Advice on bevels

Jellis11

Well-Known Member
Hey guys, back again with even more questions. As some of you know, I've been fighting the bear for the last week trying to figure out my grinder and how to cut nice clean even bevels. So, that being said, as a beginning knifemaker, what "type "of bevel should I be shooting for? To the best of my knowledge, I have seen three different "basic" bevels that I could do (I only have a flat platen at the moment) and PLEASE correct my terminology if I am wrong, but

1. A Scandi (Scandinavian?) grind where the bevel is about 1/3 the width of the blade and follows the curvature of the belly
2. A flat grind that is maybe 1/2 or more the width of the blade and the top side of the bevel runs in a straight line from ricasso to the tip ( What is this called?)
3. A full flat grind (?) the bevel runs nearly the full width of the blade.

I believe that at least part of my problem has been that I have been concentrating on creating a bevel with a straight stopping point (#2) and of course my straight line looks like something a two year old might do.

I'm working on implementing the tips and advice given to me on other threads, but I don't want to be spinning my wheels trying to grind a bevel that should be saved for someone with more experience.

Advice and/or comments?

Thanks,
Jeff
 
Jeff, you are asking great questions. I'm a relative newbie, too. I've been at this for a little over two years and I can only relate it to my own experiences and the way I understand things, so if it seems like I'm always relating your questions to my processes that's why. Please don't take my advice as the gospel, rather take it as coming from a guy who very recently got over the hurdles you are facing now. Keep in mind that I grind freehand. I don't use the tool rest or jigs.

There are two different ways I have found to approach grinding. As you progress you will begin to use both of these, but it helps to think about things separately. This gets to your question is a round-about way.

1. grinding in a straight line

2. following the curve


So, how do you do them?

1. Straight: I found that grinding in a straight line was the best way to learn, even though it makes the least amount of sense. Why? Because when you first begin to grind, establishing a flat bevel ASAP is the key to it all. Put the blade on the belt and draw across the belt in a perfectly straight light. DO NOT follow the curve. We'll worry about the tip later. All we care about is carefully placing the blade down on the belt as slowly and gently as possible so that the blade does not rock up or down, or left or right. It goes down onto the belt at the exact angle you want and then you draw it across the belt with no change at all to the angle in any direction. If you do this repeatably you will create a flat bevel. Every pass, that bevel gets wider and wider until you have this nice FLAT bevel. Laying this wide bevel down the belt perfectly flat becomes child's play. Don't worry about the bevel angle. You'll adjust that as you go up through the grits. But once you have this flat bevel, the knife darn near grinds itself. It took longer to read all that than it does to do it. We're talking five or six good passes. Now you can begin walking your bevel up or down and can begin to follow the curve of the edge.


2. Follow the curve: A Scandi grind is nothing more than following the curve without ever changing the angle. As you draw the knife across the belt, you maintain the same angular relationship between the edge and the belt. Every grind will require following the curve. The reason I don't start this way is because as you follow the curve, you take away steel from the tip. When you are just starting out, having a hunk of metal on the tip gives you some protection against doing something really stupid to the tip, like pulling the handle away while you press in at the tip.

If you begin with the straight across method you will have to start following the edge and blending each pass, but it's easy to do once you know where your bevel is.
 
Quick question, Jeff. Are you marking your center lines? Make sure to mark the center line on the spine as well. The line on the spine is your easy reference to make sure the tip is staying centered and that your bevels are the same on both sides.

As you grind, your eye should be focused on your center line and the gap between it and the belt. This is exactly why we grind edge-up. If you watch that line like a hawk, constantly measuring that gap with your eye as the blade moves across then you will be making flat bevels. In the beginning that line will be wobbling all over the place. If so, that's your problem. That line and the gap between it and the belt needs to be rock steady as you move the blade. Sharp belts and an eagle eye on this line and all those crazy problems start to go away.
 
Quick question, Jeff. Are you marking your center lines? Make sure to mark the center line on the spine as well. The line on the spine is your easy reference to make sure the tip is staying centered and that your bevels are the same on both sides.

Thanks John, great tips! I am marking the blade edge, but never thought of marking the spine. I haven't had a lot of trouble getting an initial bevel (1/2" or so) down to my scribe lines on the blade edge....my trouble begins when I try to start "walking" that bevel down. I'll get to a decent spot and find that the line is uneven or curvy, so I try to adjust by hitting one end or the other and it just all goes to pot. Hardest thing so far is getting that straight horizontal "stop "between the bevel and flat. Its killing me!
 
my trouble begins when I try to start "walking" that bevel down. I'll get to a decent spot and find that the line is uneven or curvy, so I try to adjust by hitting one end or the other

STOP! There's your problem.

