bevel angle?

K

KD Knife works

Joined
Mar 8, 2016
Messages
4
hey guys. starting some new prototypes today, and normally i would just sacrifice one of my blanks to find the right degree for my beveled adge. but i dont want to do that any more. i was just wondering if there was a way to figure you angle out a head of time,or what do you guys normally do for your first prototype knife thanks guys
 
Use this:

http://www.calculator.net/triangle-calculator.html

You can put in just the sides of the triangle and it gives you angles. Make a diagram of your knife cross section. Even if it is a complex design, you can still break it down to 90° triangles and rectangles by subtracting the thickness behind the edge from the total thickness.
 
I hate the drawings, math , and the mock up. My opinion is grind your blade slowly and revel in it's perfection...stopping a little short for heat treat of course. There will always be more steel but there may not always be more time. Yes, I am completely serious. Another opinion from an older guy. Larry
 
LARRYZ10 said:
I hate the drawings, math , and the mock up. My opinion is grind your blade slowly and revel in it's perfection...stopping a little short for heat treat of course. There will always be more steel but there may not always be more time. Yes, I am completely serious. Another opinion from an older guy. Larry
Click to expand...

It sound like KD is setting up for production, of sorts. I can understand why he might want to have a better idea about how things are going to go together than trial and error.

I'll bet you have a natural knack for seeing what you'll come out with. But not everyone is as lucky.
 
LARRYZ10 i agree with you but if your in the middle of grinding a bevel and your already at the center of your knife but you want to go down another 1/4 inch what do you do? stop what your doing to adjust the angle of your grinder or jig. i hate math and triangles to but that way seams a little easier. thanks guys
 
KD Knife works said:
LARRYZ10 i agree with you but if your in the middle of grinding a bevel and your already at the center of your knife but you want to go down another 1/4 inch what do you do? stop what your doing to adjust the angle of your grinder or jig. i hate math and triangles to but that way seams a little easier. thanks guys
Click to expand...

You could always just... freehand grind at a more acute angle. I guess I'm having trouble seeing the problem here. I always first grind close to my center line at a rather obtuse angle and then take the bevels progressively more acute until I have them where I want them.
 
KD Knife works said:
LARRYZ10 i agree with you but if your in the middle of grinding a bevel and your already at the center of your knife but you want to go down another 1/4 inch what do you do? stop what your doing to adjust the angle of your grinder or jig. i hate math and triangles to but that way seams a little easier. thanks guys
Click to expand...
I'm not trying to speak for Larry but a lot of us don't use jigs. I tried when I first started but it didn't work well for me. The beauty of freehand is that your adjustments are immediate. If you've already made it to the center and need to take the grind higher then you just put most of the pressure on the top of the grind. I typically take my grind almost as high as I want it and leave a little meat on the edge. Then I start working the edge down to the thickness I desire. I find freehand grinding to be faster and, with a little practice, easier also. I'm not knocking jigs at all. It's just that I didn't have much luck.
 
Purchase a Bubble Jig then there is no guessing or correcting or wasted blades to through away. Its the precise easy way to grind bevels.

Regards, Fred
 
I don't use jigs or any measuring device to get the bevel angle. I just grind it from the edge to wherever I want it to stop .... and that is the angle. In some complex Japanese grinding and polishing, the difference in an angle from one place to the next may be only a few hundredths of a degree. You can't get that from a jig. You get it by eye and feel.

I have regularly posted that the angle of the primary bevel is inconsequential. It is just a factor of the height of the grind and the thickness of the blade. You can't change the angle without changing one of those two things. Thus, pick your stock thickness, then decide your grind type ( FFG, sabre, etc.) and grind/file away. After the bevel is made, if you just have to know what the angle is, work the math or look at one of those charts.

