If all you want is a bolt that can be thumb tightened, here is a way to get there. The M4 bolt I used has a hex head with measurement of about 7mm across (flat-to-flat) and a depth of 3mm. My thumb screw part sits around the bolt head which can be secured with a suitable glue, eg. CA glue, Epoxy resin.

My print is made in 1.75mm eSUN PLA+ filament, with 0.2mm layer height and 15% infill on a Bambu X1 Carbon printer. Print supports are not required.

I hope that you can find this print useful, too.

Remember to leave me some feedback or even a tip to keep me enthused to make more of these drawings.