Progressive blade grinding or whats your angle.

[Fred.Rowe]

This thread was originally posted in 2009. If you have not seen it previously it contains some good food for thought.
Progressive grinding assures that as you grind up the blade the abrasive will make contact with the peak left by the last grinding angle. The steel is removed faster each time the angle of approach changes.



I used a 4 inch by 2 1/4inch by 5/16 inch section of planer blade for this demonstration.
The first picture shows the blade section, end on, before it was ground.

The second and third pics shows the grind on the left side of the blade using an angle of approach of 10 degrees.

The forth picture shows the results of switching to a 5 degree angle of approach. The grind moves up the blade and moves to intersect the edge that was ground at ten degrees.

This next picture shows the grind at 4 degrees angle of approach, the grind moves up the blade and moves to intersect the edge.

I jumped from a 4 degree angle to an angle of 2 1/2 degrees, relative to the belt surface, to show the amount of grind line change caused by changing the angle of approach by 1 1/2 degrees.

The last picture shows the grind at the 2 1/2 degree grinding angle.
As you can see the grind has gone completely across the 21/4 inch blade section.

The straight edge shows the ground side to be perfectly flat across the ground bevel.

When you grind blades by degrees, two things will happen, one is the grind goes faster because you are grinding across the high points left by the previous angle of approach. The second is you will end up with a perfectly flat bevel.

So whether you want a flat scandi grind blade, ground at 12 degrees or a wide chopper, three inches across, ground @ 2 degrees we are all looking for the same results, flat even bevels.
If you have questions send me a pm, happy to answer any questions you might have.



Happy grinding, Fred

 

[lonepine]

Is it possible to do this without a carefully calibrated grinder and blade holding jig? I.e. hand held?

- LonePine
Alias Paul Meske

 

[Fred.Rowe]

Hi Paul,

The grinding guide I use is about as free hand as it gets. Most any grinder will do.
Humans don't have a built in angle guide that indicates the different angles they are using while grinding.

Might I ask a question relative to your question? What is the goal people are trying to achieve when they go to making a knife? They want to make the best knife they can make correct?
I have worked at many crafts and trades in my life; surveyor, carpenter, welder bladesmith. In each of these the goal is to produce the best results you can. If I turned in a survey with a high closure rate; I was not ask if I did it by pacing alone. If I built a beautiful curved stairway; no one asked if I did it with a hand held saw. The same goes for doing good welding or any other craft or trade.
When I started making knives a dozen years ago the goal was to make beautiful functional knives; but for some strange reason people wanted to know if the beautiful knives I was making were made without any guide, advanced machinery or other contrivance.
I had never been asked this in carpentry, surveying or welding; why was I being asked this when making a knife? After all these yeas I still don't understand. I thought the goal was to do great work.

It always bothers me when I hear someone new to knifemaking ask a long time maker how to learn to grind nice blades; just practice practice practice until you get it. How long is that? Just keep practicing.

When I am asked, I respond " you can learn how to grind nice blades in a weekend" After that you can get on with making knives. I believe thats the idea, making nice knives.

Happy grinding, Fred

 

[rwn2000]

I have worked at many crafts and trades in my life; surveyor, carpenter, welder bladesmith. In each of these the goal is to produce the best results you can. If I turned in a survey with a high closure rate; I was not ask if I did it by pacing alone. If I built a beautiful curved stairway; no one asked if I did it with a hand held saw. The same goes for doing good welding or any other craft or trade.

Happy grinding, Fred

Fred, I'm a surveyor and civil engineer and beginning knifemaker (been at it about 1 1/2 years). Do you think your background in surveying and understanding angles, trig etc helped with developing your Bubble Jig? I know when i started I tried figuring what angle to grind at if I wanted to take 0.07" of the edge of the flat stock and come up the blade, say 0.75" but it really didn't work with the crappy sander.grinder I was using at the time.

randy

 

[Fred.Rowe]

Fred, I'm a surveyor and civil engineer and beginning knifemaker (been at it about 1 1/2 years). Do you think your background in surveying and understanding angles, trig etc helped with developing your Bubble Jig? I know when i started I tried figuring what angle to grind at if I wanted to take 0.07" of the edge of the flat stock and come up the blade, say 0.75" but it really didn't work with the crappy sander.grinder I was using at the time.

randy

Randy,

Great question.:thumbup: The years of calculating, we did it with paper and pencil in those days, running base line control for freeways and the like; followed by 30 years building everything under the sun, working as a carpenter; the Bubble Jig was a natural solution to my inability to grind nice blades. As with you; with my background grinding nice blades seemed like it should have come quite easily. Of course it didn't.

