New Knife Maker, Questions about Bevels

JRB Blades

JRB Blades

Knifemaker / Craftsman / Service Provider
Joined
Jul 22, 2013
Messages
266
New knife maker here. Starting out doing some stock removal to get my skills down. Then I hope to move into forging my own blades.


Since I’m new, I’m not very good at grinding. Since I have no experience at all, I got 2 different types of jigs and for a reference I free handed. I got Fred’s bubble jig, a Creativeman beveling jig/file guide, and then obviously free hand grinding. I went to Home Depot and got some mild steel and cut out a few knife blanks. To keep the results consistent I made the same style knife for all three.



The first two pictures are using the bubble jig. I started out with the 10° wedge to knock my edges off and set the bevel profile. Then I moved to the 5° block. That is where I stopped for that particular jig. I got really good results on one side, and some not so good results on the other side.

vZb4XK2.jpg


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The second set of pictures are using the Creativeman file guide and jig. I started out at a very sharp angle to knock the edges off and then progressively lowered the angle until my bevels where I wanted them. With this particular set up, I did find that I grind it over my center line very easily.


DywRFh3.jpg


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The last set of pictures are my attempt at free handing. I was very happy with the one side of the blade. Obviously pulling with my right hand is my strong side. Ignore the grind marks up near the top, I flattened the steel on my Platten and that’s where some of the grind marks near the spine of the blade are coming from.

jsuzTlI.jpg


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All in all, I got good results on one side doing freehand and the bubble jig. The Creativeman file guide and jig gave me semi-consistent results from side to side, there was just a little problem of grinding over my center line. This is obviously user error. I think I stayed at the same angle for too many passes as opposed to decreasing my angle when I should have.



Take away message, I definitely need to work on my left hand pull side with the bubble and and free handing. And I need to work on reducing my angles at the proper time while using the Creativeman file guide and jig together.

What belt speed are you guys running when grinding primary bevels. I am using a 36grit ceramic belt. I have heard that most people are at 3-5K fpm?
 
That does not look bad at all. Go as fast as your grinder will go, or as fast as you dare.

Instead of pulling with your hand, you can try locking your elbows to the sides of your body and moving your whole body. Might give you more control. It takes a little practice, but you are off to a good start. I never had good luck with a jig that holds the blade and ruined a few blades before going freehand. I'd use knife steel for practice, it does not cost all that much in the global scheme of things.
 
Agreed. I have 8 more blanks that I cut out of that batch of mild steel from HD. I figure I'm gonna do most of them freehand and really focus on that for now. I think I have a good handle on what to do, just need to practice doing it. Definitely keeping elbows locked into my sides and pulling with my body and not my hands. I have been knocking the corners off at around 45 degrees and then trying to knock that angle between the flat of the blade and the 45 that I just ground. Once I get that, it's a bit easier to feather the blade to the platten on that new bevel. My question is, to move the grind line down, do I apply pressure toward the spine side of the blade with the support hand (left hand if holding the tang in my right hand) or do I rotate the handle to increase the pressure on the spine side? By rotating the handle, I am referring to increasing throttle if you've ever ridden a motorcycle (rotating the spine towards the platten with the hand that is holding the tang).
 
My grinder runs about 6600 sfpm at wide open throttle. I have been running it at about 7/10 on the VFD. Considering turning it down to about 3000-3300 sfpm to see if I can get more control that way.
 
barlowchiro said:
Agreed. I have 8 more blanks that I cut out of that batch of mild steel from HD. I figure I'm gonna do most of them freehand and really focus on that for now. I think I have a good handle on what to do, just need to practice doing it. Definitely keeping elbows locked into my sides and pulling with my body and not my hands. I have been knocking the corners off at around 45 degrees and then trying to knock that angle between the flat of the blade and the 45 that I just ground. Once I get that, it's a bit easier to feather the blade to the platten on that new bevel. My question is, to move the grind line down, do I apply pressure toward the spine side of the blade with the support hand (left hand if holding the tang in my right hand) or do I rotate the handle to increase the pressure on the spine side? By rotating the handle, I am referring to increasing throttle if you've ever ridden a motorcycle (rotating the spine towards the platten with the hand that is holding the tang).
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I get a bit more control running slower. I like fresh 36 grit belts. You mentioned twisting or torquing the tang to walk up the grind. I find it useful to do a couple light passes doing that and then look closely at the result. For example if you are trying to get the plunge to go higher more quickly. You will soon get a feel for how to adjust where you are taking off material. Sometimes I will make a long pass, but use more pressure on one area. There is no substitute for just grinding a bunch of blades.
 
In order to move the grind line towards the spine, you are saying to twist or torque the tang? I have heard that the hand that holds the tang should be strong to hold the angle, but neutral. The off hand applies pressure lower on the blade towards the spine in order to walk the bevel towards the spine. Which is it? Is it a combination of both?
 
Disclaimer: I have only picked up what I do by trial and error.
When I did two Bowies recently, I would say that I was holding them by the tip and the tang and as I move onto the tip I move my hand a little and control more by the tang.
Going the other way and reaching the plunge, trying to walk up the grind, I would agree that perhaps I was holding it flat, but applying a bit of twisting pressure to move the grind that way.
You will get the feel for it. I also find that the grind feels different for different blade styles. I did some tantos recently with no plunges and I never felt like I was twisting them.
 
Use HD paint sticks to practice on, it is cheaper and easier to learn how to control the grind.

