I recently got into Gridfinity and started to see everything in multiples of 7. Turns out, the top of the A1 fits exactly a 9x1 baseplate. Almost as if Bambu Labs designed it that way.

Installation Details:

You'll need to screw the baseplate into the arm. For that you'll need to exchange the installed M3x8 screws with M3x12 screws. Note: the screws aren't ISO metric threads, but something else. If somebody knows what they're called, please let me know!

You can find the perfect screws in the AMS lite Top Mount Screws Kit. If you've bought them, like me, and didn't like the AMS on top and have these screws lying around, then this is the perfect usecase for these.

Other Infos:

I've also designed a cover that goes below the baseplate, which you can see in the pictures. This is optional and purely for aesthetics.

The baseplate supports the usual 6x2mm magnets. I haven't installed mine yet, since I wanted to print the baseplate with a silver filament, that hopefully matches the aluminum color of the printer.

The baseplate is too large for the printbed and is therefore cut up into two parts, joined by a dovetail.

Do let me know what you think about this and post pictures of the awesome gridfinity bins you put on top! I still need some inspiration for that. Have fun :)