Uneven bevels only on longer blades

T

Tyler.t76

Joined
May 19, 2022
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70
I’m having trouble with one side of my grind every time I do my bevels on my longer knives (4.5” and up) I’ve never had this with my shorter knives and I’ve only recently taken up longer blades. I’ve tried different grips, stances, and pressure and seem to have the same result each time. So does anyone have any ideas what I could be doing wrong and could correct? I will post pictures below, thanks!
9T05vsz.jpg

7au2ARW.jpg

First picture is the problem, second is just the other side where I’m not having any issues.
 
T Tyler.t76 ,
Not trying to be a smartass or anything... Just grind more in that spot.

You don't have to grind the whole length of the blade, or keep the same amount of pressure the whole time. You can also put more pressure towards the spine in that area. There's not really a secret technique. Just grind more where you need metal removed.
 
That side really got away from you. Looking closely, the good side isn't perfect.
Starting from a flat profile, I suggest scribing the center line of the edge. Then lightly scribe just below where you want the bevel to reach, say parallel to the edge. I find it easier to grind accurately with a coarse grit, 36 or 50. Grind the edge on both sides at 45 degrees, not quite to the center line. Then very lightly, walk it up towards your scribe for the height you want. Try to be very straight and parallel at each step as you go. Touch the scribe with the coarse grit, then switch to say 120 and just wipe out the line.
 
Richard338 said:
That side really got away from you. Looking closely, the good side isn't perfect.
Starting from a flat profile, I suggest scribing the center line of the edge. Then lightly scribe just below where you want the bevel to reach, say parallel to the edge. I find it easier to grind accurately with a coarse grit, 36 or 50. Grind the edge on both sides at 45 degrees, not quite to the center line. Then very lightly, walk it up towards your scribe for the height you want. Try to be very straight and parallel at each step as you go. Touch the scribe with the coarse grit, then switch to say 120 and just wipe out the line.
Click to expand...
Appreciate the tips, and the better side looks a little wonky because I was getting frustrated and if I was a little wiser I would’ve walked away and took a break and not had to scrap the knife haha! Every knife I’ve done below 4” I’ve rarely had trouble with after I got the hang of it the first time, so I guess I’ll just have to mess up a few more times until I get it right on these longer ones!
 
A.McPherson said:
T Tyler.t76 ,
Not trying to be a smartass or anything... Just grind more in that spot.

You don't have to grind the whole length of the blade, or keep the same amount of pressure the whole time. You can also put more pressure towards the spine in that area. There's not really a secret technique. Just grind more where you need metal removed.
Click to expand...
I tried this a little, but realized a little late that it had gone a bit too far, I’ll either go ahead and try and salvage it by doing a full grind or throw it in the scrap pile as a reminder, thanks for the help!
 
I find for me making sure the belt is sharp helps
The minute I start to get these results I put on a new belt.
 
Kid Couteau said:
I find for me making sure the belt is sharp helps
The minute I start to get these results I put on a new belt.
Click to expand...
That could have something to do with it, my Norton blaze belts are about at their limit and I’ve been waiting to order some until I knew I needed some other things to save in shipping 😅
 
Tyler.t76 said:
How do you suggest doing the distal taper first? I’ve never tried that, thanks!
Click to expand...
I don't know where you are experience wise so I'll just start from one.
Distal taper which most knives have is the thinning of the blade from the front of the ricasso to the tip. Don't thin the ricasso itself.
Start by spraying both sides of the blade with layout blue, let it dry. It's best to use a grinding magnet when grinding distal taper. If you can, set the flat platen in a vertical position. Use a 60 to 80 grit belt to grind with. Place the grinding magnet on the ricasso or on the tang, depending on blade design. Grind at medium speed until you get used to doing this. Stand in front of your grinder with your elbows locked. Hold the magnet/blade, in both hands and lay the blade against the moving belt with just a slight amount of pressure towards the tip. You want to remove the steel from the tip of the blade back towards the front of the ricasso. After a few revolutions of the belt, take a look at the surface of the blade and see if you are making contact with the belt in the correct place on the blades surface. You can tell instantly if you are holding the blade in the correct orientation by looking at where the layout blue has been removed. The bluing should be removed from the tip back and the bluing line should be square across the blade; this way you will know if the metal is being removed evenly across the blades surface. Grind a little and then check the bluing line to make sure it is straight across the blades surface. Keep in mind, you are grinding at a very slight angle relative to the platen's surface. You want to end up with a flat surface from tip to the front of the ricasso and you want to be square across the blade surface, [from edge to spine] Complete one side before moving to the opposite side. Set the magnet in the same location as you did on the opposite side.
This is a skill well worth developing. It will help a great deal with your grind lines being even. Grinding without distal taper you are fighting to remove more metal as the belt moves forwards towards the tip. If you've ground the distal taper into the blade this does not happen and the same pressure can be applied from plunge line to tip. I suggest that you try doing this using some flat stock . No need to put a tip on it. You're just trying to get a feel for grinding at the correct angles and keeping the blade square.
I grind distal taper using a Bubble Jig. You set the BJ on the grinding magnet and you let the bubble just bump the black line inside the vile. This is about 1/2 degree. Doing it this way takes the guess work out of it. Quite a few smiths on here use this tool to grind distal taper.
You can call me on my 800 number if you have any questions about this technique.
Regards, Fred
 
