The vise chop is one of the few areas where you can add an individual touch to the design of a Roubo workbench, and a Google search can show a whole gamut of different chop styles. For the chop on my Roubo bench, I decided to go for a simple round over which fit the simple aesthetic of the bench while adding a curve to a very rectilinear project.
Before shaping the chop I first needed to trim it to length. I had deliberately left the chop over-long as I did not know exactly what thickness the slab top would end up once flattened. To level the chop I mounted the hardware, and then used an unhandled Hock Tools marking knife to strike a line on the inner-face of the chop, flush to the benchtop. With the final length marked out, I then laid out a curve using the “Roubo” French curves from Sterling Tool Works (let’s be honest, I had to find an opportunity to deploy the Roubo curves on this project didn’t I). Once I had a curve that was pleasing to the eye I marked this on both sides of the chop, and also struck a line at 45 degrees from the top of the chop to the face which fell just outside the arc of the round over. I clamped the chop side-down to the bench top, and cut down the 45 degree line to remove most of the waste before trimming the excess length off the chop.
I am now at the stage of the build when I can use the bench to build the remaining components of the bench. To shape the chop I re-mounted the hardware, and sat on a saw bench, which put the workpiece at a comfortable height. There are many ways to shape a gentle curve, including with rasps or spokeshave. Given that the chop is over 6″ wide, and the round over is largely in end grain, I thought rasps might be a bit much like work. Instead, I worked across the width of the chop with a sharp low-angle block plane. This is a very effective way of working, as the low cutting angle leaves a clean surface on end grain, and removes material in a very controlled manner. I used two (freshly sharpened) block planes for this task – No60 1/2 to remove most of the material, and a No102 for the final finish cuts, although you only really need one providing you stop to resharpen before taking the finish cuts. The technique is essentially to remove the aris left at each side of the previous cut, which increased the number of facets forming the roundover, and simultaneously reduces the size of each facet. Eventually, the facets become so small that they are imperceptible. Skewing the plane, and taking a light cut, reduces the risk of spelching the far side of the workpiece.
If facets really offend you, then following up with a cabinet scraper or sandpaper can smooth the surface – I used a scraper to smooth things out, although I did not try to obliterate all evidence of facets.
Once I was happy with the round over (and this is very much a case of “if it looks good, it is good”), I removed the chop from the mounting hardware and scraped the show surfaces to remove any workshop rash, and chamfered the edges with the Philly Planes chamfer plane. To chamfer the round over I used an Auriou 13 grain rasp, although a spokeshave would also do a good job.
As a final step, I glued the crubber to both surfaces of the leg vise, using contact adhesive and clamping the vise tight together to hold the crubber in place while the glue cured. A sheet of cling film between the vise jaws stops the jaws being stuck together by any squeeze out. Once the glue has cured I will oil the vise chop, and trim the excess crubber. Then it will be onto boring holdfast holes and the planing stop mortise. At this point, completion of the bench is definitely in sight, with only a few weeks’ work left to go.