This adjuster adds accurate, repeatable adjustment to your jigs and fences. It uses a ¼” -20 bolt and a scale to enable accuracy as small as 0.001″. The adjuster itself is very easy to make from commonly available parts. How you mount it and use it will depend on what you are adjusting. It is versatile enough for just about anything, including accurately positioning a router or table saw fence.
This particular adjuster is made from a short block of oak and a few pieces of hardware from my local hardware store.
Adjuster with router table
Adjuster with drill press
Making the Adjuster
Cut the piece of wood for your adjuster a bit longer than the finished size; you can trim it up later.
Drill a 25/64″ hole in the wood where you want the adjustment screw located and press the coupling nut into it.
Position the two wheels onto the bolt and secure them in place with one of the nuts.
Thread the bolt through the coupling nut and position the o-ring on the end opposite the wheels.
Screw the second nut onto the bolt so that it is very snug against the o-ring. This pulls the threads of the bolt up against the threads of the coupling nut to provide some resistance when turning the knob. It also reduces backlash.
Add the cap nut on the end of the bolt. This is used as a bearing surface against your jig.
Cut a piece of Plexiglas to size.
Drill a hole in one end of the Plexiglas to accommodate the screw and scribe a line on the underside down the centre with a sharp knife.
Drill a pilot hole in the wood in-line with the bolt and attach the Plexiglas.
Make a copy of the scale and wrap it around the inner wheel. The scale lines at each end must match-up when they overlap. If they don’t, either sand the wheel down slightly or wrap tape around the wheel to change the size until the scale lines-up.
Using the Adjuster
Once the adjuster is made, you can position it as required. Each mark on the scale represents 0.001″ of travel. To use it, set your jig or fence at roughly the position you want and snuggly place the end of the adjuster up against it. Make a test cut and measure your result. Use the adjuster to make the necessary changes until the cut is exactly what you need.