posts/3ring.md

diff --git a/posts/3ring.md b/posts/3ring.md
new file mode 100644 (file)
index 0000000..2f91244
--- /dev/null
+++ b/posts/3ring.md
@@ -0,0 +1,35 @@
+---
+author: admin
+categories:
+- Non-technical
+date: 2025-04-12
+tags:
+- standards
+- organization
+title: '3-ring binder spacing'
+---
+
+I recently tried to buy a 3-ring binder, and I was annoyed didn't list spacings on paper OR binders. This is my attempt to write a reference for future searchers.
+
+The spacing between rings seems to be standard. The ring size itself isn't standard. Holes vary from 6-8mm.
+
+Here are the spacings I found. If you encounter a 3-ring binder not listed, or pre-punched paper that doesn't match the below, please email me with the measurements and brand name.
+
+Paper sizes:
+- **US Letter**: 215.9x279.4 mm / 8.5x11 inch
+- **A4**: 210 x 297 mm / 8-1/4 x 11-3/4 in
+- **A5**: 148 x 210 mm / 5-7/8 x 8-1/4 in
+- **A6**: 105 x 148 mm / 4-1/8 x 5-7/8 in
+- **Filofax** (brand name): 95x170 mm / 3.75x6.7 inch
+- **SMD parts sheets** (unclear if standardized): 117x175 mm; A6 6-ring spacing
+
+**US Letter, 3-ring**: Aka "standard" 3-ring binders in the USA.
+    - 108mm hole spacing
+**A5, 3-ring**: In Staples, I found these sold as "mini" binders.
+    - 70mm hole spacting
+**A5, 6-ring**:
+    - 19mm hole pitch, 70mm central gap
+**A6, 6-ring**:
+    - 19mm hole pitch, 40mm central gap
+**Filofax, 6-ring**: 
+    - 19mm hole pitch, 50.8mm central gap