DYE chem the blade, use a dial caliper to mark how high you want the grind to go on both sides. Use that line to see how the grind is progressing.

Keep in mind you do not have to do the full length in a pass. Just go a little at a time and check what was done. Do this 20-30 times each side moving the grind line up a wee bit with each pass until you get to the line.

Hold the blade, stand and move the exact same way on both sides. This will help eliminate variables when grinding.

Remember you are grinding a triangle. If you have an edge line and a scribed grind line just move the grind up from the tip a little bit each pass. Stop several times as you grind a bit, see where it is at and move on and stop again.

Do the grind little by little and do not attempt to do it in a full sweep from plunge to tip when you are starting off.
 
I learned that you don't have to grind the whole length of the blade every pass. I have been using the bubble jig. If I was sitting with your first blade I would clean up the side that didn't turn out so well by working the tip end a bit to get that wobble out, and then work the part near the plunge line to get the grind looking more uniform and even sized. Then I would make a light pass or two to make the entire grind on that side look even. Then I would go back to the first side and work it up until it matched the other side I fixed.
TBH I have no clue if my approach is the right one....it's just the method that has sort of worked for me.

Also, you can lighten up a bit when you get close and take less material off in your final passes. I also have moved to 80 grit when I am close so I can have a bit more control.
Those are pretty reasonable for first tries. Especially the ones you did with the creativeman.
Nice job.
 
I've had really good results using the push stick technique. My grinds are wayyyy cleaner than with a jig or free hand. I find it way simpler to direct where I want the pressure and place to cut
 
So when you guys are moving the grind line up towards the spine. Are you using pressure with your off hand (non tang hand) or are you rotating the tang to put more pressure on the spine. I have heard both ways. I'm sure people use one or both of these methods. Also, all the videos and tutorials I have read talk about making one smooth complete pass from plunge line to tip without stopping. I know practice and actually grinding bevels is the key to getting better, just trying to shorten the learning curve as much as I can.
 
Nick-D said:
I've had really good results using the push stick technique. My grinds are wayyyy cleaner than with a jig or free hand. I find it way simpler to direct where I want the pressure and place to cut
Click to expand...

Are you keeping the push stick stationary or is it moving with the blade as you pull it across the platten? Where are you directing your pressure with the stick? Towards the spine side of the blade? I'd be interested in learning more about this method as well.
 
barlowchiro said:
Are you using pressure with your off hand (non tang hand) or are you rotating the tang to put more pressure on the spine.
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I try to have one hand focus only on pulling the blade across the sander (disc or belt) at whatever speed I need (pausing where needed), and the other hand uses as many finger tips as necessary to keep the blade flat against the platen and to add pressure on the bevel where it needs to be in order to remove material.

I haven't had much success with push sticks, I think mainly because it only lets you put pressure at one point of the blade, and too easy to rock the blade, causing the edge of the platen to dig into the blade.
 
weo said:
I try to have one hand focus only on pulling the blade across the sander (disc or belt) at whatever speed I need (pausing where needed), and the other hand uses as many finger tips as necessary to keep the blade flat against the platen and to add pressure on the bevel where it needs to be in order to remove material.

I haven't had much success with push sticks, I think mainly because it only lets you put pressure at one point of the blade, and too easy to rock the blade, causing the edge of the platen to dig into the blade.
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Ditto to this approach. This allows you to “feel” when you are flat on the platen. Then tweak The grind upwards or downwards, depending on needs at that spot

(caveat - I’m still not satisfied with my ability to produce nice even grind lines ... but then again I do almost exclusively full flat grinds .. and have so far “played” with keeping an even grind line as I move it towards the spine. When you get to a shallow angle, maintaining a clean grind line gets REALLY difficult...
 
Nick-D said:
I've had really good results using the push stick technique. My grinds are wayyyy cleaner than with a jig or free hand. I find it way simpler to direct where I want the pressure and place to cut
Click to expand...
Push stick is my favorite as well. I grind a rough angle on the stick so it sets the grind. Once I have one side set I grind double the angle on the stick and set the other side. I go freehand once I get close.
 
barlowchiro said:
Are you keeping the push stick stationary or is it moving with the blade as you pull it across the platten? Where are you directing your pressure with the stick? Towards the spine side of the blade? I'd be interested in learning more about this method as well.
Click to expand...

Full disclaimer, I'm a new maker so take this with a pinch of salt.

I position the stick where I want to remove material, the stick stays in the middle of the platen but I will move it up or down to follow the line of the blade as I draw it across.

Just like freehand grinding I start at the edge and walk the grind down to the spine. Positioning the stick where material need to be removed. I find It much easier to feather grinds in this way and end up with way less hand sanding than with my freehand grinds.

I works great for grinding in distal taper etc as well
 
I have a cheap little 2 x 42 I’m learning to grind with. I’m finding that even with a jig I have a long way to go before I get everything perfect. This is the first knife I’ve done that I didn’t feel like I had to keep going to a full flat or reprofile it into something else. The other side isn’t as good but not bad especially for my fourth knife ever. I’m getting better. Doing it freehand seems crazy hard to me. It’s definitely a skill I admire. Hmm. I can’t seem to post a photo
 
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not a bad start at all. you can still work on the bubble jig blank some more, maybe try 4 or 3.5 degrees to bring the grind up higher toward the spine, which will erase the uneven line. the uneven line happened when you changed your wrist angle, and the blade tipped too much. if you notice mistakes happening all of the sudden, slow the grinder down.
 
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