edge grinding help

Cameron Wilcox

Well-Known Member
I got Fred Rowes Bubble jig and practiced on a few cheap kitchen knives then went on to try on my first knife... long story short the kitchen knives didn't have enough belly to practice on and I messed up.
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the first side. only off near the tip


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here is the side I really goofed on.

Any advice as to what I am doing wrong? the edge looks fine until it gets to the belly.
 
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Hi Cameron,

Are you wanting to set the edge on a newly ground blade or are you sharpening knives? In booth cases you need to drop the butt end of the knife down and rotate your wrist. Forget about referencing the bubble as you work around the belly of the blade on through the tip. If you are getting good results along the straight area of the blade and only having trouble when you hit the belly, you are on the right track.
Working on a good size tool rest helps a lot. It makes for much steadier hands and with that much closer tolerances on your grinds.

It takes practice no matter how you go at it.

Give me a call if you want to talk, Fred
 
Hi Cameron,
I use a 20 degree block on a flat work rest to sharpen my knives edge up, before handles are installed, but that probably will not help you much. Doing the belly or tip of the knife should be like doing a hollow grind, once your grind starts leaving the strait part and getting to the curved part start pulling the handle of your knife towards you in a smooth motion til you get to the tip. Does not take much pressure! Practice practice ! Lot easier to show you than describe it, hope this helps!
Clint
 
That's THE major issue with using any kind of a jig when it come to grinding....a jig generally will allow you to grind a specific type/shape of blade well (usually it's the type/shape that the jig's maker used when developing the jig) but for anything else it's a challenge at the very least. I always encourage folks to practice, and learn to grind freehand. To do so means that you will be able to grind just about any blade type/shape. The same goes for sharpening....each blade you sharpen is going to be a little different, and if you have the mindset that that your going to put a specific "angle" on all the knives you sharpen, then your not only shorting yourself, but the customer too. I have to admit that I cringe whenever I hear/read discussions on "angles" used for sharpening.....personally, I prefer a convex edge, which creates far less cutting resistance, and for me is so much easier to adjust from knife to knife versus a specific angle.

From the photos is appears that your trying to use the jig for sharpening purposes. Judging by the photos, and the huge bevels it created, It's doing more harm than good. Those huge bevels are nothing more than cutting resistance that you're building into the knife. On that particular blade, my opinion is that the primary bevels would need to ground down in order to ensure you get as little edge bevel as possible in the finished product.
 
on this one I was trying to clean up an edge I had already put on. also another question, what grits do you use for edge grinding?
 
That's THE major issue with using any kind of a jig when it come to grinding....a jig generally will allow you to grind a specific type/shape of blade well (usually it's the type/shape that the jig's maker used when developing the jig) but for anything else it's a challenge at the very least. I always encourage folks to practice, and learn to grind freehand. To do so means that you will be able to grind just about any blade type/shape. The same goes for sharpening....each blade you sharpen is going to be a little different, and if you have the mindset that that your going to put a specific "angle" on all the knives you sharpen, then your not only shorting yourself, but the customer too. I have to admit that I cringe whenever I hear/read discussions on "angles" used for sharpening.....personally, I prefer a convex edge, which creates far less cutting resistance, and for me is so much easier to adjust from knife to knife versus a specific angle.

From the photos is appears that your trying to use the jig for sharpening purposes. Judging by the photos, and the huge bevels it created, It's doing more harm than good. Those huge bevels are nothing more than cutting resistance that you're building into the knife. On that particular blade, my opinion is that the primary bevels would need to ground down in order to ensure you get as little edge bevel as possible in the finished product.

Hi Ed,

I follow your post and your advice on many knife related subjects and believe your years of experience give you an invaluable insight in many areas of knife making.
In this case I feel a little input from the designer and patent holder of the "jig" that Cameron is using should offer his viewpoint.

The Bubble Jig was designed by a knife maker for knife makers. I have personally ground 500 plus blades using this tool. Using it does not restrict the grinder in any way; it does just the opposite, it makes possible, even to the novice, many grinds that the blade maker would not believe possible "free hand"

It in no way limits the type, shape, style or size of blade that a maker might want to grind.
I personally grind fighters, bowies, daggers, sword blades and little folder blades big ones small ones and with many different angles and I can reproduce the exact same blade at any time, just by referring to my knife list. Three degree bevel with a 10 degree edge. It allows the person grinding to select any angle he chooses. I know you will agree that all blades do not reach their potential using only one type edge or one angle of bevel. Some work best flat, others do best with a hollow grind. IMHO convex grinds do their best work on knives used for chopping. I do agree that a convex edge is easiest to grind whether on the bevel itself or the edge; but all blades are not the same, each is used for its intended purpose and therefor requires its own grind.