My mind is an analog system; not like today's younger people who think digitally.
When I took the time to go over the problem I had with grinding; my thoughts about solutions always presented themselves in the form of line, level, curves and spirals.
Just as your knife designs are rooted in in the work you have done through your life; so do the solutions to many of the challenges encountered in knife making.
People are tool makers, thats why we have survived where others have faded from the earth.
I love making knives; but I love problem solving even more. Thats why I go to the shop every day.

Thank you for your post, Fred

 

[james terrio]

Is it possible to do this without a carefully calibrated grinder and blade holding jig? I.e. hand held?

Yes. Even by "calibrated eyeball", following the same basic procedure will result in less heat build-up, less belt fouling, and faster results, as compared to simply holding your bar at the desired finish angle and grinding along the whole plane. It works just as well for setting full-convex bevels as it does for full-flats; you just blend the "facets" together for a smooth curve instead of coming all the way to the edge and making your final couple passes flat. You're "nibbling away" less steel in each pass, easing the contour or bevel down to what you want instead of trying to tear it all off at once. Sometimes "slower" is actually faster and more efficient.

This is coming from a guy who barely got a C in beginning algebra, so take heart

I'm getting fairly decent at keeping angles consistant by eye, but I threw away a LOT of KSO's along the way. If I were starting from scratch I'd seriously look into getting a bubble jig. In fact, it's on my Christmas list regardless!

 

[lonepine]

Hi Paul,

The grinding guide I use is about as free hand as it gets. Most any grinder will do.
Humans don't have a built in angle guide that indicates the different angles they are using while grinding.

Might I ask a question relative to your question? What is the goal people are trying to achieve when they go to making a knife? They want to make the best knife they can make correct?
I have worked at many crafts and trades in my life; surveyor, carpenter, welder bladesmith. In each of these the goal is to produce the best results you can. If I turned in a survey with a high closure rate; I was not ask if I did it by pacing alone. If I built a beautiful curved stairway; no one asked if I did it with a hand held saw. The same goes for doing good welding or any other craft or trade.
When I started making knives a dozen years ago the goal was to make beautiful functional knives; but for some strange reason people wanted to know if the beautiful knives I was making were made without any guide, advanced machinery or other contrivance.
I had never been asked this in carpentry, surveying or welding; why was I being asked this when making a knife? After all these yeas I still don't understand. I thought the goal was to do great work.

It always bothers me when I hear someone new to knifemaking ask a long time maker how to learn to grind nice blades; just practice practice practice until you get it. How long is that? Just keep practicing.

When I am asked, I respond " you can learn how to grind nice blades in a weekend" After that you can get on with making knives. I believe thats the idea, making nice knives.

Happy grinding, Fred

Fred, You misunderstand me though I can see how you would from the question I asked. I don't own a machine shop with CNC (or even non-CNC) tools, grinders, mills, lathes, etc., nor the knowledge skills and abilities to use them even if they magically appeared in my garage. Rather, I have a mundane 2X42 grinder with which I make mediocre knives for fun. (Remember the part about lacking knowledge skills and abilities? It applies to my grinder too) I don't strive for mediocrity, that's just my skill level. I see some FANTASTIC knives made with the same equipment I have and I know that there are quite a few people with better motor skills than I have. In my own uncouth manner I was wondering if progressive blade grinding to this degree of accuracy is possible to do by hand. If this is only attainable with high end equipment that's fine too, maybe even better because then I don't have to feel bad about not having the fine touch, feel, and dexterity that everybody else on this forum has (Or so it seems like to me some times).

I'm having troubles grinding blades and was looking for anything that would help me and wasn't sure if this was usable or not. Thanks for your patience and kind reply. I appreciate it.

