Sharpening for a better burr

[Ken S]

Point very well taken, Herman. In our attempt to convert an efficient handheld sharpening set up to a method assisted by a platform, we have overlooked the benefit of just using the platform (HK-50) as is. The reason for Steve choosing the eighteen degree position is to be able to hold the knife blade in a flat position. This makes sense as an aid to handholding.

Sharpening knives handheld is definitely fast in skilled hands. I believe "the bridge" offers some benefits for those of us who do not have finely honed manual sharpening skills. Does being able to position the knife in a horizontal position as opposed to being at an angle offer any advantage? I put this as a question because I don't have an answer at this point.  Thoughts?

Again, good thought, Herman.

Ken

[Ken S]

Interest thought, Jan and Doug.

Ken

[Elden]

   Holding an object (flat side of a knife in this case) parallel with the floor, is more easily accomplished than guessing at a certain number of degrees. The method Steve B showed in Sharpening Made Easy, then required  bringing the knife down the circumference of the wheel to the appropriate mark drawn on the wheel.
   My mind comprehends parallel and perpendicular to the floor more easily than 15, 18, 20 degrees or other angles. However through the years, I have formed  fair perception of the 59° angle used for grinding most drill bits. So I guess it comes to what one becomes accustomed to doing.

[Rob]

In the final analysis, all the freehand techniques are simply down to the muscle memory that is developed through practice.  There is just no substitute.  Follow the suggested guidance with inexpensive knives bought from a flea market or similar for a dollar a piece and grind them until they're gone.  Try it at 45 degrees, try it perpendicular.  Grind off the edge all together and then re-establish it.  My point is that by grinding at the 2 outer extreme angles, your mind and muscles will develop an intuitive understanding of the total scope of angles.  As you focus down into the range that's actually useful from pairing to chopping it will become more like driving a car.  I was rubbish at grinding freehand until I started turning. The tools felt ham fisted in my hand and it was a miserable experience.  As I started using turning tools more and more, it necessitated doing unusual grinds to give odd shaped edges and angles for cutting the sides of boxes or doing dovetailed recesses for chucking points etc etc.  The skills to hold the tools carefully and steadily come and come surprisingly quickly.

I would really encourage people to ditch the fear of freehanding and indeed begin the experience (with cheap knives) fully expecting to be rubbish but still to persevere for an entire afternoon one weekend if possible.  Or spend an evening doing nothing but grinding.  The skill does come quickly when you keep at it and boy does it save a lot of faff and setup time!

The other thing turning has taught me is try not to get too worried about your angles being spot on.  The truth is it just doesn't matter, the thing will still cut!  Professional turners work to a tolerance of +/- 5 degrees....yes that much and guess what....their arms simply adjust imperceptibly to have the tool work correctly anyway.  Now of course I appreciate a knife isn't the same as a bowl gouge but I do believe that the principle is the same which is to say we get terribly wound up and stress about the precision of the angle when in fact a target range of angles is almost always good enough.  Obviously we need to exclude precision edges like salon scissors from this...I'm talking kitchen knives etc.

But have a go, put the necessary miles in to learn to drive and I promise you'll be pleasantly surprised at the results.  This really isn't rocket science :-)

[Jan]

   Holding an object (flat side of a knife in this case) parallel with the floor, is more easily accomplished than guessing at a certain number of degrees.

I agree with you, Elden. 

Today we have had a hot day here, so I decided to spend it in the shop which is fortunately situated in the basement. The hot weather enabled me to build a prototype of a flat, height-adjustable platform for Herman's knife jig. The laser line extension is of course there!

In the image below you can see how it was assembled. I used massive steel square, drilled two holes for M12 (1/2")  bolts, which anchored this support into the vertical sleeves. I added one low nut as a micro adjust.  Then I bolted small steel plate to the longer arm of the steel square. This plate can serve as horizontal tool rest.



Herman's knife jig was made of aluminium strip of 1/8 " thickness. Its edge was grinded on a belt sander to some 20 degrees. Herman's knife jig rests on plywood block to provide some clearance for sharpener's hands.

The red laser line on the wheel is adjusted for grinding 18 degrees angle. The horizontal distance between the edge of the Herman's knife jig and the wheel may be as low as 0.04"

The whole jig can be flipped over to enable grinding away from the edge. 

Jan

[SharpOp]

Easier and faster to use the Angle Master to repeatedly, individually, set the bevel angles of successive knives than to set the laser level (and/or a version of your platform jig) once for everything-at-18-degrees (or something like that -- most kitchen knives)?

I think we might have a disconnect here, cuz I don't understand how that could be.  What did I miss?   

I can set the platform to an 18 degree angle quickly and easily using the Angle Master. Once that's done I can sharpen as many knives as I want at an 18 degree bevel never again needing to measure anything.

Oh, I knew that, obviously.  Now I think I understand what you meant.

I'm not sure whether or not you can set the grinding point on the stone faster with the Angle Master than with a simple procedure (known or calculated position on circumference measured from TDC); or a template that does essentially the same thing (flexible strips marked in bevel angle degrees -- you can have several for varying stone diameter); or a bespoke Tormek grindstone protractor.  I doubt it, but it doesn't matter much, anyway, since it's only done once per bevel angle setting.

[SharpOp]

Brilliant, Jan.  A huge step toward a workable laserized version of Herman's platform knife jig.

And I just happen to have some spare steel squares.   

[Jan]

Thank you for your kind words and for your support, Doug! 

I'm glad, I was able to easily resolve two things at once. To build Herman's knife jig and also the flat, height-adjustable platform.

Jan

[grepper]

Very cool!  Great work, Jan.

Amazing how the Ionut/Herman/Ken/SharpOp/Jan thing is evolving.  Now with laser!

From the looks of things it won't be too long before:
http://forum.tormek.com/index.php?topic=2319.msg11271#msg11271

[Jan]

Thank you for your kind words, Grepper!

Your post from late last year was truly a visionary! 

Jan

[Ken S]

Jan, you are quite the engineer!

Ken

[SharpOp]

From the looks of things it won't be too long before:
http://forum.tormek.com/index.php?topic=2319.msg11271#msg11271

But we're getting laser assistance along with creative elegance like Jan's framing square  mount.  Definitely looks like best-of-class DIY culture to me.

Now, for a reservoir circulation, filtration and power-draining system using old aquarium components.  And/or a redesign of the water trough retention system.   

[Ken S]

How about temperature control?

[Jan]

I want to thank you all for the recognition and support.  I appreciate it.

I think, my jig prototype, is the result of the collective efforts of this forum. The situation was mature, and it was by chance me, who made that step forward.

On this occasion, I would like to quote Antoine de Saint-Exupery "When by mutation a new rose is born in a garden, all the gardeners rejoice."

Jan

[Ken S]

Great quote, Jan  I totally agree.

One of  the happy Tormek gardeners