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