Bevel grinding development advice

[ERRN]

Do you think it will cause more problems if I jump from ten degrees to 3 or 4 since my edge will be so far off the belt? Or will it bo ok since I am mostly watching the bubble and the squareness of the blade to the platen? I'm not watching the edge as closely.

 

[kuraki]

Well that's the thing about the bubble. It only tells you one angle and you're working in three. If you can get used to watching the bubble and the blade without going crosseyed, you're good to go. Keeping the edge against the belt just helps me because you can see many things by that, grinding too much or too little in one spot, digging the blade into the platen edge.

From what I've read about how other people grind I'm in the minority and most seem to do it the way you're talking about.

 

[comet_sharp]

One thing that helped me the most is watching the sparks. I keel my sparks centered with the belt so I know my pressure is even against the platen. If you're doing a pass and only the left side of your platen is throwing sparks then put more pressure on the platen with your right hand, etc.

 

[john april]

eventually you will learn to lock your wrist and you wont have to look at the bubble so much because you can hold the angle. at 10 degrees, you will develop a flat, you will learn to feel when this is flat on the platen with your hands, then walk or tip that flat toward the spine.

 

[Ghostman3]

Well that's the thing about the bubble. It only tells you one angle and you're working in three. If you can get used to watching the bubble and the blade without going crosseyed, you're good to go. Keeping the edge against the belt just helps me because you can see many things by that, grinding too much or too little in one spot, digging the blade into the platen edge.

From what I've read about how other people grind I'm in the minority and most seem to do it the way you're talking about.

I do it this way as well. When I grind I grind the bevel that suppose to be there. Have only free hand grinder and never had any problem doing it like this. Actually surprise myself how accurate I can be.


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[Pittknife]

I went through about 80 practice blades over a year to learn how to free hand hollow grind. I make flippers and one of my goals was to be able to grab a folder blade without any assistance and grind the bevels. Free hand grinding is an art and very hard to teach because what works for one person won't work for another.

People have different physical limitations and cognitive motor skills so what I found is the only way to learn how to free hand, especially a hollow grind is to ruin blades...

I picked up flat grinding pretty fast but the hollow free hand was so difficult that I almost gave up. But like with everything else if you put in the time you get good at it. I had another maker in my shop and was teaching him how to hollow grind and after he messed up the first knife he told me I made it look so easy. I took out my first blade I ground and show d him how bad it was and said the same thing I say to everyone, just practice you will get better.

here are some things I do now vs when I first started that really helped me:
- I don't chase even lines until I reach 220 grit, meaning I leave enough room to get out the scratches from rough grinding
- grind at a slower speed, on my vfd it's about 30-40%.
- don't rush and try to move up the grind line.
- establish my hollow...
- don't panic
- when I first make contact it's light, then apply pressure


Here are some of my recent grinds:

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[ERRN]

That blade is beautiful Mike. Whole different level!

Ok, so here is the first blade with the bubble jig. I had trouble judging which angle would leave my bevel at the height I wanted it, and I ended up a bit higher than I planned, but I figure I'll get better at judging that as I go. I got pretty good at correcting the line as I chased it up, but think I hurried when I went to higher grits, and tilted it too vertical a couple times. One side has a slight arc, and the other sweeps up at the top of the plunge line. Will these correct a bit with sanding the flats, or do you think I run too much of a risk of washing out the bevel line messing with that?

 

[rybobales]

What you'll find the difference in say blades 10-20 and 20+ is your ability to correct mistakes and know what you did wrong right when it happens - something i'm now starting to comprehend.

On your original question "would you recommend just grinding a bunch out and working on that, or would you grind one and work the whole knife to completion one at a time?"

Do what makes you feel comfortable. One to completion can be really rewarding and offer you a "pure" feel. It's also easier than juggling 10 blades at different stages.

I tend to have a lot going at different stages. This makes so if i get limited time in my shop i always work on something. But i've had to change direction many times to get one done - so if anything work that skill first.

