Fastener & Heat-Set Insert Hole Size Reference
Verified hole diameter and pocket depth dimensions for M2, M2.5, M3, M4, M5, M6 heat-set inserts, tap holes, and clearance screws.
| Fastener | Screw OD | Close Clearance | Free Clearance | Heat-Set Hole | Heat-Set Depth | Tap Drill | Self-Tap |
|---|---|---|---|---|---|---|---|
| M2 | 2.00 mm | 2.20 mm | 2.40 mm | 3.20 mm | 4.0 mm | 1.60 mm | 1.80 mm |
| M2.5 | 2.50 mm | 2.70 mm | 2.90 mm | 3.60 mm | 5.0 mm | 2.05 mm | 2.20 mm |
| M3 | 3.00 mm | 3.20 mm | 3.40 mm | 4.00 mm | 5.7 mm | 2.50 mm | 2.70 mm |
| M4 | 4.00 mm | 4.30 mm | 4.50 mm | 5.60 mm | 8.1 mm | 3.30 mm | 3.60 mm |
| M5 | 5.00 mm | 5.30 mm | 5.50 mm | 6.80 mm | 9.5 mm | 4.20 mm | 4.50 mm |
| M6 | 6.00 mm | 6.40 mm | 6.60 mm | 8.00 mm | 12.0 mm | 5.00 mm | 5.40 mm |
| 1/4-20 (Tripod) | 6.35 mm | 6.60 mm | 7.00 mm | 8.70 mm | 12.7 mm | 5.10 mm | 5.60 mm |
Measurement & Operating Instructions
1. Filter Table
Type M2, M3, M4, M5, M6, or 1/4-20 to find your target screw size instantly.
2. Toggle Tolerance
Check the "Add Typical FDM Hole Shrinkage" box to add a safe +0.20mm allowance for FDM printing.
Standard Metric & Imperial Fastener Hole Reference
Verified drill, tap, heat-set insert, and clearance hole dimensions based on ISO 273 and Ruthex/Voron specifications.
Hole Dimension = Nominal Fastener Major Diameter + Clearance OffsetFor an M3 screw: Close clearance is 3.20mm, Free clearance is 3.40mm, and a standard M3x5.7 brass heat-set insert requires a 4.00mm hole with 5.7mm depth.
Frequently Asked Questions
What hole size do I need for an M3 heat-set insert?
What is the correct temperature for installing brass heat-set inserts?
What hole size should I design for direct self-tapping M3 screws in plastic?
What clearance hole diameter is needed for an M3 bolt pass-through?
Why do brass heat-set inserts pull out under tension?
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