Another entry from my apprentice John who continues on the Trestle Table project when not on the road.
So I was in the check out at the market with a live lobster in a bag and a half gallon of gin. I looked at the check out person and said “one of us isn’t going to make it through the night”. She gave me a look. Yesterday, I got the same look from my wife. I was looking at a plane iron with a magnifying glass talking to myself about 1,000 grit scratches when I noticed she was looking at me.
Let me explain. I was helping at a recent class being taught by Chris and Tom Lie-Nielsen at Marc Adams School of woodworking. Chris was talking about sharpening and said that sharpening is really about seeing. As he went through the various grit stones he was using he held the iron up to the light and moved it around to see the edge. He said he could still see some 1,000 grit scratches in it.
I thought about that and decided to really try to concentrate on seeing the edge as I sharpen. To help see the difference in the scratches I changed stroke direction when I changed grits. I tilted the edge to the light and I could really see coarse scratches left in the iron after using the 1,000 grit stone. It’s like I snatched the jewelers loop out of the Master’s hand and can now sharpen my own plane. These scratches needed to come out on the 4,000 grit stone before going to the 8,000 for polish. In the past I would not have taken the time to concentrate on the edge and would have switched grits sooner resulting in an inferior polish on the edge. It also causes sharpening to take longer since I would have been polishing 1,000 grit scratches instead of polishing 4,000 grit scratches, which is a lot easier to do.
The sequence to sharpening is to take the tool from a grinder to a 1,000 grit stone for edge shaping. Stay on the 1,000 as long as it takes to get a wire edge on the back side of the tool (the back side must also be flat and polished. That means going through the same sequence but you only need to do this once). Then to the 4,000 grit, which is used to remove the 1,000 grit scratches and then to polish on an 8,000. That is it. I am sharpening two tools for the first time today. It took four strokes to get a wire edge on the 1,000 grit, approx six strokes on the 4,000 and between 3 and 6 on the 8,000. Then turn the iron over and carefully slide the wire edge onto the 8,000 grit stone to remove the wire edge.
So if you want to make an impression try the lobster and gin trick, or grab a magnifying glass and see if you can see the scratches.