I call these parts "corner clamps"...

Now, after optimization and upgrading, the problem of the thumb screw penetrating the bottom of the heatbed has been completely solved. I installed small spacers between the screw and the heatbed as a transition connection. These spacers are equipped with a dedicated support structure in the design, which is firmly installed and looks beautiful.

This clamping fixture is a customized solution I designed for Home Depot's glass mirrors. I selected glass mirrors with a thickness of 3.8 mm, each measuring 12 inches × 12 inches × 0.1 inches. I fixed three mirrors to the four corners of the un-wired heatbed. The corner clamps have been upgraded to perfectly fit the mirror dimensions and precisely match the screw hole diameter, ensuring secure installation. Additionally, the clamps have further optimized the pressing structure, which effectively secures the glass mirrors to the heatbed and prevents warping. The actual usage results are excellent

When using this clamp, it is recommended that you go to Home Depot to purchase a 12-inch × 12-inch × 0.1-inch glass mirror. By the way, go to the hardware section to select the half-inch-long, 10-24-spec thumb screws they sell, and it is recommended to prepare two extra packs. Initially, when I designed the corner clamp, I used 10-24 positioning screws with a length of 5/16 inches; however, when the heatbed heats up, the adjustment of these screws often requires the use of tools, which is both

Special reminder: Some users have reported that the thickness of the glass mirrors sold at Home Depot in other regions may not exactly match the 3.8 mm I used. However, my corner clamps were designed based on this specific thickness. If the mirror you have is not 3.8 mm thick but you still want this design to fit perfectly, I'd be happy to customize an adjustment plan for you to ensure the clamps perform optimally.