Personally I don't know how to discuss knives without using angles as the reference. If your talking about bevels and their geometry then your talking about angles. If discussing edge geometry, that has to do with angles relative to the bevels.

The Bubble Jig makes it possible to both develop a new edge or to sharpen knives at any angle desired. Cameron does not have my years of experience using this tool; but I can put an edge on any blade in just a couple of passes. Convex grinds do have there rightful place in blade and edge design, but it is not a grind that works in ever situation.

I think the large bevels on Cameron's blade edge indicates the bevels were not ground to a zero edge and has nothing to do with using the jig.

A story that Wayne Coe told me a while back, I would like to share with you; He told me he had been knocked off his pedestal, by a young mans remarks when the youngster said he wanted to grind a dagger after grinding with the Bubble Jig, with Wayne as instructor , for a very short time. Wayne said now just about anyone can grind a dagger; he said the pedestal was a little hard to stand on anyhow.

Have a good one Ed. Its always nice to read your post, Fred
 
No offense intended Fred....sorry if it came out that way. At some point in time I may have to eat my words about using jigs, but at this point I simply think they create too much of dependency when it comes to young/new makers. I've had far too many students come to me for classes, that got here, and when it came to the grinding portion of the class, asked me..."Where's your jig?" When I told them that we don't use grinding jigs here, they were completely lost, and had absolutely no idea about how to grind a blade without one. I also noticed that those same individuals who had started out with a jig, and had become dependent on it for grinding blades, also had little or no skill in using the various aspects of a belt grinder to their advantage.

Now, I will temper all that I have said to this point by adding...I have no personal problem with someone who uses a grinding jig to expedite their grinding or for repetitious operations...that's just good common sense. However, if it's used to circumvent the necessity of learning how to grind, then it becomes a crutch, and a serious limiting factor to an individual's learning curve and skill set.
I have to wonder if that "young man" you mentioned would ever have made the effort to learn how to grind a dagger, if he had not had a jig, which made him believe he could be successful without any "learning curve? It's not that I am against all grinding jigs......it's that I'm against "new" makers becoming so dependent on them that they never give themselves a chance to build a skill set that will enhance their abilities and the overall quality of their knives over the life of their careers.
 
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I know I've participated in a handful of discussions on jigs (particularly Fred's Bubble Jig) in the past, but let me first preface this post by saying that Fred's bubble jig is probably the ONE jig I would recommend to a beginning maker.

That being said, there is a small caveat to that recommendation, which of course isn't to single Fred's jig out by any means, but to speak of jigs in general, including Fred's.

I'm not sure that I would recommend that anyone START on a jig (including Fred's) but learn where exactly the mistakes come from, and even how to fix them first, before you start using "help". I think this will only enhance the usefulness of any jig in the future, once you understand how exactly that jig is helping you.

THAT being said, I still wouldn't continue relying on a jig to grind blades OR edges, but only to use it as a stepping stone to learning how to free hand.

Now, I'm not gonna say to do what you can to learn how to free hand and never ever use a jig again. I do think they have their occasional place in knife making. At the same time, I think a maker severely limits themselves to rely ONLY on jigs and guides. I might even go as far to say that for every 5 blades you grind with a jig, you should grind at least 5 more free hand, so that you can more easily and automatically adapt to any grinding situation that might arise.

Repeat this process until you can't notice any differences between the two sets of blades. ;)
 
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I was not offended by your post Ed. I'm to old to take offense and your words were not offensive.
I understand your position and agree with you, do not box yourself in as a maker keep all your options open and strive to be as creative as you are capable of being.

You have been doing this longer than I have and have seen them come and go. People buy a grinder and a drill press and think thats all there is to it. You are a knife maker; which of course your not. There is a considerable amount of learning that goes along with the machines you've purchased.

No single tool is the key to success; not my jig nor any grinding machine or any other tool that helps you achieve success.
My thinking in the beginning, when I was considering applying for a patent on this, was never centered around money. God knows thats true. It was about sharing a tool, with others that wanted to make knives and in sharing, help them to reach their goal. It has done just that for hundreds of knife makers. This little tool is a wonderful teacher. First timers can grind a knife blade that they are excited about. They are so pleased with themselves and filled with such confidence that they go on to become actual knife makers. They don't need to train with an accomplished maker. They can learn on their own. I can put names too 400 makers on this forum and others who have been grinding for a year or two using this little tool and have become accomplished. I like that; I like it a lot.
They are an asset to the knife making world and thats wonderful.

So we are not really far apart as to what the goal is. Our approaches are slightly different but our hearts are in the same place.

You hear it everywhere "Be all you can be" and I truly believe that; no matter what you are shooting for.
Thanks for your response Ed, I appreciate it, Fred
 
Thanks for your post AR. I like to see you enter the conversation. Your views are always expressed well and add positively to the discussion.

Regards, Fred
 
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