What's the trick to achieving a nice, straight grind line?

freds bubble jig would be an exception since it helps you keep the same angle while you are freehand grinding.
 
When i was introduced to hollow grinding i was told not to "peek" at my progress, and some folks need a sharpened brass rod to "keep em from peekin", my elbows were pushed tight to my sides, my hands found a nice place together that could work with my wrists, my legs are shoulder width apart and my putting stroke came in to play once again!! Seriously i set up to and excute my hollows the same way i do when im on the green puttin out! The bottom line is practice, practice, practice!!!
 
As mentioned before, body position. I would also add grinder location; is it at a comfortable height and do you have to stretch over your dip bucket or dust collection system? And just because it hasn't been mentioned enough PRACTICE!

I really encourage grinding at a slow speed with known steel. I have seen recommendations to grind on mild steel; it does not grind the same as nice clean steel!

David Sharp
 
+1 for the bubble jig and practice. Be very aware of keeping even steady pressure as you move the blade and don't just start at one and and pull to the other or your plunge will always lag behind the rest significantly. Start a bit out and slide back to your plunge line then reverse the length of the blade. This takes some practice since that one section will progress faster until you get the hang of how fast to move and when.

Sharp belts help tremendously. With dull belts it's hard to work slowly because of how much heat they generate, you have to stop and cool the blade too soon. A nice sharp fresh belt lets you get good results without heavy pressure and without lots of heat, freeing you to focus on the fundamentals.

I'm still very much a newbie here and have trouble getting my bevels and plunges to match side to side, but by following the advice I've gotten here (and lots of practice) I'm very good at keeping them nice and even individually. heheh, it's getting them to line up together that I have issues with. I always goof something on one and then have to fix it, which requires going back to the other side to make them match again.... The remedy is simply more practice.
 
Something that may help is to scribe 4 lines on your blade(on each side) about 3/16" apart and practice grinding to each line.
This way you get 4 blades worth of practice out of 1 piece of steel and it should push you along faster in your practice(less to grind each time).
This will also help you if you have to grind a blade halfway up or even less.
Thanks,
Del
 
Mooseyard said:
What does everyone think of the bubble jig. Good idea for a beginner or no?
Click to expand...

I make them and have used one for almost ten years so I have an opinion on them.

They are not magic; the bubble is a reference; but the reference is the same each and ever time and identical on both sides of the blade. When a person is grinding with nothing but the blade in their hand; what reference do they use? They are watching the gap where the edge contacts the belt and they are making an educated guess at the angle. With the bubble set at a desired angle and attached to the blade or bevel clamp you center the bubble and then grind. There is no guessing to it. You can still screw up the grind using the bubble, but you get almost instant confidence by knowing the angle of approach is just like the last pass. Its a great teaching aid. I talk to people who have been using it for years and they say they set one angle on the jig and use that to grind the entire blade. Edge development all the way through finished bevels. They just cheat the bubble between the lines move it one way for the edge and then tilting it back a bit to move the grind line up the bevel.
This is not a sales pitch, they sell themselves; I am just telling you how it works.

Regards, Fred
 
Remyrw said:
+1 for the bubble jig and practice. Be very aware of keeping even steady pressure as you move the blade and don't just start at one and and pull to the other or your plunge will always lag behind the rest significantly. Start a bit out and slide back to your plunge line then reverse the length of the blade. This takes some practice since that one section will progress faster until you get the hang of how fast to move and when.

Sharp belts help tremendously. With dull belts it's hard to work slowly because of how much heat they generate, you have to stop and cool the blade too soon. A nice sharp fresh belt lets you get good results without heavy pressure and without lots of heat, freeing you to focus on the fundamentals.

I'm still very much a newbie here and have trouble getting my bevels and plunges to match side to side, but by following the advice I've gotten here (and lots of practice) I'm very good at keeping them nice and even individually. heheh, it's getting them to line up together that I have issues with. I always goof something on one and then have to fix it, which requires going back to the other side to make them match again.... The remedy is simply more practice.
Click to expand...
Thanks for posting this. This thing is not a sled jig and it is not magic. As you say it takes practice; but the practice is done with a lot more confidence because you are not guessing.
Fred
 
I mostly flat grind. One thing that has helped me to progress is to be able to feel the bevel part of the blade that is on the platen and also where that bevel is on the belt. Sometimes you will use the side of the belt to really grind material fast and other times you are using the full width of the belt for more controll. You get to the point that you know what part of the bevel you are grinding (top to thin the edge or back to climb the bevel up the spine) and only look at the bevel between passes to confirm that you were indeed grinding the part you wanted. However all this said, I ground a great bevel on a 10+ inch long 2 inch wide damascus chef knife yesterday on my weak side and totally screwed up the grind on my strong side ten minutes later..........so practice and determination help tremendously.
 