Paul Meske, Wisconsin
Alias LonePine

 

[Fred.Rowe]

Fred, You misunderstand me though I can see how you would from the question I asked. I don't own a machine shop with CNC (or even non-CNC) tools, grinders, mills, lathes, etc., nor the knowledge skills and abilities to use them even if they magically appeared in my garage. Rather, I have a mundane 2X42 grinder with which I make mediocre knives for fun. (Remember the part about lacking knowledge skills and abilities? I applies to my grinder too) I don't strive for mediocrity, that's just my skill level. I see some FANTASTIC knives made with the same equipment I have and I know that there are quite a few people with better motor skills than I have. In my own uncouth manner I was wondering if progressive blade grinding to this degree of accuracy is possible to do by hand. If this is only attainable with high end equipment that's fine too, maybe even better because then I don't have to feel bad about not having the fine touch, feel, and dexterity that everybody else on this forum has (Or so it seems like to me some times).

I'm having troubles grinding blades and was looking for anything that would help me and wasn't sure if this was usable or not. Thanks for your patience and kind reply. I appreciate it.

Paul Meske, Wisconsin
Alias LonePine

Paul,

I am interested in how makers in the distant past produced works of art, with little but their hands and a few basic tools. Its obvious when you look at what they accomplished it does not require modern machinery to make beautiful and useful edged tools.
But even before modern machinery people who worked smarter instead of harder, were the most productive and produced the finest blades. The same thing applies today; work smarter not harder, that was the point
I was trying to make.
No one I know was great at anything when they started out. It takes time and "practice" to be accomplished. I gave away the first fifty knives I made. The 50th was much better than the first.
The jig I make and it is a free hand device will do more to advance your skills than any single item in your knife shop.


This post is not about selling you a jig. I have little enough time to make knives as it is. Its meant to inspire you to shoot for the top; no matter what equipment you have.

Regards, Fred

 

[lonepine]

You mean this is possible with a bubble jig?!?!?!?!?!?

- Paul Meske

 

[jonnymac44]

The jig I make and it is a free hand device will do more to advance your skills than any single item in your knife shop.
Regards, Fred

I'm starting to think that fred might be right. I spent some time learning to grind and was having a moderate level of success. I happened upon the bubble jig and thought I'd give it a try. Very quickly my lines started to get straighter, quicker! It's not that I couldn't grind before, but the jig takes some guess work out of the process and saves you time. I could grind my bevels pretty clean without it, but only after taking a fair amount of time to straighten and clean things up. With the jig I have less mistakes to fix.

I do like that it is still me doing the grinding. The bubble tells me where to hold the blade, but I'm the one holding it. Without my steady hand and concentration the jig is worthless. I'm not saying I'm in any way an advanced grinder or anything, just pointing out that the jig is not a miracle worker. It needs you to do your part to be successful. I'm enjoying using it in my shop right now and it is saving me lots of time:thumbup:

 

[Fred.Rowe]

Yes. Even by "calibrated eyeball", following the same basic procedure will result in less heat build-up, less belt fouling, and faster results, as compared to simply holding your bar at the desired finish angle and grinding along the whole plane. It works just as well for setting full-convex bevels as it does for full-flats; you just blend the "facets" together for a smooth curve instead of coming all the way to the edge and making your final couple passes flat. You're "nibbling away" less steel in each pass, easing the contour or bevel down to what you want instead of trying to tear it all off at once. Sometimes "slower" is actually faster and more efficient.

This is coming from a guy who barely got a C in beginning algebra, so take heart

I'm getting fairly decent at keeping angles consistant by eye, but I threw away a LOT of KSO's along the way. If I were starting from scratch I'd seriously look into getting a bubble jig. In fact, it's on my Christmas list regardless!

James, I think your explanation was more clear than mine.

Good post:thumbup:

I'm starting to think that fred might be right. I spent some time learning to grind and was having a moderate level of success. I happened upon the bubble jig and thought I'd give it a try. Very quickly my lines started to get straighter, quicker! It's not that I couldn't grind before, but the jig takes some guess work out of the process and saves you time. I could grind my bevels pretty clean without it, but only after taking a fair amount of time to straighten and clean things up. With the jig I have less mistakes to fix.

I do like that it is still me doing the grinding. The bubble tells me where to hold the blade, but I'm the one holding it. Without my steady hand and concentration the jig is worthless. I'm not saying I'm in any way an advanced grinder or anything, just pointing out that the jig is not a miracle worker. It needs you to do your part to be successful. I'm enjoying using it in my shop right now and it is saving me lots of time:thumbup:

Thanks for posting Jon:thumbup:

You also explain what I am trying to get across better than I.

