I thought the hole was 0.2mm? At least the Petromax replaceable 300cp jets are. They then go up to 0.25 mm for 500 cp. I can drill 0.2mm holes quite successfully in Brass never tried a 0.15mm hole! Those bits must be sooooo fragile as the 0.20mm ones are a git to use! Drilling 0.25mm for 500 cp must be a breeze compared!