Thin knob for M3 nut

My Discoeasy has a bed level defect... but the bed is not adjustable in standard.
At the beginning, I could only print small parts... so I designed a small part !

This knob has been designed to be used with the self-locking
nut provided with the Dagoma Discoeasy 200 to fix the bed.
For each bed's support, you must use :
- a 25 mm countersunk head screw,
- a small spring (I don't know the reference because I re-used old springs but something like 5mm x 10mm)
- 2 standards M3 nuts

Put the self-locking nut in the knob.
Fix the screw on the bed with a standard nut.
Screw the knob, the self-locking nut side looking the bed
Re-do it for each hole on the bed.
Then put bed on its support
Put the spring on the screw on the back of the support
Screw the other nut to maintain the spring (this is the more complex part!)
Re-do it for each support

Now, by screwing or unscrewing you may adjust the bed level. It can be screwed with a wrench or by hand. Make sure that the knob is