Copymaster 3D 500 bed levelling knobs

Bed levelling during the start of a print is very awkward with the original small grey knobs, these new ones make it easy.
The heated bed cable needs re-routing under the Y azis instead of over otherwise it fouls these larger knobs, this involves unplugging the cable from the mainboard. This is relatively simple but involves removing a cover that exposes mains electricity so unplug the printer from the mains electricity. Also be wary of voiding any warranty. If you aren't happy about doing this you could just replace 3 knobs.
These knobs are skinny (3.4mm) otherwise they foul the Y axis rails, the centre boss that contains the nuts protudes a further 3mm. The diameter is 112mm which is as large as I could go without fouling the Y axis limit switch.
They need to be spaced off the bed frame with a thin steel washer,