In the last post, I left off with the pieces needed for the Roubo Panel Gauge. You see here the walnut for the body resting on the cherry for the arm.
Here is a shot of the end of the arm. I decided on a 5 degree taper for each side of the arm (10 deg total). I don’t have a good reason for 10 degrees other than many people in chair making use 6 degrees and some use 12 degrees, so rather than debate who is right, I took the political position and went for the middle ground. I don’t remember the exact dimensions of the arm, but it is close to 1 inch square and 20 inches long.
Tapered mortises are more difficult to layout than rectangular ones. I marked the first line, then used the actual bar to determine the location of the second one. I suggest you make the mortise a little tighter than you think you should. It is easier to open the mortise up a little than to close it.
With the tapered hole marked out (see the white pencil marks) I used a mortise chisel to chop out parallel mortises. The middle was then easily removed. I considered using a drill to define the mortise, but I remembered the wise words of Mr Robert Wearing that drilling does not make mortising any easier or more accurate. He sure was right. Just go at it with a chisel and don’t be scared.
The tapered arm fit perfectly the first time I tried the fit. Yeah, right. I pared down to the line with a super sharp bench chisel and fine tuned the fit several times to get it right. The bar had a tendency to seat further on one side of the body, making the gauge look like a mess. Shaving tiny slivers of wood here and there did the trick to level the arm out. How did I know where to remove slivers of wood? Move the arm around in the mortise with some force. Areas that rub will show a little burnishing. Remove the burnished areas from the mortise to get more consistent contact.
This was a good time to shape the curve of the body. Notice the use of the leg vise to hold the body flush with the bench top for drawing the curvature. I don’t deal with full-sized prints.
I sawed the body to rough shape and screwed in a 1/4 inch threaded insert at the top center. These inserts are really simple to install and function better than a machine screw threaded directly into wood. I faired the curves and rounded the profile with my new Lie Nielsen spokeshave – it is a wonderful tool.
The body of the gauge gets a rabbet at the bottom of one side. This creates the reference surfaces of the gauge, so do your level best to make the rabbet parallel to the body in width and depth. A good marking gauge helps guide the final endpoints of the rabbet – don’t depend on stops built into the plane. That rabbet completes the body.
It’s time to add some flare to the gauge. In the top of the arm I plowed a 3/8 inch wide groove to house a piece of brass. The brass was 3/8 inch wide and 1/4 inch thick. This is a functional upgrade as well as aesthetic. The arm is locked in place by a screw in the top of the body. That screw would chew up the wooden arm if left unprotected. The brass was epoxied into the groove and later sanded to clean it all up.
The pencil holder is very sophisticated. I drilled a vertical hole for the pencil that was 1.5 inches from the end of the arm. Closer to the end of the arm I drilled a perpendicular hole for a screw that will be used to tighten the grip on the pencil. To make the grip more effective, I sawed a kerf through the end of the arm into the pencil hole.
The perpendicular hole received another threaded insert, but this one was considerably smaller (Number 8). To get the insert in straight, I used a No 8 screw from the backside and manipulated it while driving with the screwdriver. Getting the threaded inserts straight in the hole is the closest thing to a challenge in the process.
Insert a General pencil (premium pencil made in the USA) and give your new gauge a trial run. I’m really happy with the fit and feel of mine. The brass in the arm gives it surprising heft and a classy look.
I finished my gauge with one coat of Boiled Lindseed Oil and one coat of wax. I may go back to using wax more often rather than 6 to 8 coats of oil. It is fast, easy, and looks great. The only offense is the smell of the wax, but it fades after a few days.
There are a few take-aways from this build.
- Read old woodworking related texts when you can. They are full of ideas that are waiting to be rediscovered and put back into practice.
- Starting with your current project(s), build everything to the best of your ability. This includes fixtures and tools for the shop. Always do your best and your best will improve.
- If you are new to designing your own projects, a good place to start is with small things. You can either succeed or fail quickly and try again.
- Complete a project from time to time to prove that you can see one through to the end.