How to sharpen my plane iron (with a BESS score)

[WimSpi]

I have a beautiful Stanley No. 5 plane from around 1960. Only the plane iron (lightly sharpened) was not ground accurately. I corrected that on the Tormek T8.

I chose a sharpening angle of 26 degrees. For that, I used the Tormek accessory TE-77 (photo 1). It's important to position the iron correctly in it. I don't use the two small adjustment knobs for corrections. I do it the old-fashioned way: a 90-degree pencil mark just below the cutting edge. This serves as a check to ensure I'm sharpening square. By the way, a good plane should have a bit of play when adjusting the iron (think of an angle of 89 degrees). However, it's important for the cutting edge of a plane iron to be perfectly straight.

I used the following Tormek diamond stones in this order: DC-250 (360 microns), DF-250 (600 microns), DE-250 (1200 microns), and finally the SJ-250 (4000 microns).

First, I sharpened the back of the blade (the flat side). It must be perfectly flat; otherwise, you won't achieve the desired sharpness and may also get scratches on the planed surface. I sharpened this flat on the sides of the Tormek stones mentioned above.

Next is the bevel of the plane iron. Plane irons are often sharpened in daily use because they tend to dull relatively quickly. Therefore, you don't remove more steel than necessary. You can see this on photo 2, on the right side of the bevel. The angle is correct at the bevel, but not at the top of the bevel. From our sharpening perspective, it may not look perfect, but it's not a problem for a carpenter's use. It will be corrected in the next sharpening session, resulting in a nice, crisp bevel.

I never sharpen a micro bevel on a plane iron. We don't know that in the Netherlands. I find the discussion about that more theoretical than practical.

After sharpening the bevel on all the stones, the iron looks sharp (photo 3). It easily cut the hair on my arm. The BESS score ranged from 81 to 99 (photo 4). It's not consistent, but more than sufficient for practical use, based on my 53 years of working and sharpening experience with carpentry tools.

However, I ran the plane iron over a leather wheel with 0.25 micron diamond paste. This resulted in a stable BESS score of 61. I'm very satisfied with this level of sharpness (photo 5).

Afterward, I need to slightly round the edges on both sides of the bevel, so as not to create a "groove" in the wood (photo 6). I do this freehand with the DF-250.

(I hope the translation is a bit clear)

[Ken S]

Wim, a well written, informative post.
Ken