Use a jig. I use a piece of 2" angle steel and clamp the blade to it. Simple, and you can get straight grind lines with ease.
 
Fred.Rowe said:
Thanks for posting this. This thing is not a sled jig and it is not magic. As you say it takes practice; but the practice is done with a lot more confidence because you are not guessing.
Fred
Click to expand...
It certainly helps me a lot. As you say, it's a confidence and "cheat" for getting a consistent approach. I can pick an angle for the thickness of the steel, height of grind, and single or double bevel style and use the bubble to know I'm at the right angle as I work. That doesn't mean I can't mess up, but it DOES give me feedback that I'm messing up. If that bubble starts to stray from center once I've worked my way to the chosen angle (I set it and manually work the bevel upward to that angle rather than change the jig through the steps) then I know I somehow pushed the blade out of position far enough to be off kilter. I can then see WHERE on the blade it is and see my progress back to straight more easily.

It's not magic, it's not doing the work for you, it's just making it easier to be consistent and see what you're doing. Buying my bubble jig was probably the best material investment I've made in knife making. My membership here was the best non material investment.
 
[video=youtube;_RZT5mpTSHQ]http://www.youtube.com/watch?v=_RZT5mpTSHQ&feature=mh_lolz&list=FLuC36CLjx7vg[/video]
 
^ I'm sure the technique shown in that video will work, but as I've said before... by the time you screw around and build that monster, you could have ground or filed two blades freehand and learned a lot more about what you're actually trying to accomplish. Just my opinion, of course.
 
jaymeister99 said:
Use a jig. I use a piece of 2" angle steel and clamp the blade to it. Simple, and you can get straight grind lines with ease.
Click to expand...

I do the same, but this method has it's own issues. A few of which are below:
1. If the tool rest is not clean, it can cause issues in the draw of the blade against the platen.
2. If their is extra material in the grind near the ricasso, as you push the blade into the platen, it will kick out the ricasso side. Thus, you get a gouge in the middle of the primary grind.
3. Watch the tip, as you can focus on the grinding the front of the knife and burn the tip off if your concentrating only on the grind line.
 
Use layout dye. Keep an eye on high spots in the grind and level them out by slowing down on the high spot. Do this a few times and then blend the grind line together with a few quick passes. Repeat until the entire bevel is ground. That's how I do it.

Take your time. If you are using a machine with a fixed fast RPM, use light pressure. It's take more time but you'll have more control.

As others have said, find a steady and comfortable method/position and repeat.

Also, make sure you have good lighting.
 
I suggest checking out Tim Hancock's video. His method is very systematic and straight-forward to pick up. The use of a work rest and push stick made a huuuge difference for me.

[video=youtube;sdQmuDFuSG4]https://www.youtube.com/watch?v=sdQmuDFuSG4[/video]
 
It is easier than you think...really, but it is not like offering the blade to the belt at a certain angle and think she'll do the grind...the belt knows nothing how to make a knife!
It is the other way around! It is you that decide where to cut and move accordingly. The best thing is to take a scrap piece and relax, as soon you discover how easy is to walk the grind EXACTLY where you want, putting pressure where you want, you can start perfectioning bevels on real knives.
My beginner mistake was to be too focused in keeping a steady angle, thus just "enlarging" the starting bevel with all the errors it had. The problem was that it really requires some pressure modification to steer the grind line and make it flow.
I find fresh belts help, and also a rest table is useful to resist the belt drag, even just to steady your hands onto if not the blade itself.
Remember to use grinding belts to grind and finishing belts for just "cosmetics" surface touch ups and minor blending.
For flat grinds a disk grinder is great to even things up in the last steps, but a granite+paper is enough to get rid of any residual uneveness.
 
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