by George Ligon
I am following up our discussion the other day with some more information as well as some other information that I promised at our March 2020 meeting. Note, these are my opinions and some may not agree with me for whatever reason they may have. Doesn’t make me or them right or wrong.
First, I must apologize for any confusion I may have made, at the meeting, as it has been ten years since I’ve done any significant sharpening and all that stuff on the table I had to unpack after ten years storage and practice on it before our meeting. Second, I am rethinking my recommendations for an 8” grinding wheel set up for sharpening your chisels and plane irons.
Do you really need a grinder? Yes and no. If you ever have a tool that is somewhat out of shape, you can work it back into a good tool again, but it will take more work and time without a grinder. I was basing my original recommendations on my experiences and perspective. I have had to do a lot of restoration of both older and newer plane irons and chisels. Many of these tools were significantly out of ‘shape’ and I needed a grinder and then, later, the Veritas system to get them back into shape. Once back into shape from work on the grinder, it then becomes easy to bring back a worn out or dull edge to razor sharpness in a short time with honing and stropping. This can be easily done with the different types of jigs and stones of which I had several and showed then to the group. I’ve done some more reviewing and highly recommend the Veritas jig I showed to everyone. There is a good video here on the use and comparison between a basic jig, a Lie-Nielsen jig and the Veritas jig. In the end, the reviewer recommends the Lie-Nielsen jig.
I’ll stick with my recommendation of the Veritas jig for several reasons. This jig has several attachments I like: 1. An additional roller that allows for sharpening a convex edge on plane irons. A convex edge or not on a plane iron depends on how you are going to use your plane. 2. The ability to easily change the sharpening angle by one or two degrees thus allowing the ability to easily hone the micro bevel for a longer time before reworking the cutting tool back to its original angle by honing.
So, with that being said, a grinder will help speed up the sharpening process when a tool chips an edge or needs to have the 25º bevel renewed. Or if you find yourself with any restoration needed on some old tools, a grinder then becomes necessary. Here is my recommendation for a basic inexpensive grinding station.
Recommendations for Setting Up a Basic Sharpening Station
The link for the 8” Rikon Slow Grinder at 1,750 rpm with 60-grit and 120-grit white aluminum oxide grinding wheels and 1/2- HP motor, about $117. I’ve been using a Delta 1/2-HP with a grey aluminum oxide wheel for sharpening and heavy steel grinding successfully for many years now and am happy with its power. The only negative I see with the Rikon grinder are the eye shields which are hard to adjust and keep set up properly. My grinder has very similar and although I would like to use them, I’ve ended up pushing mine out of the way. There is a 1-HP version that goes for $245 with better eye shields and a set of magnifying ones too that look to have a better way of securing and adjusting the eye shields. As I said though, I do not believe you need the extra power in a sharpening grinder.
The reason for recommending white aluminum oxide grinding wheels is because they don’t create as much heat as the grey aluminum oxide wheels. You want to keep the heat as low as possible, when grinding your tools, as too much heat (turns blue) can ruin the heat treating of your tool thus ruining the durability of the cutting edge. More on overheating your tool later, see “Overheating the Cutting Edge” below.
If you are going to be doing some restoration work on some old tools you might think about using one standard grey aluminum oxide wheel and one white aluminum oxide wheel.
Why do I recommend an 8-inch grinder over a 6-inch?
A 6-inch wheel gives you a more pronounced hollow grind which is not as desirable as the grind from an 8” wheel. While you can get a final 30º angle on both grinded tools the 6” grind does not have as much metal supporting the tool cutting edge, it’s thinner, thus making it harder to dissipate heat away from the cutting edge as well as not having as much metal supporting the edge. There are also different ways or angles of approaching the grinding wheel with your tool that can affect this.
The Veritas tool rest for replacing the standard grinder tool rest. This tool rest is a great addition, but not necessarily a must. $61 To properly use this your grinder and tool rest must be secured to the bench. Other versions of this tool rest, on Amazon, go for somewhere in the $30 range.
Link for upgrading your existing 8” grinder to Norton white aluminum oxide wheels. About $30 each.
As I said above, the Veritas type tool rest is not a necessity. I have sharpened many tools on the standard grinder tool rest and an 8” grey aluminum oxide wheel with great success. It just takes a bit more time and patience to keep things straight and square.
Overheating the Cutting Edge
When sharpening cutting tools on a grinder you need to avoid overheating the tool cutting edge. If it gets so hot that the metal turns to a straw to blue color you have ruined the present cutting edge and have to grind back past the bluing. However, it is not good enough to just grind enough to get rid of the blue color, which is easy to do. The hardness is lost deeper into the tool edge than the coloring created from overheating. How deep will be hard to determine but it is not good enough to just get rid of the color of bluing. The rule is to avoid the overheating in the first place.
One reason why I am recommending the white aluminum wheel for grinding because it runs cooler. So, we also can quench the tool while working on the grinder by dipping the tool into a small container of water close by the grinder. Sometimes there is too much information on the internet to get things confusing as I ran by an article suggesting not to quench because it can cause too much stress in the metal, in turn creating small microscopic cracks. I cannot find that article again but can find no others recommending against quenching. For very many years, and still today others are recommending using water to keep the tool edge cool. My compromise, if this is true, would be to quench more often before the tool gets too hot or take more time grinding to avoid getting the tool too hot in the first place.
If anyone is interested in talking more about this subject or wants to see the jigs I have and see how they are used please feel free to contact me and come on by my garage shop.
Stay healthy, George Ligon
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