Hello Fellow Neanderthals,
When it comes to sharpening chisels and plane blades, some of you have the ability to will a blade into submission using only your mind so that it instantly becomes scary sharp with a square edge. I do not share such abilities even after employing various chants and magic spells. I use a Vertitas Mk11 guide to achieve consistent results. But I’ve had a problem getting consistent square edges with my grinder for the primary bevel, even with an updated wheel and tool rest. So when I use the Veritas guide afterwords, the bevel might be a bit different than the primary bevel from the grinder.
While taking a break from watching videos of kittens and puppies, I came across a Youtube video from Taylor Toolworks that some of you might have seen. It describes a 5” or 6” acrylic disc that you use to attach Cubitron adhesive sandpaper and mount in your drill press. He details several uses, but the one that caught my attention was grinding the primary bevel on blades. The kit is inexpensive so I decided to give it a try. Here’s the link to the video: https://youtu.be/1QmDvJbfM-8
The video describes building a jig to hold the blade at the desired angle to the bottom of the disc, which I did. This works quite well, but there can still be a slight difference between that bevel and the one that is honed with the Veritas guide. So, I started thinking about a way to use the guide throughout the whole process, and it came to me in the middle of the night, which seems to be where I get my best ideas.
Instead of using the bottom of the disc as described, I use the top of the disc so that the primary bevel can be ground while using the Veritas guide set at 25 degrees. The guide needs to sit on a block of wood to elevate it slightly off the table to produce the desired angle, and that angle is dependent on how high the guide sits in relation to the disc. After some trial and error, I decided on a tad less than 25 degrees (not 2 tads), for reasons I’ll explain. The guide is set for the standard angle, not the microbevel angle. I first tried 80 grit but ended up liking 180 grit for a smoother finish. Just be careful of heat buildup; I used a slow speed on my drill press and a cup of cold water to keep the blade cool.
The process is very quick. Once finished, I move to my 1000 grit Diamond stone for a few passes while the guide is still set at 25 degrees. Since the guide is now sitting flat on the stone, it produces a true 25 degree secondary bevel. And, that bevel is square to the primary bevel. I clean that up with a few passes on my Shapton 6000 grit stone. Finally, I adjust the guide into the microbevel position and move to my 16000 grit Shapton for that task. Remove the blade from the guide, polish off the burr on the back, and life is good.
Of course, the blade angle for the primary bevel needs to be repeatable. It is dependent on the height of the table in relation to the disc. My solution was to glue a small block of wood to the original wood block. While the disc is spinning, I slowly lowered the block onto the disc until the assembly sat flush on the table, leaving a small dado for reference. To set the proper table height in the future, I just need to adjust the table height so that the dado is just clear from the disc. The photo probably explains this better.
The photos show my results with one of my beater chisels, but I have since used this process on my good set. I now don’t have any excuses for putting off re-grinding the primary bevel when the secondary bevel gets too large for quick touch ups. Now, back to more kitten videos…
Reply With Quote