This ONE tool will save you HOURS!

Every maker has that moment. You're deep in a design, feeling the flow... and then you need to know the counterbore depth for an M8 socket head bolt. Again. So you dig through a pile of loose hardware on your desk, grab the calipers, measure something you've measured a dozen times before, guess at the clearance, print a test, and hope. That cycle? It's the real enemy of creative momentum.

Alexandre Chappel built something deceptively simple that solves this problem. A set of free, downloadable 3D printed reference boards that give you exact dimensions for press fits, slip fits, counterbores, and countersinks across metric bolt sizes M3 through M10.

No more guessing. No more reprinting because you were 0.2mm off.

Print the boards once. Keep them at your desk. Reference them forever.

What the Boards Actually Do

Each board is dedicated to a single bolt size and covers the hardware scenarios you hit constantly:

- Counterbore dimensions for socket head bolts... width, depth, and hole diameter for a clean slip fit - Nut recesses for both hex and square nuts, press fit and slip fit - Countersink angles for flush-mounted bolts - Washer combinations for load distribution on plastic parts - Press fit pockets where the nut stays put when you need it to

Every dimension is printed right on the board in contrasting text. You don't need to remember anything. You don't need to open a spreadsheet. The answer is sitting on your desk, proven in plastic.

The boards come organized in a printed tray. That heap of random bolts and sticky notes? Replaced by something that actually respects your time.

The Clearance Problem Nobody Talks About Enough

Here's what trips people up in CAD design: a 6mm hole doesn't print at 6mm. FDM printing introduces dimensional variance based on material, temperature, and... this is the sneaky one... print orientation.

A hole printed flat on the bed behaves differently than the same hole printed vertically. Print it at an angle? Different again. The overhangs on vertical holes cause the tops to collapse slightly, changing your fit entirely.

Chappel addressed this by creating separate hole-clearance test boards printed in three orientations: flat, vertical, and angled. Each board has holes from 2mm to 10.9mm in 0.1mm increments. You take your hardware, try it in the holes, and instantly know what dimension to model.

No math. No guessing. Just physical truth.

That 6mm shoulder bolt you need a slip fit for? Press it into the 6.0mm hole... too tight. 6.1... still snug. 6.2... slides in and out with zero wiggle. Done. Model it at 6.2.

One Extruder? No Problem

The text on these boards is multi-color, which looks clean on a Bambu Lab multi-color printer. But Chappel made sure budget setups aren't left behind.

The technique is beautifully low-tech: all the text lives on the very top layer. Print everything in one color, add a pause in your slicer right before that final layer, swap to a contrasting filament, resume. BAM, crisp two-tone reference text from a single-extruder machine.

This is the kind of practical maker knowledge that doesn't get enough spotlight. Small trick. Huge accessibility win.

The Thread ID Board

Bonus tool. A board with male and female threads for each metric size. Got a mystery bolt? Thread it into the board until one fits. Got a random nut? Drop it onto the posts. Five seconds to identify hardware you'd otherwise be measuring and cross-referencing against charts.

Why This Actually Matters

Let's zoom out for a second.

The friction in hobby 3D printing isn't the printer. It's not the software. Both have gotten remarkably accessible... a solid printer costs less than a third of the new iPhone, and professional CAD software like Onshape and Fusion 360 are free for hobbyists.

The friction is the repetitive grunt work between your idea and your finished part. Measuring the same hardware. Guessing at tolerances. Reprinting test pieces. Losing the bolt you were just holding.

These reference boards eliminate an entire category of wasted time. They turn hardware integration from a trial-and-error slog into a lookup operation.

And here's the part I love most... the whole thing is built on a simple insight: standardized hardware plus known clearance values equals precision you can repeat. That's it. No fancy technology. No subscription. Just someone who got tired of solving the same problem twice and decided to build the tool that should have existed all along.

That's the maker spirit at its core. You see a friction point, you build the fix, and then... you give it away.

The CAD Trick Worth Stealing

One more gem buried in this project: Chappel models tiny bridge layers inside hexagonal nut pockets so they print clean without supports. The bridges span the gap just enough to let the printer cross the void, then you punch through them when you insert the hardware.

This technique works everywhere... any recessed feature, any pocket where you'd normally need supports that leave ugly surfaces. File it away. You'll use it.

Every tool here is free to download at alch.shop. Print the sizes you use most. Stick them next to your calipers. Next time you're mid-design and need a counterbore depth for an M6 socket head... you'll just look down. No measuring. No reprinting. No breaking your creative flow for a problem you already solved last month. Build the reference once. Create faster forever. ✨

--- Source: https://www.youtube.com/watch?v=84RoiS-HiiM