Great batch of knives you have going.

Fred

 

[lonepine]

I'm starting to think that fred might be right. I spent some time learning to grind and was having a moderate level of success. I happened upon the bubble jig and thought I'd give it a try. Very quickly my lines started to get straighter, quicker! It's not that I couldn't grind before, but the jig takes some guess work out of the process and saves you time. I could grind my bevels pretty clean without it, but only after taking a fair amount of time to straighten and clean things up. With the jig I have less mistakes to fix.

I do like that it is still me doing the grinding. The bubble tells me where to hold the blade, but I'm the one holding it. Without my steady hand and concentration the jig is worthless. I'm not saying I'm in any way an advanced grinder or anything, just pointing out that the jig is not a miracle worker. It needs you to do your part to be successful. I'm enjoying using it in my shop right now and it is saving me lots of time:thumbup:

Man, was I ever out in left field! Thanks everyone for your patience and holding my hand through this. You don't have to tell me something more than a couple or three dozen times before it sinks in. Duhhhhhhhh...

Embarrassed but smarter,

- Paul Meske
Alias LonePine

 

[james terrio]

No one was born knowing this stuff, Paul. I've beaten my head against a few walls myself

 

[Fred.Rowe]

Paul,

Glad you stayed on the thread. If you picked up even the smallest piece of useful info; it was worthwhile.

Fred

 

[M3mphis]

SO...at the risk of sounding dumb...
When you use a bubble jig and you are grinding around the belly of your blade - do you just keep your eye on the bubble and keep it in the middle as you rotate the blade? I'm assuming that as you rotate the blade on its lengthwise axis, the bubble jig still works to measure your bevel angle because it is an entirely different axis. Is that correct? Did that make any sense?

Thanks!

 

[Fred.Rowe]

SO...at the risk of sounding dumb...
When you use a bubble jig and you are grinding around the belly of your blade - do you just keep your eye on the bubble and keep it in the middle as you rotate the blade? I'm assuming that as you rotate the blade on its lengthwise axis, the bubble jig still works to measure your bevel angle because it is an entirely different axis. Is that correct? Did that make any sense?

Thanks!

No risk involved.

They way do it: I use the jig to complete the rough grind, focusing on the plunge at the ricasso and the bevels forward towards the point of the blade. My main concern is the bevels early on. When I make these early passes, I take the blade straight out, holding the bubble centered and not bother with the multiple radii forward just behind the tip.
Once the bevels are well established and even on both sides of the blade; the jig is removed and I work off the established bevels and finish the grind forward to the tip. Just set the blade down on the moving belt on the flats, forward of the plunges.
The only exception to this is when the edge is developed. I want the edge even from plunge to tip before I step the angle down. The edge is developed first.

Hope this helps, Fred

 

[gnique]

I have two bubble jigs. I have used the bubble jig for about two years. All the experience I have with the jig I have gotten on my own. My experience with the jig may be unusual - I don't know - but someone may benefit from my experience so here goes. When I first used it I thought that it was magic! For the very first time I had straight bevels. I could not believe the results! It was amazing! And then I became dissatisfied. I was dissatisfied because for the first time I had a basis for comparison. I had straight grinds but they were not EXACTLY the same on both sides. It wasn't the fault of the jig, it was my new found ability to FINALLY have a standard to correct from. The bubble jig is NOT magic. It is a tool that demands experience and practice. The wonder of the jig is that it will give you a reference point. It will give you a reference point on the first use. After that it is up to you (alone in your shop) to develop the skill to use it. If I had to make one single comment about the bubble jig I would say that it makes you a LOT more picky about your work right from the beginning. Will the bubble jig allow you to learn in a day what took others a life time to learn free hand? Absolutely not! Nothing will do that except a CNC machine. Will it set you on the right path and give you a stable place to begin learning? Oh yeah!

