Hand Tools Archive

My current thoughts on sharpening *PIC*

Bill Tindall, E.Tn.

My need for sharp blades

I mainly make shavings in order to adjust the size or shape of a piece of wood, that is, largely for fitting. I sand everything so surface finish is irrelevant. If wood goes away in a controlled fashion, tear-out free, I am satisfied.

Fitting tasks come in short spurts so I never plane anything close to dulling the blade in one planing session. Hence, when I grab a plane or chisel it is unlikely I will remember how much it was used when I last used it, for whatever. As a result dullness, as evidenced by lack of cutting, can come unexpectedly. These unexpected halts in the flow of work to sharpen are not a pleasant surprise for me. Hence, I want my steel to stay sharp as long as possible and sharpening to be quick.

Obviously my wood removal and sharpening is vastly different from someone settling in to flatten a table top. In this situation sharpening is to be expected during the course of the work and even become a welcome break from strenuous activity. Others have the discipline to sharpen before the tool stops cutting. Hence, you may find what follows irrelevant for your work.

My equipment and materials attributes

I have a bench grinder with a wheel suited to sharpening tool steels (that’s tool steel, not necessarily HSS), cast iron plates and an assortment of diamond paste, fixed diamond plates of various grits, strop and an assortment of other stones that I find to slow for further consideration.
The bench grinder is the fastest way to remove metal but it is risky removing metal to the edge for this fast removal may leave the edge not straight.

Diamonds on cast iron is the fastest way to remove metal at the edge whilst keeping the edge straight. But, diamonds embed in the tool and can be transferred to a subsequent finer diamond plate, if finer grits are employed.
Fixed diamond plates cut faster than many stones but not as fast as the charged cast iron. They do not transfer diamond particles in my experinece.
A strop is good for removing burrs and refining an edge.

The question becomes how to best use what I have in the most effective way. What follows is what I have been doing on the past few projects- chisles, planes and spoke shaves.

1. Hollow grind as needed to a point near the edge but without breeching the edge. This step removes bulk metal fast leaving little metal to be removed by the slower sharpening techniques to follow.
2. Sharpen edge on the cast iron plate with 15 micron paste. This set up cuts amazing fast and will sharpen a blade that is quite dull in a time that does not try my patience. The scratch pattern is similar to a “fine” fixed diamond stone but the cut is much quicker.
3. Refine edge on strop. Mr. Weaver suggests modest pressure on the tool and indeed this works well.

The picture shows the cast iron plate, syringe of paste(a lifetime supply), Strop, and a container of WD40 for the plate lubricant. It should be obvious that this equipment is cheap.

I find the result fine for what I do. Personally, I have been over sharpening, ending with 1 micron diamond in the past. A highly refined plane blade edge after a few feet of planing is duller than what my current procedure starts out so I see little use for my needs of sharpening beyond what is described above.

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