FitCheck Support

Common questions

How do I find the hole size for my design?

FitCheck is a design-stage tool - you open it while you're in CAD or CAM, or before a print, to get the number you'll model or compensate for.

Open the Lookup tab and enter what you're fitting - a screw or bolt (M3, M5-0.8, #8-32), a bearing (608), or the hex nut for a size. Flip between Additive (FDM) and Subtractive (CNC) for how you're making the part, and it gives you the right hole or pocket for that process: clearance fits (close/normal/free), the tap drill on CNC or the self-tap pilot hole on FDM, the heat-set insert and hex nut pockets on FDM, and the machined bearing seat or printed bearing pocket - each with a cross-section. Whatever it shows is the number to design around.

What does calibration do and how do I calibrate a machine?

You can find everything about calibration here.

I paid for Pro but it's not unlocked

Open Settings and tap Restore Purchase. Pro is tied to your App Store / Google Play account, so it comes right back after a reinstall, or a fresh install on a new device - no second charge. If you still have trouble, reach out.

Is Pro a subscription?

No, it is a one-time purchase. No subscriptions, no recurring anything.

Does it work offline?

Completely. The whole catalog is loaded on your device and the app never needs a connection. Calibration and lookups all work without internet.

What do you do with my data?

Nothing, unless you allow us to. No account, no ads, no tracking. Your machines and settings stay on your device, and nothing leaves it unless you turn on optional, anonymous calibration sharing (Settings → Data sharing. It is off by default).

This sends us anonymous machine-tolerance measurements to help improve FitCheck. You can turn it off or delete what you've shared at any time. Details are in the Privacy Policy.

mm or inches?

Toggle units in the app to switch the whole catalog between millimeters and inches. There's also a Fractions tab for inch↔mm conversion and a 64ths ruler.

Where do the numbers come from?

Published standards - ISO 273 and ASME B18.2.8 for clearance holes, ISO 4762/ASME B18.3 for screw heads, DIN 934 for hex nuts, and the ISO 286 fits for bearing seats. Heat-set insert pockets have no standard, so those follow the published insert design guidelines instead. Other pocket clearances are our own engineering call, the app labels those a recommendation.

As much as I work to keep the data accurate, FitCheck is a reference - if you're cutting something important, verify against the standard and a test part first.

A dimension looks wrong

Please check a few things first:

• Is a calibrated machine active and shifting the number?
• Are you looking at the additive vs. subtractive spec, or comparing a different fit grade (close/normal/free)?

If you're sure a value is genuinely wrong, send over the fastener and the dimension and we'll take a look.

Found a bug or want a feature?

Email us at bakedbean3d@gmail.com or through the site - what you did, what you expected, what happened. Feature requests are welcome too!

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FitCheck is a product of Baked Bean LLC (d/b/a BakedBean3D), Illinois, USA.