As all the wise men and women have told us all of our lives - anything worth doing is going to take effort and practice. One of the comments that I have taken from Ed Fowlers several books is the one about playing a piano. He said that a little kid is fascinated just by the fact that a piano makes a sound. A grown man, however, wants to BEGIN playing like Jerry Lee Lewis. That ain't gonna happen. Based on my own experience, a bubble jig will let you start off playing Twinkle, Twinkle Little Star. The path to Rockin' Pneumonia is your own look out. I am now up to Chop Sticks but is is a rockin' ass Chop Sticks! Thanks, Fred. I only got one suggestion - you oughtta call that thing The Stratocaster. Nicholas Jasper

 

[Fred.Rowe]

I have two bubble jigs. I have used the bubble jig for about two years. All the experience I have with the jig I have gotten on my own. My experience with the jig may be unusual - I don't know - but someone may benefit from my experience so here goes. When I first used it I thought that it was magic! For the very first time I had straight bevels. I could not believe the results! It was amazing! And then I became dissatisfied. I was dissatisfied because for the first time I had a basis for comparison. I had straight grinds but they were not EXACTLY the same on both sides. It wasn't the fault of the jig, it was my new found ability to FINALLY have a standard to correct from. The bubble jig is NOT magic. It is a tool that demands experience and practice. The wonder of the jig is that it will give you a reference point. It will give you a reference point on the first use. After that it is up to you (alone in your shop) to develop the skill to use it. If I had to make one single comment about the bubble jig I would say that it makes you a LOT more picky about your work right from the beginning. Will the bubble jig allow you to learn in a day what took others a life time to learn free hand? Absolutely not! Nothing will do that except a CNC machine. Will it set you on the right path and give you a stable place to begin learning? Oh yeah!

As all the wise men and women have told us all of our lives - anything worth doing is going to take effort and practice. One of the comments that I have taken from Ed Fowlers several books is the one about playing a piano. He said that a little kid is fascinated just by the fact that a piano makes a sound. A grown man, however, wants to BEGIN playing like Jerry Lee Lewis. That ain't gonna happen. Based on my own experience, a bubble jig will let you start off playing Twinkle, Twinkle Little Star. The path to Rockin' Pneumonia is your own look out. I am now up to Chop Sticks but is is a rockin' ass Chop Sticks! Thanks, Fred. I only got one suggestion - you oughtta call that thing The Stratocaster. Nicholas Jasper

Nicholas,

Good post; the points you make are right on.

The patent on my invention will be issued next month. Stratocaster has a nice ring to it but the folks at Fender might want to bust my chops over that.

Regards, Fred

 

[Makermook]

When I started making knives a dozen years ago the goal was to make beautiful functional knives; but for some strange reason people wanted to know if the beautiful knives I was making were made without any guide, advanced machinery or other contrivance.
I had never been asked this in carpentry, surveying or welding; why was I being asked this when making a knife?

I believe it is because there is a certain cachet about a "hand" made object...and I've heard people ask the same thing about furniture I've made, as well as knives. It seems more authentic if the dovetails are cut by hand, just as it seems more authentic if a blade is forged instead of ground (in the minds of some people).

While it is true that productivity rises with the use of machinery, jigs, automatic phases of the process, some people do not want a "manufactured" knife; they want a "handmade" knife. That's why the ask about how it was made. If they are told that the maker sweated over a forge and anvil, it just seems like there's more genuineness in that process than if they envision the maker using vernier calipers and a big grinding machine.

This isn't to say that ground knives lack in quality as compared to forged knives. Indeed, unless the smith knows his stuff when it comes to proper treatment of the blade, metallurgically speaking, the stock removal blade sent out for professional heat-treatment is likely to be more structurally sound and durable.

Nonetheless, the reason people ask a knifemaker if he uses machines or not is because of what they *imagine* it takes to make a good knife. The mystique, if you will, of the old-timey smith hammering away is what they think of when they fantacize about knives and swords of yore. Excalibur wasn't ground out of bar stock. Nor were Glamdring or Hrunting or Sting, and as silly as it might sound to talk about mythical magical cutlery, do you imagine that the person asking you about your anvil and forge *isn't* (at least somewhere in the back of his mind) thinking about that stuff?

If they bother to ask about your methods, it's because (I believe) there's at least a small part of them that's envisioning red hot metal and the ring of an anvil as the "best" way to make a knife. Not that they're right, just that that's what they believe.

My 2¢...

 

[Jeremy Horton]

I got a anvil. Should I get a fake santa claus beard too