Lately, I’ve been running all kinds of experiments at my workbench, and the need for a convenient, accessible tool rack has become increasingly obvious. So I went browsing on Makerworld and found a 3D print model that looked good and checked most of my boxes in terms of function – Desktop Tool Rack. It took me nearly 14 hours to print the whole thing.
When I started using it, however, I ran into an issue. The original designer had included a number of hex-shaped holes meant to hold interchangeable screwdriver bits—but they were all 8mm, which fit my large electric screwdriver just fine. However, I also have a smaller electric screwdriver that I use for disassembling electronics and circuit boards—and its bits are 4mm hex. These smaller bits couldn’t fit into the original slots at all, so storing them became a bit of a mess.
So I went back to the model and added a small upgrade of my own: a row of 4mm hex slots on the left side, specifically for these smaller bits. I also noticed some empty space in the center and decided to add a small rectangular recess—perfect for temporarily holding loose screws or tiny nuts during a project.
While editing the model, I realized the original designer had added chamfers all over the place- – even at the bottom of the screwdriver holes where you’d never see them. Honestly, those chamfers didn’t add much value—especially since you can’t even see them—but they definitely increased the print time. So I removed most of the internal chamfering in one go. The result? This new version printed over an hour faster, clocking in at just over 12 hours.
As I started transferring all my screwdriver bits to the new rack, a new problem quickly surfaced. I had only added 10 slots for 4mm hex bits and 12 for the 8mm ones. But I’ve accumulated a ridiculous number of these tiny bits over time—many of them oddly shaped or specialized, and somehow all feel too important to leave out. Trying to decide which ones to include felt like choosing a favorite child. So I opened up the model again, planning to add more slots. But then it hit me: reprinting the whole thing—for just a few extra holes—would mean another 12-hour print and nearly 600g of filament. That’s just… absurd.
While staring at the model in frustration, my eyes landed on the little square recess I had added for temporarily holding screws. And then – lightbulb moment – “Why not just design a standalone screwdriver bit holder module, and plug it into that existing square slot using a simple connector piece?”
That way, I wouldn’t have to reprint the entire organizer – I could just extend it. I did a quick estimate: this new module and connector would take just a little over 1 hour to print and under 100g of filament.
I didn’t waste any time – I jumped right back into sharp3D and designed two quick parts. The first was a simple rectangular connector block, super easy to print—took just about 15 minutes. It fits snugly into the square recess I had originally created for holding screws. Next, I designed a compact expansion module that can hold up to 36 of my 4mm hex bits—finally, enough space! The result looks pretty neat, if I say so myself!
I’m really happy with how this little module turned out, so I’ve gone ahead and published the project on Makerworld. It’s titled “4mm Screwdriver Bit Extension for Desktop Tool organizer” – straightforward and self-explanatory. I also uploaded a new print configuration for the original tool rack model. With that profile and this add-on, you’ll get storage for up to 46 4mm hex bits—plenty of room for all your precision driver needs. And if anyone needs to store other small tools, parts, heat shrink tubes, or even magnets – you can simply tweak this module’s design and print a new piece but no need to touch that 12+ hour print again.
Leave a Reply