Randy Klein
11-25-2008, 2:15 PM
For those who hate sharpening jigs and/or scary sharp, you'll probably want to stop reading now.
I want to share my home made scary sharp jig.
It is a slight change to the jig that Brent Beach has. I'm not going to rehash everything he has written about the use of the jig or the terminology , I'll just explain the differences and what those differences provide. Brent's information can be seen here (http://www3.telus.net/BrentBeach/Sharpen/index.html). For those who haven't visited his site, it's a great read and a fair amount of information.
The main reason I changed anything to Brent's design was that I wanted to be able to camber my jointer and smoother irons. His design, IMO, does not readily allow that. My idea is to camber the jig, so that the iron can be subsquently camberd as well. The problem is that the short jaw in his design is only 1/8" thick, there's not alot of wood there to shape into a camber. The obvious solution is to make the short jaw taller and then camber it.
Here's a pic of two of my jigs with taller short jaws. One is cambered on both tall and short jaw. The other is not.
101954
A taller short jaw is also easier to fine tune; making something 1-1/8" is a lot easier than 1/8".
However, a taller short jaw produces a bigger back bevel, which could be undersireable. The solution is to move the jig off the glass. Here's a pic of the platform. The jig slides on the melamine.
101958
By moving the jig off the glass, a few more design opportunities present themselves. Brent uses slips of different thicknesses to control his second and third microbevels. While this is still a viable option here, I discovered a different way: I changed the thickness of the MDF backer. My first micro bevel is honed on a MDF backer that is a full 3/4". The second micro bevel has a MDF backer that is 3/4" - 1/32" thick. The third has a 3/4" -1/16", or another 1/32" less thick than the second one.
101955
You may be able to see the slight differences in height in this shot.
101956
The changes in MDF here would be equivalent of a 1/32" and 1/16" thick slip, which would be very difficult to make and rather fragile. These smaller changes allow for microbevels that are closer to each other and thus require less honing to get rid of them at the next honing.
Here's a pic of my jig to properly set the extension. It ensures a square iron to both the tall and short jaw and a precise extension. If you want to change the extension, you just swap out a different spacer.
101960
I also made one more change that has really helped out. I added a thin piece of leather between the jaws. This leather provides a death grip on the iron and virtually guarantees the iron won't slip during honing. You just have to account for it's thickness when designing the jaw's height.
So, the cambered and taller jig I have shown does my smoothing and jointing irons. The lower jig is used for my low angle, bevel up LV jack iron (profiled for shooting). The iron was short, so I had to make a shorter jig. I haven't made a chisel jig yet, but I can still free hand hone those until I do.
A big thanks to Brent and his research. These jigs are relatively easy to make and mine came from the scrap pile, so they were free.
Feel free to ask any questions.
I want to share my home made scary sharp jig.
It is a slight change to the jig that Brent Beach has. I'm not going to rehash everything he has written about the use of the jig or the terminology , I'll just explain the differences and what those differences provide. Brent's information can be seen here (http://www3.telus.net/BrentBeach/Sharpen/index.html). For those who haven't visited his site, it's a great read and a fair amount of information.
The main reason I changed anything to Brent's design was that I wanted to be able to camber my jointer and smoother irons. His design, IMO, does not readily allow that. My idea is to camber the jig, so that the iron can be subsquently camberd as well. The problem is that the short jaw in his design is only 1/8" thick, there's not alot of wood there to shape into a camber. The obvious solution is to make the short jaw taller and then camber it.
Here's a pic of two of my jigs with taller short jaws. One is cambered on both tall and short jaw. The other is not.
101954
A taller short jaw is also easier to fine tune; making something 1-1/8" is a lot easier than 1/8".
However, a taller short jaw produces a bigger back bevel, which could be undersireable. The solution is to move the jig off the glass. Here's a pic of the platform. The jig slides on the melamine.
101958
By moving the jig off the glass, a few more design opportunities present themselves. Brent uses slips of different thicknesses to control his second and third microbevels. While this is still a viable option here, I discovered a different way: I changed the thickness of the MDF backer. My first micro bevel is honed on a MDF backer that is a full 3/4". The second micro bevel has a MDF backer that is 3/4" - 1/32" thick. The third has a 3/4" -1/16", or another 1/32" less thick than the second one.
101955
You may be able to see the slight differences in height in this shot.
101956
The changes in MDF here would be equivalent of a 1/32" and 1/16" thick slip, which would be very difficult to make and rather fragile. These smaller changes allow for microbevels that are closer to each other and thus require less honing to get rid of them at the next honing.
Here's a pic of my jig to properly set the extension. It ensures a square iron to both the tall and short jaw and a precise extension. If you want to change the extension, you just swap out a different spacer.
101960
I also made one more change that has really helped out. I added a thin piece of leather between the jaws. This leather provides a death grip on the iron and virtually guarantees the iron won't slip during honing. You just have to account for it's thickness when designing the jaw's height.
So, the cambered and taller jig I have shown does my smoothing and jointing irons. The lower jig is used for my low angle, bevel up LV jack iron (profiled for shooting). The iron was short, so I had to make a shorter jig. I haven't made a chisel jig yet, but I can still free hand hone those until I do.
A big thanks to Brent and his research. These jigs are relatively easy to make and mine came from the scrap pile, so they were free.
Feel free to ask any questions.