What is the ideal hole size and thread engagement for tapping?

Designing the correct hole size when preparing for tapping is important. Holes that are too large may cause the tap to strip out or fail. If the hole is too small, it will cause the tap to bind, create excessive heat, wear, and could result in a broken tap trying to cut too much material. So we have a helpful chart for you to reference when choosing your hole and tap sizes.

Keep in mind, we will automatically resize holes to perfectly fit the tap size you select while configuring parts in our quote system. Circular holes up to 4.00″ should be selectable for tapping services in eligible material thicknesses.

The percentage of thread engagement in your design should be intentional. If not designed for correctly, too little or too much thread engagement could weaken your parts, cause distortion in the material, or damage your hardware. Though it’s dependent on the intended use and overall design, soft materials such as Aluminum, Brass, Copper, and plastics work best with more thread engagement (75% of thread). Hard materials, such as steel, benefit from less engagement (50-70% of thread).

Learn more about our tapping services in this video!

Start your first SendCutSend project today!

Upload your CAD design or use our parts builder and get instant pricing on your custom laser cut parts, all delivered to your door in a matter of days.