Grindstones for Old Chisels

[RichColvin]

Today I experienced an interesting find relative to the correct grindstone to use for sharpening for an old chisel.  The chisel of note is an old Stanley 1 1/2" wide chisel I inherited from my grandfather.  He passed away in 1985.  So I know the chisel is over 40 years old, but it is probably closer to 75+.

All that matters as it says that this chisel is definitely made from high carbon steel.

I love using this chisel for all the nostalgia reasons, but also because it works so well.  Recently though, I nicked the blade when using it on old wood (I hit a hidden nail). 

The process I wanted to follow was:

• Re-profile the ground surface, removing the nick, using the coarse diamond wheel (DC-250).
• Sharpen the chisel using the fine diamond wheel (DF-250).
• Clean up the grinds using the extra fine diamond wheel (DE-250).
• Hone the edge using red rouge on a paper wheel.
• Hone the edge using jeweler's rouge on a paper wheel.

What I found was that step 1 was taking a LONG time.  So, I switched over to the tried-and-true process:

• True the traditional grindstone (SG-250), and then re-profile the ground surface, removing the nick.
• Re-grade the traditional grindstone to around 250 grit, and then clean up the surface scratches.
• Re-grade the traditional grindstone to around 1000 grit, and continue cleaning up the surface scratches.
• Do a final clean-up of the cutting edge using the Japanese waterstone (SJ-250).
• Hone the edge using red rouge on a paper wheel.
• Hone the edge using jeweler's rouge on a paper wheel.

I found that the 2nd process took about 30 minutes, and I achieved the desired sharpness on my chisel.  After applying camellia oil, this chisel is ready for business again.

I was surprised at the difference I saw in the time required.  It reinforces what Ken has said so many times:  the original grindstone is not dead.

[Ken S]

Rich,

I recall something in one of the recent online classes. I believe it was Wolfgang who demonstrated using the support bar (very close to the grinding wheel, held under horizontal support bar). If using the SG, the SG should be freshly trued. The chisel should be pushed in at a 90° angle.

The nick should be ground away, the bevel should be reestablished and sharpened using the same coarse stone, either the SG or DC, depending on what you have.

Do not switch to a finer grit until basic sharpness is reestablished. At that point, switch to a finer stone. Do not omit this step, even if you intend to use the SJ. I finish up with the leather honing wheel and PA-70. At this point, feel free to "season to taste". Depending on your intended use and species of wood, you may want to refine this further.

Ken

[tgbto]

Rich,

That is an interesting observation. I do not have a lot of experience with woodworking tools, but I have noticed something similar with relatively hard knives (ca. HRC 63). The diamond wheel kind of cuts better, but as I am using very light pressure, it seems to be faster overall with a coarse-graded SG (graded using a 80 grit diamond lapping plate).

As the scratch pattern is also more homogeneous with the SG, it takes less time to smooth with higher grits, so I get the desired finish in much less time when taking the SG way.

I now keep the diamond stones for carbide tools, which I don't sharpen often. They're kind of a luxury display item

Nick.