BRKT Bravo I Edge Angle and Thickness Studies

E

effer

Joined
Feb 13, 2009
Messages
797
Had some free time to kill, decided to check why MY Bravo 1 was such a good cutter.
Measuring thickness and angle of convex grind is not an easy task. I've seen recommendations to use candle wax and some things like it, but I was having troubles getting accurate measurements with that.

I decided to use J-B Weld Stick. As many might know, it applies as a putty and hardens like metal (more like hard plastic). I spayed some WD-40 on the blade, so JB won't stick to it and put JB to work. I let putty harden for several minutes, then removed it from the blade. To get an accurate edge profile I used sandpaper (80-220-400 grit) to cut the top uneven part off. After this procedure I verified the profile by inserting the knife again. Perfect fit. I have marked 1/4" distance from the very edge and took a high-res picture with my camera.

Here is the picture:

1.jpg


Then I used photoshop to outline blade profile and calculated the angle and thickness results. Here is what I came up with:

2.jpg


Now, keep it mind that this is not a Brand NEW Bravo 1 straight from the shop. I have sharpened it in the past using sandpaper and mousepad (no powertools). I doubt that I removed too much metal, but still keep in mind that it is not 100% stock original.
 
Ok, we have some sound data here I think. Anyone care to interpret it and/pr put it into real world perspective some of us mathematical bleepards can easily follow?

:rolleyes:
 
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Rogue01 said:
Ok, we have some sound data here I think. Anyone care to interpret it and/pr put it into real world perspective some of us mathematical bleepards can easily follow?

:rolleyes:
Click to expand...

The problem is that you can NOT apply the translation of those numbers to a stock Bravo 1, because mine is not new and been sharpened several times. I might have (most likely) thinned down the edge and lowered the edge angle in the process. I have no clue how much difference there might be from a stock knife.

Here is what I can say about MY B1:

I was always wondering what made My thick B1 to perform at such high level. Well, now looking at my pictures and measurements, it is easy to see that angle of the edge is quite low. First 1/4" of edge (and even further) looks almost like a scandi grind (or zero flat grind) with low angle, though there is definitely a slight convex curve there.
Low edge angle (21 inclusive in first 1/16") has it's advantages and disadvantages. Advantage is the cutting ability. Lower the angle, the easier edge goes through material. Disadvantage is edge toughness. Lower the angle, less steel supports the edge and edge chips and rolls easier, than at higher angles.

At .215" stock my Bravo 1 is a thick knife, but it outcuts many other thinner knives in tasks like making fuzz sticks, cutting thin rope, paracord and others. It outperforms other knives, if task does not require a deep cut, because there is very little drag added due to thickness and most of it is compensated by smooth convex grind. But cutting a tire for example (I have never done it), I imagine Bravo 1 will be a pretty bad performer due to the spine thickness.
B1 cuts fresh meat fine, but cutting fruits and vegetables is not good (feels more like chopping).
21 degree edge is great for cutting, but not good for abuse. I haven't had any problems with the edge yet, but I definitely will think twice now before doing anything stupid with it.

What's the advantage of the thick spine, if edge is so thin? The only advantage I see is in batoning and overall blade toughness. Haven't pried anything with my b1 yet, but I did some batoning. Edge holds up pretty good and thick spine helps split the wood. Other than that, thinner blade sure is better for cutting or slicing.

For playing in the woods (mostly fire prep) I like my B1 a lot. I choose a knife with thinner spine for the kitchen.
 
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Thank you for expanding your ideas. Your overall assessment of the Bravo 1 makes sense, in my opinion.

I suppose there maybe is a small difference between your Bravo 1 and a brand new one, but I would imagine it to be negligible.
 
Here is a picture of the same Bravo 1 edge profile cast on top of Ka-Bar Short (5 1/4") USMC knife. Not the best picture, but you can see the difference there.


3.jpg
 
That might explain why some Bravo 1's have a tendency to roll during batoning. I wonder if a balance can be found between a thick bladed bushcraft knife thinner bladed slicing knife.

I've used my Bravo 1 in the kitchen, and even though it feel clumsy at times, it does the job. I've also used it in light bushcraft chores making tent stakes, and while it did a good job of cutting the stakes to size (using a baton) I ended up using an old kitchen paring knife to whittle the points with because the Bravo 1 felt too awkward for that task.

You could almost argue whats needed is a 6" thick bladed wedge shape knife for batoning/wood chopping and a thinner 4" slicer knife for general use, but then you could also argue that carrying a hatchet along with the 4" knife would also work.
 
Rogue01 said:
That might explain why some Bravo 1's have a tendency to roll during batoning. I wonder if a balance can be found between a thick bladed bushcraft knife thinner bladed slicing knife.
Click to expand...

Actually, there are a lot of knives in between. If you know what you want, you can find a knife with almost any spine thickness and edge geometry. There are also a lot of custom makers on this forum that can make a knife to your own specs.

One can try introducing a "Balanced knife", but it doesn't mean that it will be perfect for everyone and for every situation. There are too many variables and crap load of individual opinions.

KnifeNUTs don't always choose the most logical route either (including myself) :)

Rogue01 said:
You could almost argue whats needed is a 6" thick bladed wedge shape knife for batoning/wood chopping and a thinner 4" slicer knife for general use, but then you could also argue that carrying a hatchet along with the 4" knife would also work.
Click to expand...

I like my B1, but I also have a combo. 7" knife for abuse and 3" for fine tasks. Combo cost me less than half of Bravo 1, but will outperform this single knife for sure. I can smash 7-incher into rocks, kill the edge on it, but it still could be used for some batoning and I still will have my 3-incher razor sharp. When at home I could put something resembling an edge on the 7-incher using angle grinder and strop my 3-incher on leather in 5 minutes. Not saying that this is what I do, but it could've been the easiest (maybe optimal) route. One thing that B1 would have over combo is weight (around 5oz difference there).

You can have $15 axe and $15 Mora and at the end of the day be better off than some people using a single $400 knife. Add a $15 saw and combo performance might double. But that's not the point... is it?
 
ou can have $15 axe and $15 Mora and at the end of the day be better off than some people using a single $400 knife.
Click to expand...

Ain't that the truth. Before I had the Bravo 1, I used a buck 110 I bought for $20.00 and a Buck 119 I found in the seats of an old Jeep I bought years ago. They still serve me well today, while the Bravo 1 that I paid over $200.00 for sees little use.
 
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Nice write up. I think your Bravo is pretty typical. Mine also had and still has a very fine edge and is ground pretty thin.

The thick spine does make it baton better and if done with good technique the edge should not take any damage from this. The thick spine also makes it stiffer and sturdier, but like you said it makes the knife ineffective when cutting hard vegetables. It does work great on fresh meat though and I've used it to skin and quarter reindeer while hunting.

Never had any issues (chipping/rolling) with the relatively thin edge on mine.

Sverre
 
Yikes! that's the same edge profile as my Scrapyard Regulator.
And it took me a few hours on a belt sander to achieve that.

If blade geometry is anything near this good on a stock Barkie, no wonder people like them.

Capture_00001.jpg



(Now I want a Bravo:grumpy:)
 
Awesome idea Effer with the JB! It's kind of costly and time consuming but sure beats all the other "home grown" ideas I've heard on here. It works great for making a point and having evidence to show everyone too. Very creative. That looks like a nice edge on that Bravo 1 too.
 
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