21


Motor mount for 23mm diameter Escap motor
Preparation
Remove the motor from the original PT holder; cut from wire hole to base to free wires, then push down on motor to extract from the PVC pipe.
If using an external controller, cut wires to around 16cm and terminate wires with the chosen plug (I use USB 1.1 type A).
Notes
Glue takes eight hours to cure, so glue and mark foamed PVC sheets at least that time before cutting.
When drilling the foamed PVC sheet, place scrap wood/MDF underneath and drill slowly all the way through, backing out drill to clear swarf.
motor mount template
Tools
Wide masking tape
Ruler, compass, protractor, pencil
Stanley knife
Pillar drill
Holesaws: 70mm, 23mm
Drill bits: 4mm, 10mm
7mm Allen key
Pliers or vice.
Materials
2 A4 (297mm x 210mm) 5mm thick foamed PVC sheet
PVC weld glue
3 x M4 10x10mm anti-vibration mounts
3 x M4 nylon washers
3 x M4 nylon nuts
3 9.5mm plug grommets
5cm of brass 11/32" tube
3 x 10mm panel covers
Construction
•Tape PVC sheets together, draw a line along the long axis, 97mm from one side, and cut.
•Glue the two 97mm strips together, and leave to bond. tape the other two strips together, and cover the top surfaces of both pairs with masking tape.
•On the wider pair, mark another 97mm line on the wide edge.
•Find the centre points of the squares, and prick with the compass point.
•Draw six pairs of concentric circles of 12.5mm and 35mm radius in the six squares.
•On the glued strip, Mark three lines, radiating from the centres, 120 degrees apart.
•Mark points 25mm along the lines, prick with compass point. Do this in all three squares.  Mark these points for the 10mm drill.
•On the unglued (wider) strip do the same for two of the three squares.  Mark the points for the 4mm drill.
  
Leave glued piece to cure.
PT_Motor_mount_template.png
Drill the 25mm radius points with the 4 and 10mm drill
Drill the 70mm radius circles to a depth of 2mm (to help locate saw for final cut).
Drill the 23mm holes through.
Drill the 70mm holes through, carefully extracting the foamed PVC toruses from the holesaw after each cut.
Sand smooth the edges, taking care not to enlarge inner hole


Check fit of mounts in subchassis, and bottom layer onto mounts
Loosely fit all M4 nuts, washers onto bottom layer with spare M4 bolts.
Crimp end of brass tube around a 7mm allen key, to form a thin-walled socket for the M4 nuts inside the foam layers.
Glue top (10mm thick, 10mm holes) layer onto bottom (5mm thick, 4mm holes).
When dry, check fit of motor in central hole; the top of the motor should be flush with the top of the mount.
If loose, then wind insulation tape around until a snug friction fit is achieved.  If all else fails, use an adhesive.