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Edge Angle

Started by Ric Albano, November 19, 2012, 06:01:52 PM

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Rob



Here's Jeff demonstrating/instructing use of the knife jigs. Move to 4m:40s point, does this answer your question?

http://www.youtube.com/watch?v=fYURcwkKGPs
[/quote]

This knife jig topic comes up quite frequently. My experience when I hit the same roadblock was to review Jeff's video demo very carefully and then practice a lot. Frankly, it worked. I can save everyone a lot of time and energy on this topic.......do EXACTLY as Jeff suggests in both his videos and also following his comments. Don't " think" you have a better way etc, just blindly follow the instructions and stop thinking. Practice this, then practice again, then do it some more....and again.  You'll know when to stop because your knives will have easily good enough bevel consistency and they will be dam sharp.   What I'm trying to say is just have faith in Jeff's method instead of trying to reinvent all the time. There's nothing wrong with exploring new ways of course, I'm simply advocating learning and mastering Jeff's method FIRST. Then move into possible innovation and improvement of your own design. This is what I did.....and it truly works

As a footnote, I now sharpen all but my expensive knives freehand....guess what....they're easily good enough and a billion miles better than all my friends and neighbours.   When it comes to my Japanese jobs, I get the jig out ( don't care how its defined, I care if it works), I practice on two or so cheapies to "re-load" the muscle memory and......grind away....guess what.....it works.

Best.    Rob.

Justin

Quote from: Byoomholay on January 16, 2013, 09:28:52 AM
I can save everyone a lot of time and energy on this topic.......do EXACTLY as Jeff suggests in both his videos and also following his comments. Don't " think" you have a better way etc, just blindly follow the instructions and stop thinking.

Although i don't actually really agree with this rather narrow approach, this case renders it a bit pointless seeing as the original poster is having trouble caused by a known flaw in the jig.

Rob

Quote from: Justin on January 16, 2013, 08:02:44 PM
Quote from: Byoomholay on January 16, 2013, 09:28:52 AM
I can save everyone a lot of time and energy on this topic.......do EXACTLY as Jeff suggests in both his videos and also following his comments. Don't " think" you have a better way etc, just blindly follow the instructions and stop thinking.

Although i don't actually really agree with this rather narrow approach, this case renders it a bit pointless seeing as the original poster is having trouble caused by a known flaw in the jig.

I refer specifically to the issue of how to raise the curved end bit of the blade....this is where Jeff's techniques score dividends.  My point didn't address the non centred jig issue and wasn't intended to. I guess the proper solution to that is an improvement request to the Tormek R&D folks. I was simply stressing that whilst maybe not technically perfect, despite the jig flaw, Jeff's methods when practiced properly are good enough for practical purposes
Best.    Rob.

Rob

Quote from: Jeff Farris on January 04, 2013, 02:36:14 PM
From what Ric has written I think he is not rocking the jig on its axis, but is shifting it laterally. That is what I most commonly see when someone says "the angle gets wider at the tip".

To be specific, this was the point my comment was reinforcing.  IMO folks will improve their results by recognising one fundamental truth which is that the jigs don't replace skill and craftsmanship.  Technique and practice are every bit as important.  Even a jig with a lets face it teensy weensy flaw will still perform perfectly adequately in capable hands.
Best.    Rob.

Justin

Quote from: Byoomholay on January 16, 2013, 08:52:11 PM
"perfectly adequately"  " good enough for practical purposes"

Is that good enough for a professional piece of kit...?

jeffs55

I would not want to show off the sharp edge of anything that cost very much or was a prized possession if the two grinds did not match perfectly. Especially if I was trying to sell a service. Not good enough for a professional kit unless you reclamp the knife to obtain a perfect grind.
You can use less of more but you cannot make more of less.

Jeff Farris

#21
I'm going to jump in here and say that I think a few of you are making more out of this than really exists. In my experience, which includes thousands of knives from customers specifically trying to stump me, it is only on the thickest of hunting/combat knives that I feel it is necessary to re-jig the knife to obtain equal bevels. I have never found it necessary on any standard kitchen cutlery or on the vast majority of folding knives.

Yes, in theory, the jig will only produce a "perfectly" centered bevel on a knife of the thickness the jig is designed for. In practice, the variance on most knives is so small as to be indistinguishable.

