One question from a reader prompts me to illustrate the process I use to prepare hollow mortise chisels before I even approach the benchtop mortiser.The process is called “tuning a hollow chisel”; it prepares the chisel for efficient cutting of the mortise, and eases penetration into the wood while minimizing burn marks. This results in smoother mortise walls, faster cutting, and better chip ejection while keeping the chisel cooler. So far I have not had to sharpen any of the drilling bits on any of the chisels.
In this photo you see the hollow chisel as received. The grinder marks are plainly visible:
Just like a bench chisel, the sides of the chisel should be lapped using either sandpaper or, as I show here, with sharpening stones. Following preliminary lapping on the 1,000-grit stone, I continue with the 6,000-grit or finer stone:
In this next photo you see how the steel begins to shine, and the tool marks have disappeared near the cutting edges – not quite ready for work, the chisel is getting close to being ready to cut:
Next I use a diamond-covered abrasive cone, to sharpen the inside surfaces of the tip of the chisel. The cone holder is part of a set available from various sources:
Careful inspection is a must, before using the chisel. Look carefully at the inside surfaces, to make sure the cone has left smooth, shiny surfaces:
Yup, that is the BenchCrafted tee shirt. And it is a shameless plug for the company that makes, along with 11 other winners, the Popular Woodworking magazine’s Best New Tools for 2009, the BenchCrafted Tail Vise. I was the lucky recipient of one tee shirt at the Valley Force conference:
To my friend Jameel Abraham, of BenchCrafted.com, and his brother Fr. John, congratulations for winning the award – it is well deserved!
Disclosure: I am a happy owner of one BenchCrafted tee shirt; I have no commercial or any other interests in BenchCrafted.com. And I love the vises they make.
— Al Navas