Fred.Rowe said:
I don't know where you are experience wise so I'll just start from one.
Distal taper which most knives have is the thinning of the blade from the front of the ricasso to the tip. Don't thin the ricasso itself.
Start by spraying both sides of the blade with layout blue, let it dry. It's best to use a grinding magnet when grinding distal taper. If you can, set the flat platen in a vertical position. Use a 60 to 80 grit belt to grind with. Place the grinding magnet on the ricasso or on the tang, depending on blade design. Grind at medium speed until you get used to doing this. Stand in front of your grinder with your elbows locked. Hold the magnet/blade, in both hands and lay the blade against the moving belt with just a slight amount of pressure towards the tip. You want to remove the steel from the tip of the blade back towards the front of the ricasso. After a few revolutions of the belt, take a look at the surface of the blade and see if you are making contact with the belt in the correct place on the blades surface. You can tell instantly if you are holding the blade in the correct orientation by looking at where the layout blue has been removed. The bluing should be removed from the tip back and the bluing line should be square across the blade; this way you will know if the metal is being removed evenly across the blades surface. Grind a little and then check the bluing line to make sure it is straight across the blades surface. Keep in mind, you are grinding at a very slight angle relative to the platen's surface. You want to end up with a flat surface from tip to the front of the ricasso and you want to be square across the blade surface, [from edge to spine] Complete one side before moving to the opposite side. Set the magnet in the same location as you did on the opposite side.
This is a skill well worth developing. It will help a great deal with your grind lines being even. Grinding without distal taper you are fighting to remove more metal as the belt moves forwards towards the tip. If you've ground the distal taper into the blade this does not happen and the same pressure can be applied from plunge line to tip. I suggest that you try doing this using some flat stock . No need to put a tip on it. You're just trying to get a feel for grinding at the correct angles and keeping the blade square.
I grind distal taper using a Bubble Jig. You set the BJ on the grinding magnet and you let the bubble just bump the black line inside the vile. This is about 1/2 degree. Doing it this way takes the guess work out of it. Quite a few smiths on here use this tool to grind distal taper.
You can call me on my 800 number if you have any questions about this technique.
Regards, Fred
Click to expand...
That does make a lot of sense, never really crossed my mind how much I had to fight the tip when I grind my bevels, appreciate the explanation I’ll try it out tomorrow, thanks!
 
Marker or blue the blade before each pass.

Slow grinder speed

Fine grit belt like three or four hundred grit, or equivalent structured.

Blue it, make a pass, look at it, blue it, make a pass look at it; and so on.

It's hard switching sides.
You have to learn feel and feedback of what you're doing.

Practice what you're bad at, not the fun side you're good at.
 
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My answer does not exactly answer your question (based on images), but for a long time I was having a problem with bevels on two side not being identical in the area of the tip of the knife - on one side it would be the same height as on the rest of the knife, but on the other side as I got to the tip of the knife, it would get progressively smaller and smaller. Used to drive me nuts. Eventually I figured out the issue - on one side (good one), when I would get to the tip I would turn the knife so that the tip would be in contact with the belt and then drag it parallel to the belt. This gave me a nice uniform bevel. On the bad side I would also turn the tip to be in contact with the belt, but about half way through the belt I would pull the knife back, which resulted in a much smaller bevel. Took me a while to figure out, but once I realized the mechanics at play it all made sense. Since we have a dominant hand, we tend to do things differently on both sides, so instead of just doing it try to understand the mechanics involved and this would allow you to adjust the body movement/position.
 
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