Guidelines shown below are for Included Angles (α).
Japanese marking knives are typically sharpened only one side. For those,
α = β
The Projection Calculator is available for calculating setup for Tormek knife jigs. This one is web-based and does not require Excel.)
CB's USB Projection Calculator is also available for calculating setup for Tormek knife jigs.
A knife is only as good as the one who wields it.
Patrick Ness
General Guidelines
Type
α
Point Angle
Notes
Recommended Tormek Jigs
Marking Knife
25°
120°
When looking at the blade from the side, generally it has a 120° angle. Some chose to round off the pointed tip.
A micro bevel is not usually used on this as the sharpened surface area is so small that this is not needed to make re-sharpening easier and faster.
Setting a small nose radius of 0.007 in. (0.2 mm) is a good idea. If it is too pointy, the blade's tip can rip at the wood fibers.
The shape of the grind used is a call best made by the tool's use, based on their own experience. Additional notes are available on separate web pages for:
How To Sharpen A Scandi Grind (YouTube video) - This video Tom discusses less about how to sharpen a scandi grind than a lot of tips on sharping this grind profile.
Dave Jeske Sharpens a Marking Knife (YouTube video). Dave Jeske, the founder of Blue Spruce Toolworks, shows the simple way to sharpen a spear-point marking knife. Plus, he shows two simple tricks you can do on the sharpening stone that will make you knife work even better.
Why Felt for the Wire Edge (YouTube video). Dr. Vadim Kraichuk with KnifeGrinders has posted this video on why felt is best to remove the wire edge when honing a knife, and why they chose the hardness of felt that they sell.
Tormek Live Sharpening Class - Part 9 - Sharpen a flat bevel with Tormek MB-100 on a diamond wheel (YouTube video). In this episode we learn how to use the Tormek MB-100 Multi Base to sharpen a completely flat bevel ▼, on the side of Tormek's diamond wheels DC-250, DF-250 and DE-250. For some tools, such as 🎻 luthier knives,🔪 Kiridashi knives, v-tools, chip carving knives and Japanese plane irons, a completely flat surface on the bevel is preferred over a slightly concave, which you get when you sharpen on the rounded part of the grinding wheel. For some people this is more of a personal preference.
Regardless of what might be the reason to want a flat bevel, Sèbastian and Wolfgang show how to achieve it with your Tormek wet sharpening system, They will also touch upon the differences between the different types of bevels.
Tormek Live Sharpening Class - Part 15. Repair a damaged knife (YouTube video). Wolfgang and Sèbastian from Tormek show you how you can repair damaged knife on your Tormek sharpening system If your knife has a chipped edge, a broken tip, or if it has started rusting, you can often repair the knife and make it as good as new.
Click on either image for bigger size. Images courtesy Todd Simpson
via Dr. Vadim Kraichuk of KnifeGrinders
If you want to get truly sharp, Dr. Vadim Kraichuk with KnifeGrinders has a really good method and has adapted the Tormek system to these wheels. The KnifeGrinder method is one that is proven, and has great tools to assist with making it easy.
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 scanning electron microscope (SEM) images to the right 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.
Key take-away from these photos : don't skip the honing step.
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.
Remember : The goal of sharpening is to produce sharp tools, and these tools can injure you if mishandled. Safety measures should be followed to protect yourself and those in your shop. Be sure to read and follow all instructions from the manufacturer, and and utilize proper safety equipment. Never consume alcohol or anything that could impair your judgement before sharpening tools, or using sharp tools.
Comments can be sent via eMail to me at SharpeningHandbook@Gmail.com.