| day |
notes |
hours |
| 8 |
Finish off trailer ramp bracket drawings with sketches for fabricating channels and send off to Roger Huttlestone with a covering letter. |
|
| 9 |
Move starboard wing to trailer, with Ian McGugan's help. Clear layup table, remove accumulated epoxy spills and re-wax. |
|
| 10 |
Buff up waxed tabletop. Look around for material for resin balance construction. Find some 25mm square aluminium tube for balance beam, 2.5mm ali plate for cup holder, steel brackets for pivot support and old record player pickup arm with ready-made pivot. Sort out some unused nuts and washers from stock and weigh each to check consistency. |
|
| 16 |
Cut front end off pickup arm to equalise tube lengths. |
|
| 17 |
Find, bandsaw and plane up some mahogany from recovered stock for resin balance base and pivot pillar. Holesaw cup platform aluminium plate 64mm diameter to hold small cup. Hacksaw to width for large cup. Find some ali angle for edges, to locate big cup. |
|
| 20 |
Cut and pop-rivet 3 pieces of aluminium angle to cup-holder plate. Chamfer end of balance beam and pop-rivet to cup plate in correct position to retain large cup. Fold up some old lead flashing for balancing weight. Determine pivot position on balance beam and drill for pivot. Cut off blind end of brass locknut securing pivot under beam so it can go home further. Countersink ali button as packing piece. Sand wooden parts. Position, drill & screw brackets to upright. Drill out and cross-drill 2 ali buttons for split-pins to retain pivot bar in brackets. Assemble and check. Look for some long thin machine screws for weight pins; M4 x 50mm seem fine but only 3 in stock; could use more for different batch sizes. |
|
| 21 |
Get 20 off M4 x 50mm hex head machine screws and nuts at Moorhouse Fasteners. |
|
| 22 |
Mark out and drill 4mm holes across balance beam for weight pins; at 60mm right of pivot and at 60mm, 120mm, 180mm, 300mm, 420mm & 600mm left of pivot. Enlarge rear side holes to 12mm to clear a 7mm AF socket. Mark out and step-drill lightening holes every 60mm between weight pin holes. Select straightest M4 x 50mm screws, fit and try out - works OK. |
|
| 31 |
After toying with the notion of a liquid damper for some time, discard that idea on grounds of potential messiness. Measure up and cut ply for air dashpot box. Assemble with woodscrews onto LH end of balance base. Do some geometry checks in CADintosh, then cut thin aluminium sheet to size. Drill offcut of 2.5mm ali plate as mounting arm for damper sheet & pop-rivet on. Find long (about 20mm) 8BA machine screw for an index pin. Drill and fit it to rear of balance beam at extreme left-hand end. Mark out and cut ply for damper box front plate, drill for screws, cut slot for damper mounting arm. Make up a scale in CADintosh, print out and stick onto front of damper box. Pop-rivet damper mounting arm to bottom of balance beam. After a long hunt for the glass-cutter (which hasn't been used since we moved), cut off a small piece of mirror glass, smooth edges with TC file. Cut off piece of broom-handle at 45 degrees. Drill opposite end for woodscrew. Stick mirror piece to angled end with 5-minute epoxy. Mount onto base with woodscrew from underside; align to get good view of scale & index pin. Assemble complete
resin balance
and test - damping is minimal, but otherwise all works fine. |
|
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