This instructable shows a simple way to raise and lower a plunge router inside a router table.
I found it difficult to set the height in my router table due to the resistance of the spring. When released, the plunge router spring would extend to its maximum, removing any kind of adjustment that had been previously made.
This instructable uses simple materials from a hardware store, and some fairly basic hand/power tools.
NOTE: I have my router table screwed to a piece of wood. The height adjuster may lift your whole router table instead of just the router if you don't have the table screwed to a piece of wood. I haven't tried it with the table not attached to a piece of wood.
NOTE: This design may block the vents of your router, or may interfere with speed knobs, etc that are on the bottom of your router. If you use this design, be sure that you are not going to damage your router by putting pressure on its base, or blocking its air vents. For prolonged periods of running the router, it would be a good idea to remove the height adjuster. Additional holes in the pipe flange may also provide adequate ventilation.
5/16” carriage (stove) bolt (1) or hex bolt. Other similar sizes may be used if you have them on hand.
5/16” nut (1)
5/16” washers (2)
1/2” iron pipe coupler (1) from plumbing supply area
1/2” iron pipe flange (1)
Block of wood approx 3” x 3” x 1/2” thick, or a little thicker
Magic marker or other for marking the bolt
Install the router in the router table, and install a tall router bit which you would like to have control over height. Lower the plunge router all the way by releasing its handle, allowing the spring to extend. If necessary, loosen the collet on the router bit and extend it so that its tip is just above the top of the table where it would begin to cut wood. If needed, raise the plunge portion also, and latch it. Measure the distance between the bottom of the router and the workbench, or surface where the router will be used. This is your minimum height.
NOTE: I have my router screwed to a piece of wood. The height adjuster may lift your whole router table instead of just the router if you don't have the table screwed to a piece of wood.
Next, push the plunge router all the way in, and latch it. The router bit should be sticking out its maximum from the top of the table. Measure the distance again from the bottom of the router to the benchtop or piece of wood. This is your maximum height. The first measurement and the second measurement tell you the length of travel that you want