Chuck TV Intersect Cube DIY working model

Step 4 Make the Base Plate

1. Cut 1/2 inch plywood into a 9 inch diameter circle.  Cut aluminum flashing sheet stock material into a 9 inch diameter circle. Trim the outside edges with aluminum tape, see photo.  Apply Goop to the plywood top surface and glue the aluminum 9 inch disk in place.

2. IMPORTANT: Next determine where on the disk to drill the 3, 3/16 inch holes for the rubber grommet screws.  The 3 rubber grommets at all located on a "bolt circle" centered at the motor drive shaft, each screw is 120 degrees apart on that bolt circle. The 3 rubber grommets attach the cylinder to the base plate by squeezing against the inside wall of the the glass cylinder at three locations 120 degrees apart.  The squeeze at each locations tends to even out doing a nice job centering the cylinder around the motor drive shaft.  Warning - it is possible to get too much squeeze which can crack the glass.

To help assure the rubber grommet screws are located so as to give the correct squeeze against the cylinder, carefully measure the inside diameter (ID) of the glass cylinder, and the outside diameter of the rubber grommets (OD).  We want the bolt circle to be large enough to assure the cylinder compresses the grommets just a little bit (see photo) when it is installed.  Calculate the bolt circle (BC) using the below formula.

BC = (ID-OD) + 2 mm.

For example, if ID = 83 mm, OD =14 mm, then

72 mm Bolt Circle = (83-14) + 3

I recommend testing this bolt circle by drilling three holes at that BC in a scrap piece of wood to verify correct squeeze.  See photo for how to assemble the 3 grommet & 8-32 thd, 1.5 inch long screws .

If  the fit is good, then drill the real base plate the same way, else adjust as needed..

3.  After the Goop cures, make the locations for the drilled holes in the disk as shown in the Drill Pattern PDF.  The PDF is a full size template, so be sure to select NONE for Page Scaling when you print it out.

4. Note that if you're just making the "simple controller" you do not have to drill the touch sensor wire hole (but there is no harm done if you do drill it.  The touch sensor 1/4"  diameter hole needs to a drilled at a distance equal to 1/2 the outside diameter of the glass cylinder from the center of the base plate.

5.  When drilling the holes, start with a drill bit no larger than 1/8 inch diameter,  and then gradually enlarge the holes from there as needed.  If you try to drill too large a hole all at once, the drill bit will likely snag on the sheet aluminum and make a mess of things.

6.  With all the holes drilled, install the 1/4-20 T-nuts into the wood side of the base plate and use a hammer to seat them fully.  Thread the 3, 1/4-20 2/1/2 inch long hex head bolts into the T-nuts. You want just a few threads sticking out above the aluminum side of the base plate - install an acorn nut on each of the threads.  Adjust the amount each bolt is screwed in so the base plate sits level, then tighten the acorn nuts.

7. You can now install the three grommet mount screws.