This page addresses grindstones, grinding wheels, and other sharpening media. It is broken up into the following sections:
Honing the tool - a process for getting the edge super sharp.
For carving, this is what is done most often.
Wood turners often overlook this step, but is is really key for getting a beautiful finish on the wood, especially for certain woods like maple.
When resharpening knives, this is often all that is needed to get those edges back into great shape.
Unless the scissors need to have a really honed edge, honing is not recommended for scissors. Stop after the sharpening step (but with a high grit level - 1,000 or so).
Sharpening the tool - a process for getting a tool sharp, and ready for honing.
Take caution when sharpening carbide tools or tools with carbide inserts. Grinding introduces cracks in carbide, and can make it more brittle. It is best to use low grit grinding up to the final angle, and then switch to a high grit grinding for finishing the grinding.
Shaping the tool - a process for gross removal of metal to change the shape of the cutting edge. This is something not done often, so it is listed 3rd.
Some other useful information can be found at these links :
Selecting a wheel for your Tormek machine can be confusing. Sharpening Supplies spoke with Stig from Tormek to help you understand the differences between the different wheels available.
The Basics of Honing | Part 14 | Tormek Live Sharpening Class
In this episode we go through the basics of one of the most important parts of the sharpening process – honing. Honing your edge after sharpening will deburr your edge, which is crucial to get it sharp and durable. In addition, it polishes the edge to give cleaner cuts.
But honing is also a means of maintenance for your edge between sharpenings. Many times, a couple of strokes on the honing wheel is all you need to get that razor sharpness back again. That will save both time and steel!
Key Note: At just past 18 minutes in the video, there are great microscopic pictures showing the effect of different grindstones on the ground surfaces. This is a great comparison of the various Tormek grindstones, but also about typical bench stones and CBN wheels also.
This is why we love diamonds | Tormek Diamond Wheel Special
For todays special episode, Sebastién speaks with Håkan, a real abrasive expert who also happens to be the CEO of Tormek. Together they dive into the details of the Tormek Diamond Wheels (DC-250, DF-250, DE-250). They also discuss the most frequently asked questions about sharpening with diamonds. 💎
+2° is recommended for optimal stropping. The backs of chisel blades are often honed by hand, though jigs are also recommended for other edges as +5° will start to round over the edge.
When in doubt, follow Wootz' rule, "the softer the steel, the higher the angle". Really hard steels could have this decreased to +1.2°.
Finely honed edge from this stone is especially useful for finishing cuts
Use a diamond grinding wheel for tools with vanadium levels >3%.
Do not use diamond wheels for tools with ferrous metals unless they are cooled (e.g., with water). Hot iron molecules can dissolve diamonds, quickly eroding the surface.
A common rule of thumb is "Better to do two quick passes than one slow one" to minimize edge softening with heating.
I use the 8 inch wheels on a 6 inch grinder.
Cubic Boro Nitride (CBN) Wheel
very high grit (800+) CBN
Use a CBN grinding wheel for tools with vanadium levels >3%.
Most CBN manufacturers recommend not using the CBN wheel with water. It can invalidate the warranty.
CBN wheels are not recommended for tools with high carbon steel. Those and other softer steels can "gum up" the wheel's surface. That said, a person I cannot remember has stated that grinding high speed steel (HSS) on the CBN wheel will clear the "gumming".
Resins accrued on tools when turning wet woods can also gum up the grit. Trend lapping fluid was recommended (on an AAW forum) by Reed Gray (aka, "Robo hippy") for cleaning the wheel.
Good all-round wheel which leaves a smooth surface finish
Use a diamond grinding wheel for tools with vanadium levels >3%.
Do not use diamond wheels for tools with ferrous metals unless they are cooled (e.g., with water). Hot iron molecules can dissolve diamonds, quickly eroding the surface.
Be sure to manage the temperature so that the temper is not lost due to overheating.
If there is a carbide insert, then DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks.
Otherwise, dip it frequently in water.
Bench Grinder
Traditional Grindstone
150 - 180 grit, very friable grindstone, such as aluminum oxide
Friablility reduces (but does not eliminate) the heat build-up.
Be sure to manage the temperature so that the temper is not lost due to overheating.
If there is a carbide insert, then DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks.
Otherwise, dip it frequently in water.
Truing the stone may be necessary.
80 grit silicon carbide (green) is recommended for tools with carbide inserts, and especially for stone carving tools.
Cubic Boro Nitride (CBN) Wheel
150 - 180 grit CBN
Use a CBN grinding wheel for tools with vanadium levels >3%.
CBN wheels are not recommended for tools with high carbon steel. Those and other softer steels can "gum up" the wheel's surface. That said, a person I cannot remember has stated that grinding high speed steel (HSS) on the CBN wheel will clear the "gumming".
Resins accrued on tools when turning wet woods can also gum up the grit. Trend lapping fluid was recommended (on an AAW forum) by Reed Gray (aka, "Robo hippy") for cleaning the wheel.
Bench-mounted Belt Sander
150 - 250 grit
Belt Grinding notes
Be sure to manage the temperature so that the temper is not lost due to overheating.
If there is a carbide insert, then DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks.
Use a diamond grinding wheel for tools with vanadium levels >3%.
Do not use diamond wheels for tools with ferrous metals unless they are cooled (e.g., with water). Hot iron molecules can dissolve diamonds, quickly eroding the surface.
Be sure to manage the temperature so that the temper is not lost due to overheating.
If there is a carbide insert, then DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks.
Otherwise, dip it frequently in water.
Bench Grinder
Traditional Grindstone
<100 grit, very friable grindstone, such as aluminum oxide
Traditional Grindstone notes
Friablility reduces (but does not eliminate) the heat build-up.
Be sure to manage the temperature so that the temper is not lost due to overheating.
If there is a carbide insert, then DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks.
Otherwise, dip it frequently in water.
Truing the stone may be necessary.
Cubic Boro Nitride (CBN) Wheel
<100 grit CBN
Use a CBN grinding wheel for tools with vanadium levels >3%.
CBN wheels are not recommended for tools with high carbon steel. Those and other softer steels can "gum up" the wheel's surface. That said, a person I cannot remember has stated that grinding high speed steel (HSS) on the CBN wheel will clear the "gumming".
Resins accrued on tools when turning wet woods can also gum up the grit. Trend lapping fluid was recommended (on an AAW forum) by Reed Gray (aka, "Robo hippy") for cleaning the wheel.
Bench-mounted Belt Sander
<150 grit
Belt Grinding notes
Be sure to manage the temperature so that the temper is not lost due to overheating.
If there is a carbide insert, then DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks.
Otherwise, dip it frequently in water.
Notes & Comments
Thank you to Bobby Smith for the information regarding the Sorby ProEdge grinding media.
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.
