Hey Doug,
You really need clearance underneath to use these under-table mounts. The mount itself is 4 1/2 inches long and with the DZ1000 add another 1 inch for adequate clearance for the motor and electrical connection.
For about $3 a piece, which includes the wood screws to secure the assembly to the underneath of the top, the two 4-40 machine screws and nuts to secure the fulcrum, and if I remember correctly, an adequate length of music wire. I usually fabricate a lot of my own stuff, but for $3 to gather all this stuff and prototype and then build 7 of these made no fiscal or time sense to me. You will see by the pictures they are sturdy and offer slight adjustment in place.
Because of my experience with the Tortoise switch motors, make a template (tempered 1/4 inch Masonite, acrylic, aluminum) to get everything lined up for drilling underneath. Use the bracket itself, with the centered DZ mounted, to layout the template locating the slotted mounting holes (2) and interpolate the location of the one music wire hole clearance (5/16 inch).
I block the switch points to hold a center set. Then determine which side of the switch throw bar to use. The hole down through the throw bar is your guide. Using a small enough but long enough drill bit, drill down straight through the table. I use a piece of stiff wire to locate the hole underneath and mark it clearly. I use a 5/16 brad point drill bit with a stop collar securely fastened to the bit and properly gauged to the thickness of the deck and any roadbed material. Very important! Too long or the stop collar slips, the throw bar is gone! The sharp pointed tip on the brad point bit will center perfectly in your previously drilled pilot hole. I found 5/16 inch is optimum allowing full throw of any manufacturer's switch.
Now I use an appropriate length 5/16 bolt so I can secure the template to the mounting location from underneath through the drilled hole without hitting the throw bar but pulling the template tightly to underside of the deck. Centered on location and hands free if you wrap a bit of tape to shim the bolt some. I actually like it so I have to thread the bolt into the wire clearance hole. Turn the template so the mounting screws are perpendicular to the through switch rails and drill pilot holes for the mounting screws.
Works for me. You may develop your own methods.
