It's prolly a BSP standard, since they used that for other pipe threadings. 37-degree flare appears to be a JIC (Joint Industry Council) fitting, not JIS (Japanese Industrial Standard) -- which latter uses a 30-degree taper with BSP threading.

Not clear if you mean "soft lines" as in rubber lines with attached end-fittings or workable metal; just don't use copper tubing for the latter -- vibration work-hardens it, causing it to crack eventually. Cupronickel (e.g. Cunifer™) would be suitable, typically supplied for brake lines.