Bolt Hole Calculator — Clearance & Tap Hole Sizes

Standard clearance for M5 is 5.5mm. For 3D printing, add your printer tolerance (typically 0.15mm), so design at 5.65mm. Close fit uses 5.2mm + tolerance. These sizes allow the bolt to pass through without binding.

Yes, for M4 and larger in PLA and PETG. Print the hole at tap drill size + printer tolerance. Use a hand tap with cutting fluid. Go slowly to avoid cracking. For stronger threads, use heat-set brass inserts instead.

A counterbore is a flat-bottomed recess for socket head cap screws (hex bolts) to sit flush. A countersink is a conical recess for countersunk (flat head) screws. Counterbores are more common in 3D printed assemblies.

At minimum, 1.5x the bolt diameter of wall material around the hole. For M5, that means 7.5mm minimum from hole centre to edge. For load-bearing applications, use 2x bolt diameter for safety.