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These are improved knobs for the Customizable Adjustable Glass Bed Bracket for the FlashForge Creator Pro and similar printers. These knobs have a silicone gasket incorporated in them, which acts as a spring. As an alternative, you can print the springs using a flexible filament. The problem with the original knobs and many other brackets designs, is that the thermal expansion of the aluminum bed is much larger than that of the glass (especially borosilicate glass). This means if you tighten the knobs while the bed is cold and then heat it, it becomes larger than the glass. This causes the brackets to lose their grip, allowing the glass to shift around.

These spring-loaded knobs solve that problem by keeping on pushing against the brackets even if they move inwards a little due to the bed expanding. The gaskets are just thick enough to offer the required spring travel, without being too thick to make the brackets wobbly.

Some assembly and patience is required: you need to create your own silicone gaskets with a printable mold, or you can print them with a flexible filament. I provide molds for 3.5 mm and 4 mm tall gaskets. Which one is most suitable, will depend on how flexible the silicone compound is that you will be using. I suggest to simply print both molds, make two pairs of gaskets, and see which ones work best.
 

Method 1: make gaskets using silicone compound

Carefully read the instructions on the Customizable Gasket Mold Maker page. In a very short nutshell: print the molds in ABS, as it seems to adhere the least to silicone compound. Use RTV silicone if you can.
If you want even thicker gaskets, you can make your own with Customizer on that page. The inner diameter must be 10 mm and the outer diameter 14.1 mm. You could also try a gasket with a square profile to increase stiffness.

The nice thing is that you can already use the knobs without the gaskets while you're waiting for them to cure. You only need to remember to manually re-tighten the knobs after preheating the bed. Once you have the gaskets, unscrew the knobs, drop in the gaskets, and you're good to go.

Preparing the gaskets for use

Cut or pry off any excess silicone from the gaskets to make them nice and round. Make sure the gaskets are fully cured before assembling the knobs. RTV silicone gaskets should be ready to use, but for regular silicone, you should leave the gaskets in the open air for at least 24 more hours, probably longer for neutral cure compound. This allows them to cure further and release solvents still contained inside. Again, exposing them to humidity may speed up this process.
 

Method 2: print gaskets/springs with flexible filament

If you have a sufficiently flexible filament, you can print an effective spring instead. The Gasket-TPU-printable STL file can be printed as-is in TPU. Infill doesn't matter because the model is a hollow shape. The filament must be elastic and reasonably heat-resistant. I have tried this in NinjaFlex which seems to work well. Anything much harder than Shore 85A is likely to be too stiff to act as a spring.
 

How to use the knobs

Remove any remains of hairspray or glue stick from the bottom of the disks and brackets, to ensure these parts can easily slide against each other, otherwise tightening the knobs could be difficult. A wee bit of silicone grease/oil can help as well, you may need to re-apply this occasionally. Assemble and mount the knobs as shown in the photos.

You can adjust the knobs in two ways:

1. Preheat the bed to the highest temperature you'll use, and then tighten the knobs just beyond the point where the glass can no longer move.
2. Just tighten the knobs with the bed cold, to the point where there is only a tiny gap left between the disk and the knob.

Either method is fine, but the first one will minimize the amount of stress on the brackets and could prolong their lifespan. If you're not going to print for a while, it is advisable to loosen one of the knobs.

If you made the gaskets with regular silicone compound, they will be quite soft when freshly made, and become harder over the course of the next weeks. This means you may need to tighten the knobs more with freshly made gaskets.