When I started out using more and more handtools for woodworking i noticed that having a shape edge on my tools, all the time, really improved the overall quality of my work. For chisels and plane irons its very hard to maintain a consistent angle while grinding it. So i decided to build my own simple jig to help me with this task.
Step 1: Choosing the Material
Use a rather hard wood for this project since you don't want your jig to deform when clamping a tool firmly.
Step 2: Cutting the Body
Most of the dimensions are not very critical. As a general rule of thumb: Make it shorter than your shortest chisel blade (here about 10cm). Wide enough to accommodate the rollers. Cut the front and back side at the steepest angle intended for grinding. For me that was 45° since i grind most of my tools to 30°.
Step 3: Adding Shoulders for the Rollers
Since I used rather large rollers I needed to add shoulders to the body. Otherwise the body would need to be far too long. Using a table saw with a fence, this is quick and easy.
Step 4: Drilling Holes for Threaded Rod
In order to have a body that can close up perfectly, it is a good idea to drill the holes for the threaded rods at this state of the build. I used M6 threaded rod for the clamping mechanism and used 6.5mm holes respectively.
Step 5: Adding a V Groove to the Block
Two angled cuts at the bottom of the block will later serve as the tool rest. I have also added a similar feature to the top of the jig in order to be used with wider blades. Make sure both don't interfere with the pre drilled holes.
Step 6: Cut the Body in Half
Step 7: Completing the Tool Rest
Now that the body is in two haves, the V groves can be cut open using the tablesaw. Here it is important to have the depth of the cut adjusted precisely.
Step 8: Adding Rollers and Threaded Rods
By adding the rollers to ride on the sand paper and the threaded rods together with some wing nuts, the build is completed.
Step 9: The Finished Jig
Here you have it, the final jig ready to use. I've used this contraption for half a year now and so far I had no issues with it. For me it worked best using the "scary sharp method" ( http://primeshop.com/access/woodwork/scarysharp/ ) with sandpaper sprayglued on glass.