Also, the angle isn't constant down the blade. The thickness reduces due to distal taper and the grind height varies as the blade tapers in width. This makes a continuously changing primary angle. If you worked off a fixed jig and filed/ground the angle at an exact number ( say 7.1°) the edge would be wide and flat at the tip and go to a zero edge at the plunge.

I often say that a new maker who builds a filing jig to make his blades is like a guy who goes to a nude beach with binoculars. He may see a close up of a cutie in the buff, but if he would set the binoculars aside, he would see the whole beach full of cuties. The jig just limits you to a small range of only one thing.


The exception is Fred's Bubble Jig. It only guides you, it doesn't limit you. You might even say it is limitless. I would say that it will speed up the learning curve a lot.
 
I always grind freehand. I don't even use a work rest unless I cut in a swedge. In most cases it is FFG. An issue I have had in the past, and still make a conscious effort to avoid, is making the tip too thin for a hard use knife. I used to grind the edge post HT to about .010" from heel to tip. That would leave too delicate a tip for my tastes. So I leave an increasing thickness from the belly towards the tip. That means when I sharpen the blade the secondary bevel angle will change (become more obtuse) as it progresses towards the tip in order to keep enough strength at the tip. I can't do that with jigs and calculated angles from charts. I do it all by eye and feel. Most of my knives are one-offs or prototypes so this is my procedure for all of them. My thinking is this. I want to use as much of the blade as I can for the primary bevel. That means FFG. If I go halfway up the blade I'm leaving some performance on the table. I adjust the final edge thickness before convexing the edge according to the intended function of the knife. This is the way I work now. It could change in the future as I continue to learn.
 
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If I could please...just grind each side of your knife to approximately what you want and make the other side the same. Then refine your grind on both sides and finish. if you wish to manufacture knives then hire a machinist. I don't claim to be an artist but there are plenty of manufactured knives out there. Their knives don't interest me. Larry

VgYxILLm.jpg
 
LARRYZ10 you are absolutely right. i have always done my bevels by hand(file and jig). i just got my new belt sander hooked up Friday, and to be honest with you it scares me a little bit to do them by hand because i know ill fuck one or two up. in the future i would love to do them by hand just scared to take that first step. if you dont mind me asking what grit do you use? i was in the shop last night practicing making a bevel with 120 grit. thanks
 
Stacy E. Apelt - Bladesmith said:
I don't use jigs or any measuring device to get the bevel angle. I just grind it from the edge to wherever I want it to stop .... and that is the angle. In some complex Japanese grinding and polishing, the difference in an angle from one place to the next may be only a few hundredths of a degree. You can't get that from a jig. You get it by eye and feel.

I have regularly posted that the angle of the primary bevel is inconsequential. It is just a factor of the height of the grind and the thickness of the blade. You can't change the angle without changing one of those two things. Thus, pick your stock thickness, then decide your grind type ( FFG, sabre, etc.) and grind/file away. After the bevel is made, if you just have to know what the angle is, work the math or look at one of those charts.

Also, the angle isn't constant down the blade. The thickness reduces due to distal taper and the grind height varies as the blade tapers in width. This makes a continuously changing primary angle. If you worked off a fixed jig and filed/ground the angle at an exact number ( say 7.1°) the edge would be wide and flat at the tip and go to a zero edge at the plunge.

I often say that a new maker who builds a filing jig to make his blades is like a guy who goes to a nude beach with binoculars. He may see a close up of a cutie in the buff, but if he would set the binoculars aside, he would see the whole beach full of cuties. The jig just limits you to a small range of only one thing.


The exception is Fred's Bubble Jig. It only guides you, it doesn't limit you. You might even say it is limitless. I would say that it will speed up the learning curve a lot.
Click to expand...


But if more new makers would at least look at the charts and think about the angles, you may have fewer first knives with the 45Degree angled bevels.
 
True. Most are twice as thick as needed and the grind line goes up barely any at all.
 
Matt,

Based on the work you've been showing recently, it looks like you've gotten past the impatience and laziness.
 
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