M5 rivet nuts are a popular choice for light sheet metal, small brackets, panels, enclosures, automotive interiors, equipment covers, and general fabrication. They create a reusable M5 threaded mounting point in material that may be too thin to tap directly.
The most important step is drilling the correct hole. A clean, correctly sized hole helps the rivet nut seat flat, collapse properly, and resist spinning.
Quick Answer
Many M5 rivet nuts use a hole around 7 mm. Some specific inserts may call for a slightly different hole size, such as 7.0 mm or 7.1 mm.
Always check the exact manufacturer’s specification before drilling the final part.
Common M5 Rivet Nut Hole Size
| Thread Size | Common Hole Size | Closest Inch Size | Notes |
|---|---|---|---|
| M5 x 0.8 | Around 7 mm | Around 9/32 in | Verify by insert style |
| M5 specialty styles | May vary slightly | Varies | Check the datasheet |
M5 rivet nuts are smaller than M6 and M8 inserts, so hole accuracy matters. A slightly oversized hole can make the rivet nut more likely to spin, especially in thin or soft material.
M5 Rivet Nut Drill Bit Size
For many M5 rivet nuts, a 7 mm drill bit is a common starting point. In imperial sizes, 9/32 inch is slightly larger than 7 mm.
If you are working with an imperial drill set, test the fit in scrap material before drilling the finished part. The rivet nut should insert cleanly and seat flat without excessive looseness.
Why M5 Rivet Nut Hole Sizes Vary
M5 rivet nut hole sizes vary because the outside body diameter changes from one insert style to another.
The required hole may depend on:
- Round body or hex body
- Smooth body or knurled body
- Flat head or countersunk head
- Standard flange or large flange
- Open-end or closed-end design
- Steel, stainless steel, or aluminum
- Grip range
Do not choose the drill size based only on the M5 thread. The internal thread is M5, but the outside body determines the hole size.
M5 Rivet Nut Grip Range
Grip range is the material thickness range that the rivet nut is designed to clamp. If the parent material is outside that range, the insert may not set correctly.
Before installing an M5 rivet nut, check:
- Material thickness
- Grip range
- Hole size
- Body style
- Flange style
- Installation tool setting
If the material is too thin, the rivet nut may not form a secure backside bulge. If the material is too thick, the rivet nut may not collapse enough to grip.
M5 Rivet Nut Installation Torque
Be careful with generic torque numbers. M5 rivet nut installation depends on the insert material, parent material, tool type, and grip range.
There are two separate concerns:
- Setting the rivet nut with the installation tool
- Tightening the M5 bolt after the rivet nut is installed
Do not over-tighten the bolt after installation. Smaller rivet nuts like M5 can be damaged if the bolt is tightened beyond what the insert and parent material can handle.
Common M5 Rivet Nut Installation Mistakes
Using a Hole That Is Too Large
If the hole is too large, the rivet nut may spin during installation or later when the screw is tightened.
Using a Hole That Is Too Small
If the hole is too small, the insert may scrape, deform, or fail to seat flat.
Ignoring Grip Range
The grip range must match the material thickness. This is just as important as the hole size.
Over-Tightening the Bolt
M5 hardware is smaller than M6 or M8, so it is easier to damage the threads, deform the insert, or crush thin material.
Using the Wrong Insert for Soft Material
Soft aluminum, plastic, fiberglass, and thin sheet metal may need a specific rivet nut style to avoid pull-out or spinning.
M5 vs M6 Rivet Nut
M5 is useful when space is limited or the load is relatively light. M6 is better when you need a stronger fastening point, larger bolt, or more common automotive/fabrication size.
Use M5 for smaller panels, covers, brackets, and light-duty attachments. Use M6 when the part needs more strength or when the hardware around the assembly is already M6.
Best Practice: Test First
Before drilling the final part, drill a test hole in scrap material with the same thickness. Install the M5 rivet nut and check that:
- The insert seats flat
- The backside collapses correctly
- The insert does not spin
- The bolt threads in smoothly
- The panel is not crushed or distorted
This quick test can prevent a ruined finished panel.
Related Guides
- M6 Rivet Nut Hole Size & Torque Guide
- M8 Rivet Nut Hole Size Guide
- Rivet Nut Hole Size Chart
- Rivet Nut Grip Range Explained
- Why Rivet Nuts Spin and How to Fix Them
FAQ
What size hole do I drill for an M5 rivet nut?
Many M5 rivet nuts use a hole around 7 mm, but the exact value depends on the insert style and manufacturer.
Is 9/32 inch close to 7 mm?
Yes. 9/32 inch is close to 7.14 mm, which is slightly larger than 7 mm. Test the fit before using it on the final part.
Why does my M5 rivet nut spin?
Common causes include an oversized hole, wrong grip range, under-setting, soft material, or using the wrong rivet nut body style.
Can I use M5 rivet nuts in aluminum?
Yes, but make sure the hole size, grip range, and insert material are suitable for the aluminum thickness.
Are all M5 rivet nuts the same outside diameter?
No. M5 refers to the internal thread. The outside body diameter can vary by insert style, which changes the required hole size.