MATE Building Instructions - Page 9

 

NEEDLE VALVE ASSEMBLY

NUT (7-5)

  1. Centre 1/4" hex brass stock and extend 6mm from the jaws. Face end, centre-drill and drill with ascending drills to Ø2.6mm x 15mm deep.
  2. Use high spindle speed, back drill out several times to clear. Tap M3 x .5mm to full depth. Finish turn shoulder to Ø6mm x 1mm long and part off with 1.6mm blade at 2.5mm from faced end.

COLLET (7-6)

  1. Extend stock a further 16mm from jaws and face end as required to give previously threaded bore 10mm deep. Finish turn Ø5mm to jaws.
  2. Part off at 13mm from faced end. Centre collet in chuck and extend 3mm. Centre-drill and drill Ø1.6mm through to bore. Chamfer end 45 x .5mm wide. Slit by hand with a fine Zona saw blade, or use a fine slitting- saw in the mill.

SPRAYBAR (7-4)

  1. Centre remaining brass stock and extend 20mm from jaws. Face end, centre-drill and bring up tailstock support. Finish turn to Ø3mm x 19mm long and thread M3 x .5mm x 11 mm long. Use shoulder nut as a gauge for a good, close thread and finish with Brasso. Drill the centre hole 17mm deep with a new Ø1.6mm twist drill. Run at highest possible speed and back out several times to clear.
  2. Remove from chuck, measure total length, re-centre on hex and part-off surplus material to leave at 26.5mm overall. Re-centre on Ø3mm (protect thread) and insert in jaws up to shoulder. Finish turn to Ø3mm x 6mm long, leaving a small bump about Ø4mm, to retain the fuel tubing. Centre-drill and drill the Ø1mm hole right through, using the same speed etc. as before. Counter-bore 1.6mm x 8mm deep.
  3. Clamp spray-bar in machine-vyce and drill a Ø1mm hole, centred over the axis and perpendicular to it, 4mm from the flanged face, through to the bore. Clear any burr raised in the latter.

NEEDLE (7-7)

  1. Centre 1/16" silver steel and extend 3mm from the jaws. Face end, round and polish. Reverse and face off to 48mm long. Drill a 1/16" hole in a piece of scrap material. Clamp this material on the tool rest of a bench grinder, very close to and at an angle of under 5 to the side of the wheel.
  2. Using this as a guide block, grind the end of the silver steel nearly to a point, twisting the stock between the fingers. Try not to burn it, or them. (Use a test piece of silver steel first as a practice run). Then centre in the lathe with minimum overhang and polish the point with #800 paper, being careful not to round it off. Remove and bend the end over as shown.

 

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