Material: Brass Bar Stock, 12.7mm (1/2") Square, 24mm long
Finished Weight: ~11.3 grams (will need verified)
- Cut a piece of brass bar stock 25mm (1 inch)
- Mount the brass bar stock in a 4-jaw chuck on a lathe centered on the nozzle point (4mm in from 1 edge, centered on the other) leaving a machinable 12.5mm length exposed
- Turn the (to be threaded) nozzle top to 8mm OD for a length of 12.5mm.
- Turn the nozzle top to 6.5mm OD for a length of 3.75mm
- Drill out the center of the nozzle (heat chamber) with a 3.5mm drill bit for a (initial) depth of 22mm
- Mount in a 3 jaw chuck holding by the nozzle top
- Leaving the heater block section 8.5mm long, turn the remainder (to be nozzle tip) down to max 8mm (7.5mm looks nice)
- Turn the nozzle tip: starting 1mm in from the heater block, machine at a 60 deg offset moving towards the tip, until the Machine the nozzle tip to the desired profile leaving the heater block section 8.5mm thick. Total length should be ~24mm
- Drill the nozzle orifice to 1mm depth 0.33mm or 0.5mm ID
- Remove from lathe and finish drill (3.5mm) the heat chamber to total length - 0.5mm
- Thread the nozzle to M8 x 1.25 (5/16-24) up to the shoulder of the heater section
- Using a 6.147mm (size C) drill bit, drill the heater resistor hole through the heater block section. The remaining brass, between this hole and the edge opposite of the melt chamber, should be 0.5mm (0.020 +-0.002) thick. Lindsay: Heat chamber is 3.5mm thick and 4mm in so side of heat chamber is 4+(3.5/2) = 5.75mm (~6) but block is only 12.7mm wide leaving only 12.7-5.75mm = <7mm for heater hole.., if drill 6.35mm hole only allows bugger all on sides = 0.65/2= 0.325mm!.. even drilling 6.1mm still only leaves <0.5mm so.. either way we drill at midpoint between heat chamber & side = 3.5mm in..
- Drill the thermistor hole