Spring-loaded Knobs for Adjustable Glass Bed Bracket

thingiverse

These are upgraded knobs for the Customizable Adjustable Glass Bed Bracket designed for the FlashForge Creator Pro and similar printers. These knobs feature an integrated silicone gasket that acts as a spring, providing a reliable grip on the glass even when the bed expands due to heat. As an alternative, you can print the springs using flexible filament. The problem with original knobs and many other bracket designs is that thermal expansion of aluminum beds exceeds that of glass (especially borosilicate glass). This leads to loose brackets and shifting glass if tightened while cold. These spring-loaded knobs resolve this issue by continuously applying pressure on the brackets, even when they move inward due to bed expansion. The gaskets are precisely designed to offer the required spring travel without making the brackets wobbly. Some assembly and patience are required: you need to create your own silicone gaskets with a printable mold or print them using flexible filament. I provide molds for 3.5 mm and 4 mm tall gaskets, which one is most suitable will depend on the flexibility of the silicone compound used. **Method 1: Making Gaskets Using Silicone Compound** Carefully read the instructions on the Customizable Gasket Mold Maker page. In brief: print the molds in ABS as it adheres least to silicone compound. Use RTV silicone if possible. You can also make thicker gaskets using Customizer on that page, with an inner diameter of 10 mm and outer diameter of 14.1 mm. A square-profiled gasket may increase stiffness. The nice thing is that you can already use the knobs without gaskets while waiting for them to cure. Just remember to manually re-tighten the knobs after preheating the bed. Once cured, unscrew the knobs, drop in the gaskets, and you're good to go. **Preparing Gaskets for Use** Cut off any excess silicone from the gaskets to make them round. Ensure the gaskets are fully cured before assembling the knobs. RTV silicone gaskets are ready to use, but regular silicone ones should be left in open air for at least 24 hours or longer for neutral cure compound. **Method 2: Printing Gaskets/Springs with Flexible Filament** If you have a 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 since the model is hollow. The filament must be elastic and heat-resistant. I've tried NinjaFlex which works well. **Using the Knobs** Remove any remains of hairspray or glue stick from the bottom of the disks and brackets to ensure easy sliding. A wee bit of silicone grease/oil can help, you may need to reapply 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, then tighten the knobs just beyond where the glass can no longer move. 2. Tighten the knobs with the bed cold to the point where there is only a tiny gap left between the disk and knob. Either method is fine, but the first one will minimize stress on the brackets and prolong their lifespan. If not printing for a while, it's advisable to loosen one of the knobs.