Comfortable Knob with Embedded Bolt

I worked a long time to figure out how to permanently embed a bolt in a 3D printed knob without gluing. Here is my idea. I have printed a few of these and they work very well. This one is designed to accept a 1/4 inch bolt with a length of 1in. Yes, I use mostly metric, but I had quite a few of these bolts laying around, so I figured that I would use them up.

I have not redesigned this to work with any other bolts yet.

Printing is very specific. Orientation is with the manually added support down and the knob UP. Use supports from build plate only, but use a support blocker for the center part that the bolt is embedded in (hex head and shank). Nothing should print within the interior cavity (where the bolt goes). Have the printer pause right before it extrudes over the hex cavity in the knob. If you set up your supports and pause correctly, the bolt should drop right in and the printer should be able to continue printing the rest of the knob without trouble.

I am not sure ho