. non-linear and sharpening which may make a difference to some. Which is easier to grind? I don't know!!! I'm new to grinding too and I am sticking to flat grinds for a while.

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"Come What May..."
 
This is the opinion of a piker, newbie, FNG, et al...while the flat grind appears simpler to construct on a flat bar with little varience of structure, the hollow grind is without a doubt the more esthetically pleasing to the eye. It bends the light to refract the lines in a way that the more ulitarian flat grind does not. I know that this will probably bring a rain of horror and disgust from the flat grinders and forgers but it is only the opinion of the above listed.

For a combat knife I would prefer something that would penetrate armour to a killing depth, if required, and stand up to all the abuse an infantrymen could inflict upon it. Heavy pointed with FLAT ground edges would suit me best but I've seen hollow ground knives that appoach the same perfection.

For a field knife I would prefer something a little more suble but have similar strengths and for that reason would choose a hollow ground blade.

Length is personal regarding what you want the blade to do and how you want it to perform.

I realize that I have more than likely POed a number of you by now with my incoherent ramblings but I just wanted to share some thoughts and get some feedback.

With that I bid you

All the Best

Dileas Gu Brath
 
i like both flat grinds and hallow grinds. although right now i can only flat grind. i find flat grinds to be very tough and better for a large knife becuase big knives should be strong, like a bowie. but hallow grinds are good for small knives becuase they can be sharper, and for a small knife becuase it needs to be sharper to cut, becuase it doesn't have the weight of the bigger knives.
their is also convex grinds too! they are stronger than flat grinds.

[This message has been edited by magnum .44 (edited 05-29-2000).]
 
This is a question that many long time makers avoid, as it almost always comes up with different answers and each maker walks aways still thinking their choice is best.

I have come to believe, so this is my opinion and nothing more, that different grinds are best suited to the purpose each individual knife.

Also, many times you will have a possible customer depending on a certain kind of grind. Because of this, I have opted to learn both hollow and flat grinding techniques.

Just for arguments sake, I have to disagree a little with Dav's post, as I have seen many blades with classic lines in a flat grind that just wouldn't have looked the same hollow ground. But, beauty is in the eye of the beholder...

As far as one being easier than the other: Ask a flat grinder, and it's almost always going to be the flat grind that is harder to do. Ask a hollow grinder, and the story flips 180 degrees.

I think the only way either one of them are "easy" is if you practice, practice, and practice.

So, to encompass my rambling with a point...I'd have to say, try to learn to do both and become very fluent with doing them both. If in the future you decide that you want your style to be definitive as to one style then you can, but otherwise you can grind either style with confidence.

Nick
 
Nick
words well spoken,I agree with you
100 percent,I have only been at it a month
and have learned both so i can do them
if a customer want either one you can do
it, makes you a more well rounded knife
maker. Nathan House
 
Uh, it depends on the intended use of the blade. A razor is hollow ground, a survival knife is not.
A flat ground knife will "tend" to hold its edge longer, a hollow ground blade "tends" to be sharper.
As you sharpen a flat ground blade over time, the edge gets thicker. A hollow ground blade will not do this as quickly. This is over years of use.
Ease of grinding? Making the plunge cut is a little more difficult on a hollow grind but after that is down pat, just stay in the hollow. On the flat ground blade it is more difficult (at first) to keep the grind lines straight.
A flat ground blade tends to be a stronger blade. There is more meat left on the blade.
As stated in the beginning, it depends what the intended purpose is to decide which is "better".

C Wilkins
 
Wow! what a loaded question. Intents, strength, sharpness, durability, asthetics... Too many factors to create an all out best way to do business.

How's this for a twist, there's another grind. The convex grind. Best described as the opposite of the hollow grind. The edge is not sharpened flat as with the flat and hollow grind, but an extension of the sides to meet and make an extremely keen edge. Read about it, tried it, liked it. However, the resharpening is not as easy. But, Very Sharp.

Sorry, No answers, just thought I'd add a twist....

Dan
Hannon Bearpaw Knives http://www.freeweb.pdq.net/dhannon/hannon.htm
 
The convex grind, or more correctly the cannel grind is made using the slack belt portion of the grinder(no platen).

Of the three grinds mentioned (sabre grind is variant of a flat grind), this is the least sharpest of the three. This is typically used in a "brute force" sort of application such as an axe or possibly a heavy sword. This grind will hold its edge for a very, very long time but will not take a keen edge.

I suppose of the three grinds mentioned, if there were anything such as compromise then the flat grind would be the closest to being between the two extremes (cannel and hollow).

The cannel grind is not to be confused with the convex or Moran edge that we like to put on our blades.

Oh, and then there is the chisel grind.....

C Wilkins
 
I like them all, I mostly use flat on hunters and meat cutting knives because they need to cut to the bone. My first thick hollow ground art bowie wouldnt carve the thanksgiving turkey but it would shave hair with the keen edge. The shoulders stopped it from sinking deep. A hollow ground will skin nicely because it is so sharp. I started using thinner stock 1/8" or even thinner, for flat ground small to medium sized knives. They get shaving sharp and easy to sharpen. My test bowie has a slight convex almost flat grind and easily passed the ABS Journeyman test which includes chopping a 2x4 in half twice and still shave hair. My best salesman works for Washington State Fish and Game. He uses one of mine with a thin flat like a mirror blade."It outcuts any knife Ive ever used" I make art knives and daggers with hollow grinds because they look so good the way they pick up light. Also daggers need hollow grinds because they are about 1/4" thick and would never get sharp at that steep angle. I am making another grinder that has a 14" drive wheel w/varible speed 1.5 motor. It should be a good compromise. Isnt that what Tom Mayo uses? I like those grinds alot. All the way to the spine. Later, Bruce
 
Howdy,

I like both Grinds myself,,,,,i guess it depends on what grind i use for the Style knife i am making really. I Try to design stuff that can be had with either grind depending on customer preference. But i do think the Flat grind if done properly has the advantage in certain Performance issues.


As far as which one is more difficult to grind. Both are equally as hard if you dont know how to grind them. But for me personally
hollow grinding is Boring because its so easy to do,, Flat grinding is a bit more of a challenge to do right because of the increased surface area that needs to be ground.

my .02

Allen

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Allen Blade
Spokane,WA USA

" You can make great knives and sell a few, Or make Great AFFORDABLE knives and sell many"
WEB SITE : http://hometown.aol.com/bladecutlery/index.html
 
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