Sharpening Handbook

Marking Knives

Guidelines shown below are for Included Angles (⍺).

Notes about Secondary Bevels are at the bottom of this page.

If you want to get truly sharp, KnifeGrinders has a really good method and has adapted the Tormek system to these wheels. He's been nice enough to provide pictures.

Jan Svancara posted a design for using a knife sharpening platform in 2015 on the Tormek Forum. This is certainly worth reading, and there are also pictures of this in the jigs section.

CB created an excellent USB Projection Calculator which can be used to calculate the settings you will need to use with the Tormek knife jigs. His calculations have been vetted for accuracy to the sub-degree level, so I recommend this over the one I'd previously created.

General Guidelines
Marking Knife	25º	+2º	Included angle is the same as the bevel angle as only one side is beveled. The back is flat, and it is fundamentally sharpened as if it were a woodworking chisel. Generally, there is a 120º angle on the leading V. Some chose to round off the pointed tip. The Tormek SVM-45 works well for these.

General Guidelines

Type

⍺

Secondary (Micro) Bevel

Notes

Marking Knife

25º

+2º

Included angle is the same as the bevel angle as only one side is beveled. The back is flat, and it is fundamentally sharpened as if it were a woodworking chisel.

Generally, there is a 120º angle on the leading V. Some chose to round off the pointed tip.

The Tormek SVM-45 works well for these.

Notes & Comments

Information regarding Grindstones

Secondary Bevel Notes :
- Some recommend a secondary bevel angle of +5º, even up to +10º. That is a decision the user should take over time.
- Dr. Vadim Kraichuk's research showed that +0.4º is recommend for the best sharpeness (see also, "Sharpeners Report", February 2018).
- Once this becomes too time consuming (i.e., the secondary bevel becomes too large), then you will have to regrind the primary bevel.
Online Calculators that can be used for sharpening knives.

Research Articles, Other Information, and some Final Thoughts.

It is a common, but quite bad, practice of drawing the newly sharpened knife edge through a piece of wood or some other media to “rip off” the remnants of the burr. When this is done, the ripped off metal builds up on the front of the slice, and you then drag the rest of the edge through this crud. This crud, together with breaking off of ledges of material along the edge, will roughen the edge and worsen sharpness.
The following scanning electron microscope (SEM) images show the burr on a knife in the 1st image, that was then “ripped off” by cutting cross-grain into a piece of redwood in the 2nd image – loss of the sharp edge is obvious.

Click on either image for bigger size.
Images courtesy Todd Simpson via Dr. Vadim Kraichuk of KnifeGrinders
Key take-away from these photos : don't skip the honing step.

Good videos showing use of the Tormek KVM-45, KVM-100, and KVM-140 Knife Jigs, and the SVM-00 Small Knife Holder :

Good videos showing use of the Tormek WM-200 AngleMaster :

Tormek AngleMaster WM-200

Good video by Herman Trivilino showing the use of a platform jig :

Tormek Knife Jig

Good videos by Knife Grinders showing sharpening of knives with complex curves :

Convex
Concave
Mounting the Pin Pivot Collar on your Knife Jig

Pin Pivot Jig

Tormek is a copyrighted logo of Tormek AB. Its presentation on this site is used to help the user quickly understand when specific Tormek tools, jigs, or setting are being used. For specific information regarding Tormek AB, or its products, please refer to the www.Tormek.com.