# Tool Holders & Collets

The Snapmaker Artisan uses **ER11 collets** as the standard tool-holding system.\
ER11 is compact, widely available, and well suited for the small tool diameters commonly used on desktop CNC machines.

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### **About the ER11-A nut**

The **“A” refers only to the nut design**, not to the collet itself.\
Collets are simply **ER11 collets** and are interchangeable regardless of nut style, as long as the system is standard ER11.

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### **Collet sizes and tool diameters (ER11)**

ER11 collets are sized by their **maximum clamping diameter** and typically have a **0.5 mm collapse range**.\
This means an ER11 collet marked **4.0 mm** is designed to clamp tools from **4.0 mm down to 3.5 mm**, but **not larger than 4.0 mm**.

In practice, ER11 collets are commonly available in **0.5 mm size steps** (e.g. 3.0, 3.5, 4.0, 4.5, …).

**Practical sizing guidance:**

* **3.175 mm (1/8") tool** → **ER11 1/8" collet (preferred) or ER11 3.5 mm collet**
* **3.5 mm tool** → **ER11 3.5 mm collet**
* **3.6 mm tool** → **ER11 4.0 mm collet**
* **4.0 mm tool** → **ER11 4.0 mm collet**

Do **not** clamp a tool that is **larger than the collet’s marked size**.\
Avoid clamping tools at the extreme end of the collapse range when possible.

Choosing the closest correctly sized collet improves grip, reduces runout, and keeps cutting behavior predictable.

***

### **Search terms to buy**

15pcs piece ER11 collet set 1.0 - 7.0 mm & 1/4 1/8

{% hint style="info" %}
**15-pcs ER11 collet set (1.0–7.0 mm + 1/8″ + 1/4″)** — a common starter set that covers metric tools and the two most common imperial shank sizes, allowing you to choose a closely matching collet in most cases.
{% endhint %}


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