It's going to be curvy. You'll have high and low at times. Do not, under any circumstances, try to fix this by hitting the low spots only. That way lies certain destruction, Bilbo.

The only thing that fixes curvy lines are straight lines. On the the next pass, pay super duper special attention to making the straightest, flattest pass you ever though possible. Apply the tiniest amount of pressure toward the spine. You do not want to rock the blade toward the spine. You want FLAT FLAT FLAT with a few ounces of extra pressure on the spine side of flat. Make your pass. Look at it. If it's not perfect, do it again. Now you see that the bevel has walked up by a good bit. Go back to perfectly flat with no extra pressure. Do that a couple times. You only want the bevel walking when you intentionally do it. It doesn't just magically walk up the blade, leaving you with this gorgeous flat bevel with a perfectly straight line at the top. No sir, that is accomplished one single pass at a time with a few ounces of very intentional pressure and straight movement.
 
Very few knife makers have perfect grinds prior to heat treat. In fact, probably none. You simply do not finish the blade to perfection and then heat the crap out of it. It will change somewhat in heat treat. Expect it.

If you are trying for the perfect grind pre-heat treat. STOP.

Just get your initial grinds close. More importantly get it straight on each side and consistent across the spine.

After heat treat - finish grinding will work on the perfection aspect.

DeMo
 
Let's think about this in stages. For the sake of argument, we'll say that a knife is done in three grits: 36, 60, 120. Anything after that is about getting the finish you want.

36 grit: Establish the initial flat bevel. Take it about halfway up the blade on both sides. There will be some waves. The plunge lines are short of where you want them. The edge is still thick and not perfect along the scribe lines. Good. Who cares.

60 grit: our mission is FLAT FLAT FLAT and get rid of any sign that you ever used a 36 grit belt. We go to 75% of our bevel height. We get the plunge lines even on both sides. Not perfect, just even. We get the bevels looking the same on both sides as viewed from the edge as well as the spine. There may still be some little bit of wave along the top of the bevel. Not much, but we aren't shooting for perfect.

120 grit: Now we're looking for perfect. Get your plunge lines perfect on both sides. This sets up us for how high the final bevel will be because setting the plunges evenly pretty much locks us in on that. Nice, cautious, even passes with almost no pressure, especially as we blend the tip.

I grind everything after heat treat, so when I am done with 120 grit, the edge is maybe .010

When I go to 220 to remove my 120 scratches the edge will be pretty much a zero-grind edge. The blade is done except for hand sanding. (or whatever additional things you do like rounding the spine, etc)
 
Last edited:
More importantly get it straight on each side and consistent across the spine.

Straight on each side, referring to the transition line between bevel and flat?

Not sure what you mean by "consistent across the spine"? consistent in relationship to the transition line?
 
I think Demo is saying getting both sides the same so that the stresses will equal out.

I grind everything after heat treat, so please remember that when you read my post. You definitely don't want to go to completion before heat treat. As Demo says, that's not just a waste of time but counterproductive because you may have to grind some warp out post heat treat.
 
Here is a tip that might help you. I use layout dye (blue dykem) on each side of the blade. It helps me see the lines better. Grinding truly is an educated feeling and not necessarily a sight picture. But, the dykem allows me to see better and adjust accordingly.

Personally, I'm old and I'm color blind. My shop is not the best lit place.

Blue Dykem helps me see the grind lines and that helps to make adjustments. For the most part, I just grind it off.

DeMo
 
Straight on each side, referring to the transition line between bevel and flat?

YES. Straight grind lines along the spine of the knife blank.



Not sure what you mean by "consistent across the spine"? consistent in relationship to the transition line?

I meant consistent with each side. Have the grind line on each side in the same position on the knife blank. If that is 1/2 inch up, 1/2 inch down, 1/4 inch up, 1/4 inch down. Wherever you choose to put it - keep it the same on each side of the knife blank.
 
Grinding is really a feel thing. When the knife blank is pressed against the platen, you cannot see where you are grinding. You have to feel your way along. for some, it takes a great deal of practice. Others pick it up fairly quickly.

Please remember, every knife maker grinds a little bit differently. John grinds all post heat treat. I preliminary grind pre heat treat. Neither of us is wrong. Just different.

Some grind edge up, some edge down. Some are right hand dominant, some left hand dominant. Again, none are wrong. Just different.

You will need to develop your own grinding style. What works for me is somewhat irrelevant to you if it will not work for you.

Practice, and develop what works for you. It is the best advice I can give to you.

DeMo
 
Back
Top