EDITED TO ADD:

I'm going out on a limb here and guessing that Ric's problem is one of technique, rather than jig design. "...the bevel widening out at the point..." leads me to believe he is rocking the jig laterally rather than axially.
Jeff Farris

Herman Trivilino

#22
Jeff, this is something I've wondered about since I first started using the knife jig. Does the position of the jig on the knife (closer or further from the knife tip) have an effect on this bevel widening out at the point"?

And as far as this thread is concerned, I agree that we're making too much of the OP's comment. What if the OP is simpling spending more time on one side of the knife than the other? That will make one bevel wider than the other and place the edge off center. Jigs can only take you so far with any piece of equipment. Knowledge, skill, and experience are necessary to get good results.
Origin: Big Bang

Rhino

I agree with Herman that jigs can only take you so far.  Then you need some skills.  To get the skill you need practice.  It is hard to practice on expensive tools because you will end up grinding them all away.  But if you don't practice you can't be good.  So in the end some knives are going to have to be sacrificed to learn the skills - I don't think there is a solution.  This winter I am going to get some cheap knives and learn to hand sharpen on the Tormek.

tb444

The OP's knife is a factory ground, and without any offense intended, isn't a top class knife. go into any kitchen knife shop and look at the bevels on the knives. if you find one with a perfectly centred evenly ground edge you'll be lucky.
From the sound of the post this is the first time he's sharpened it and the tormek bevels aren't matching the factory bevel.

The jig being at fault is the last thing i would presume. My order of probability would be wonky factory grind, operator error, then jig.

Jeff Farris

Quote from: Herman Trivilino on January 18, 2013, 03:56:46 AM
Jeff, this is something I've wondered about since I first started using the knife jig. Does the position of the jig on the knife (closer or further from the knife tip) have an effect on this bevel widening out at the point"? ...

Yes it does, BUT, very, very marginal. If the knife profile is a normal sweeping curve, keep the jig toward the center of the blade.
Jeff Farris

Herman Trivilino

Quote from: Jeff Farris on January 18, 2013, 07:35:05 PM
Yes it does, BUT, very, very marginal. If the knife profile is a normal sweeping curve, keep the jig toward the center of the blade.

What if it's a butcher knife? Towards the tip the curve no longer sweeps, but has a smaller radius. Would you then recommend that the jig be positioned closer to the tip?
Origin: Big Bang

Elden

Herman brought out a great question about clamping that I have been wondering about. Jeff answered it very well.
I ran into that problem on a Gerber survival knife that a young fellow brought me to sharpen. I clamped it right before the serrations began, set the angle, and started to sharpen. Made 2 or 3 passes then realized that I didn't like what I was seeing. The point of contact between the knife and the wheel moved drastically from the straight portion of the knife blade to the point of the knife. The point was contacting the wheel 1 inch or better, further up the wheel which would have made the bevel several degrees more blunt. That was using Jeff's method of lifting the handle.
I shut the Tormek off and analyzed the situation. Knowing Jeff says never, I still tried pivoting the knife instead of lifting it (with the Tormek off). That didn't help the problem. I took the knife out of the jig and parked the Tormek. I then clamped it in my DMT Aligner and proceeded to do as before the Tormek. By the way, the DMT is a great tool and will put just a good edge (or better as double bevels are easily obtained)  if the proper stones are used. However there is one problem, it is a slow process.
Since then I have wondered if it should have been clamped on down the blade above the serrations. Thanks Jeff for the answer! Next time I get that kind of knife, hopefully I won't be parking the Tormek.
As a side note, the DMT Aligner comes with a tapered diamond rod for doing serrations that works well for touching them up. It accommodates different sizes of serrations because of the taper. I also have one made by Buck that does not have the guide that Aligner has.
Elden
Elden

Jeff Farris

Quote from: Herman Trivilino on January 19, 2013, 01:43:16 AM
What if it's a butcher knife? Towards the tip the curve no longer sweeps, but has a smaller radius. Would you then recommend that the jig be positioned closer to the tip?

Here's how I "eyeball" the jig into position for unusual radii. Position the knife in the jig so that an imaginary line from the center of the curve intersects with the shaft of the jig where it meets the stop. 
Jeff Farris

Mike Fairleigh

Jeff, can you clarify that any further?  If the shaft of the jig is centered with the curve of the blade (that's how I - maybe incorrectly - interpret your post), would the knife be fully grasped by the jig?  It seems like the jig would be hanging off the end of the blade, and much of the blade would be unsupported.

This question of where to "jig" the blade is one I've often wondered about too.
Mike

"If I had 8 hours to chop down a tree, I'd spend 7 sharpening my axe."  --Abraham Lincoln