 

[E.Carlson]

I would just blend the little bit of flat into the bevel while hand sanding. You won't even be able to tell it's there. I leave a flat bit just like that on my flat grinds so I have a flat part to stamp my name.

 

[Lyon]

What I did to learn freehand grinding was to go down to the local machine shop/fab shop and buy a bunch of steel. They have lengths of 20 foot steel in most of the common thicknesses and it varies in width. They sell it by the pound. For 20 bucks you can get yourself quite a bit of practice material.

I started out on the grizzley 2X72 as well. If you get decent on that you will have a significant quality increase on a variable speed grinder! As mentioned previously in the thread, variable speed REALLY helps.

I also found that keeping a sharp belt helps me maintain an even grind and improves the feel I have on the grinder.

 

[Daniel Fairly Knives]

Learning to bring the knife to the belt is the key to me, look at the edge at make sure it matches the angle you are at. Move in with confidence but not too fast or slow. This helps you learn what angle the knife is at then when you do the other side it will match more evenly.

If a grind is too low in one spot put some more pressure in that spot. Use sharp belts that cut cleanly.

 

[Fred.Rowe]

One thing that helped me the most is watching the sparks. I keel my sparks centered with the belt so I know my pressure is even against the platen. If you're doing a pass and only the left side of your platen is throwing sparks then put more pressure on the platen with your right hand, etc.

:thumbup:

 

[Fred.Rowe]

Do you think it will cause more problems if I jump from ten degrees to 3 or 4 since my edge will be so far off the belt? Or will it bo ok since I am mostly watching the bubble and the squareness of the blade to the platen? I'm not watching the edge as closely.

It is just a matter of experience in selecting a grinding angle. Ten degrees to develop the edge is arbitrary. You can start at 5 degrees, which I do a great deal. Many blades can be ground start to finish using the 5 degree setting. Develop the edge at 5 degrees from plunge to tip. The edge should be the same thickness the entire length. If the blade is going to be ground with distal taper, do so before you start the bevels and you will save yourself a great deal of work.
When you have the edge at just about heat treat thickness try letting the bubble "bump" up against the black line in the bubble vial. This adds 1/2 a degree.

Follow this link to see the other bubble positions: https://get.google.com/albumarchive.../AF1QipMBibD4spNwRa4UZcy0b5VOdKpeR9I2rZ1-gyyR

Do this instead of actually changing angles by resetting the bubble position. As stated above. I grind many average blades in this manner. Set the bubble @ 5 degrees and float the bubble to increase the grind angle.

With a little experience you will be able to look at a blade and know the angle to use. As stated, it is just a matter of a little experience. The suggestion about watching the spark pattern is dead on. You can watch the bubble position and the spark pattern at the same time. You will get exact bevels with this technique.

Your original question:about doing it wrong by going from this angle to that. NO, there is no wrong in this.

Let me make this point. If I am grinding a large bowie or fighter, 2 1/2 high by 10 inches long: I will start at the 5 degree setting and walk my way down through the angles. A knife this size will end up at 2 1/2 degree bevels if the steel is 1/4 inch thick. The reason I step the angle down 5-4-3 1/2- 3- 2 1/2 is grinding on each of these planes will remove the steel faster because each drop in degrees will have you grinding on the next "high spot" of the bevel. Instead of hogging the entire bevel, you do it in sections. Its faster, I've ground 1000 blades with a Bubble Jig. As I stated earlier, I can grind "free Hand" I can grind faster and much more accurate with a BJ.

You have my 800 number, give me a call if you wish to further this conversation. Fred

 

[TG custom blades]

This is a great thread and perfecting timing for me
As I have always used a very basic jig for my grinds. Just earlier tonight I started to try some free hand and it was not a pretty sight. But after reading this I think I am going to have to invest a little money into A Bubble jig. That is exactly what I have been looking for. I know I Did not start this thread but thanks for the info.

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