85 POWER ROUTER RAISER
Powered by an old automotive seat adjuster motor.
SHOP OWNER: Scott Amman
LOCATION: Milford, MI
My router (Freud FT2000) mounts underneath the extension table of my tablesaw. I'm tired of always having to reach under the table to make height adjustments to the router. There are numerous aftermarket devices out there that allow you to adjust the height of the router from above the table manually, but I thought I'd do them one better and add some power to the height adjustment concept using an old seat adjuster motor from an automobile. The seat adjuster motor works nice since it has a lead screw integrated into the assembly. It's quite unlikely that someone would find the exact seat motor assembly I've used here, but other motor assemblies could be used in a similar fashion with some modifications.
Shown in Figure1 are the main components of the system. For power, I used a 12-volt power supply from Radio Shack that has a current over-limit breaker that will trip if the current draw is too high. This is important in case the system ever binds and draws excessive current, thus frying the motor and/or supply. The voltage to the motor is controlled with a double-pole double-throw switch with a neutral mid position. When the switch is in the mid position, no voltage is applied to the motor. When it's in the upper position, +12 volts is applied, thus, raising the router. In the lower position, the polarity is reversed and the router is lowered. I've also incorporated an additional 110-volt outlet in the switch box that the power supply plugs into. This isn't absolutely necessary, since the supply can be plugged into any existing outlet.
Figure 2 shows a close-up of the router and height adjuster assembly with the main components identified. The screw assembly is made up of the lead screw and nut assembly. The nut assembly required some minor fabrication work to attach it to the router base plate, but it was nothing too difficult. Also, you'll see two micro-switches that I've used as limit switches. These serve the purpose of switching off the adjuster when it's reached its limit of travel. I've mounted these switches to small maple blocks with holes drilled so that they can be put on to a 3/8" carriage bolt and adjustments made with the nuts you see on the bolt. The limit arm is just an L-bracket mounted to some existing bolts on the motor.
Figure 3 shows the top and bottom view of how I mounted the seat adjuster motor to the router. I used a couple of pieces of angle iron bolted together at 90° and a mending plate (I twisted the plate since mounting positions were at 90° to one-another) that attaches to the existing height stop for additional support. I had to do some grinding and cutting to get the bottom-most piece of angle iron to bolt up to the existing screws that hold the FT2000's metal housing to the plastic housing.
Finally, Figure 4 shows the entire system installed in the extension table of my Unisaw. I should mention that the springs were removed from the router. The handles were also removed to facilitate easing the removal of the router and base plate from the extension table. The switch/outlet box you see to the left is what I use to turn on and off the router.
I've found this set-up to work quite well. It's pretty easy to jog the DPDT switch to get the router bit to the right height and is a whole lot easier than adjusting the height adjustment knob from beneath the table.. . . Scott Amman
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