Why 139mm?

[Ken S]

Some of you may be curious about the choice of 139mm Projection with the knife jig. (140mm is typical for Wootz. I attribute the 1 mm difference as being caused by being from different hemispheres.     )

On a serious note, there is a logical reason. When I was developing the kenjig, I wanted to find one Projection which would work with all of my kitchen knives. I measured my chef's knife and slicer in the SVM-45 with both minimum and maximum projection. With both of these types of knives, there was a common range of a few millimeters. 139mm fell in the middle of this common range.

So, the 139mm (or 140mm) is determined by the length and screw thread length of the SVM-45.

The only knives which don't fit the 139mm direct projection are small paring knives. I adapted to this by using the SVM-00 in the SVM-45. This allows the 139mm common Projection, however, it seems clumsy to me. I recently discovered that the pre 2002 knife jigs are lomger, with considerably longer thread length. These older jigs will allow my universal 139mm common Projection. I am presently looking for a pre 2002 SVM-45.

Ken

[John_B]

Ken, since your jig is so easily made why don't you just make one for the paring knife?

When you sharpen knives do you also hone at a slightly greater angle as Vadium suggests in his book?

[Ken S]

Very good questions, John.

Yes, I have made a separate kenjig for paring knives. I use 125mm with it instead of 139mm. It works fine, and, for a more rational person would be a very acceptable final solution. For my own very low volume sharpening, using two Projections with different kenjigs is no problem. However, my goal has always been the simplicity of one Projection and one Distance for grinding. Before the Covid19 lockdown, I was planning to visit my local machine shop and have a longer threaded handle made for my SVM-45. This would require using the older adjustable stops with the locking screws. This is not a problem, as I rarely need to adjust the stops.

I learned that prior to 2002, the Tormek SVM-45 and SVM-100 jigs were longer and had a 35mm longer threaded area. The SMV-100 I use for slicing knives has this longer construction. I am presently looking for a pre 2002 SVM-45.
If I can't locate one, I will have my local machine shop fit my SVM-100 handle refitted to an SVM-45.

I am presently rethinking my knife sharpening technique. I settled on 15° bevels many years ago. Based on Wootz' research, I am in the process of converting to 12°. Also based on Wootz' research, I plan to convert to a slightly higher honing angle. I have always thought of the kenjig concept as a work in progress.

Thanks for your questions.

Ken

[John_B]

I use 2 USB's one set for my desired honing angle and the other for sharpening. I use the FVB for my honing.

I also like the idea of setting a standard angle for your knives. I do keep one older heavy knife sharpened at 20° for attacking chicken. With just 2 of us here the big packs of chicken parts do not make much sense. I get a whole chicken and in a few minutes I can break it down for parts. This way I get bones for stock and parts. I will sometimes chop it into smaller pieces for stir fry.

I must admit that my personal sharpening has diminished quite a bit since I adopted a 4 hone system. Everytime I pick up a knife I will steel it with the smooth steel. WHen I start to see a perceptible change in sharpness I will use a grooved steel and cycle back to the smooth one. After a while when this is not effective I hone with a 2000/3000 ceramic rod and cycle back ending with the smooth steel. My fourth cycle I use a 1000/2000 grit ceramic rod. This takes longer to type than it does to execute. I have been able to keep my knives very sharp using this method.

[Ken S]

Interesting thoughts, John.

The idea of using multiple usbs occurred to me while watching Jeff Farris in his turning DVD. Jeff had a preset, dedicated usb and SVD-110 platform for sharpening turning scrapers. I have found extra usbs useful for many uses, especially the larger US-430.

My wife and I eat very little meat, although your heavier 20° knife makes sense to me. I originally made kenjigs in both 15° and 20°, although I don't remember using the 20° jig.

Must dash....more later.

Ken