Rivet & Chicago Screw Length Calculator
Match cap-rivet post length and Chicago screw barrel to your leather thickness.
Quick answer
Choose a rivet post about 2–3 mm longer than the total leather thickness you are joining, so the cap has material to fold over. For example, two layers of 5 oz leather make a ~4 mm stack and take an 8 mm post or a 6 mm Chicago screw. Enter your leather weight and number of layers for the exact size.
Use a 8 mm rivet post
Fastener through your stack
How to size a rivet
A cap rivet locks when its post is pushed up into the hollow cap and mushrooms over. For that to happen the post has to be a little longer than the leather — about 2–3 mm proud before setting. Too long and it folds sideways instead of upward; too short and the cap never grips. Chicago screws are simpler: pick a barrel that sits just below flush so the two heads clamp the leather without a gap.
Rivets, screws & setters
For a 4 mm stack.
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Double-Cap Rivets Assortment
- Size
- 6/8/9/10/12 mm posts
- Level
- Beginner
Two capped faces for a finished look both sides. Post length must match your leather stack — see the rivet calculator.
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Rapid / Single-Cap Rivets
- Size
- assorted
- Level
- Beginner
One capped face, one flat — quick and cheap for hidden joins. Set on a hard surface with the matching tool.
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Rivet Setter + Anvil
- Size
- setter + concave anvil
- Level
- Beginner
The concave anvil and domed setter shape the cap without flattening it. Match the setter size to the rivet cap.
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Chicago Screws Assortment
- Size
- 4-12 mm barrels
- Level
- Beginner
Screw-together posts for removable, no-tools joins — ideal for straps you may adjust. Barrel length ≈ your leather stack.
Rivet & Chicago screw size chart
| Leather stack | Cap rivet post | Chicago screw | Example use |
|---|---|---|---|
| 0–1.6 mm | 4 mm (Extra-short) | 4 mm | One thin layer (2-4 oz): light closures, keychains |
| 1.6–3.2 mm | 6 mm (Short) | 5 mm | Two thin layers or one 6-8 oz: wallet closures, light straps |
| 3.2–4.8 mm | 8 mm (Medium) | 6 mm | Wallet + strap or one 8-10 oz: bag straps, belt keepers |
| 4.8–6.4 mm | 9 mm (Long) | 8 mm | Belt + keeper, doubled straps, dog collars |
| 6.4–8 mm | 10 mm (Extra-long) | 10 mm | Thick doubled belt leather, heavy straps |
| 8–12 mm | 12 mm (XL) | 12 mm | Very thick stacks, multiple straps, saddlery |
Frequently asked questions
What size rivet do I need for leather?
Pick a post about 2–3 mm longer than your total leather thickness. Two layers of 5 oz leather is ~4 mm, so an 8 mm post is right; the extra length is what folds into the cap.
What length Chicago screw for two layers of leather?
Match the barrel to your stack thickness. Two 5 oz layers (~4 mm) take a 6 mm barrel; the post should sit just below flush so the heads clamp tight.
Why does my rivet bend over instead of setting?
The post is too long for the stack, so it buckles sideways instead of mushrooming into the cap. Drop to a shorter post or add a layer.
Rivets or Chicago screws — which is better?
Rivets are permanent and stronger; Chicago screws are removable and let you swap parts. Use rivets for load-bearing joins, screws where you may adjust later.