<p>T stands for <a href="https://en.wikipedia.org/wiki/G-code#Letter_addresses" rel="nofollow noreferrer">"Tool"</a> and has its origin in the origins of <a href="https://en.wikipedia.org/wiki/G-code#Letter_addresses" rel="nofollow noreferrer"><code>.gcode</code></a> being for other automated machine controls. Depending on the machine, everything could be a tool for <code>.gcode</code>, like an actuator or pump or a spindle motor or a drill.</p>

<p>In 3D printers, the T-controlled tool is usually the <strong>extruder motor</strong>. Convention has it that the indexing always starts at 0, so T0 and T1 are your first and second Extruder respectively. It is the way to choose which tool is used. </p>

<p>As a side note: E is not originally intended for extruders but for the feed rate of lathes.</p>

CC BY-SA 4.0
2019-03-12T20:41:46.073Z
2019-03-13T23:58:00.047Z
2019-03-13T23:58:00.047Z
Trish
<p>I'm not sure what it's doing in your case, but the "T" code is there to select the extruder number. T0 would be the first and T1 would be the second extruder in a multi-extruder setup. I found the information at the end of <a href="http://www.makeit-3d.com/wp-content/uploads/RepRapGcodeCheatSheet.pdf" rel="nofollow noreferrer">this cheat sheet</a>. </p>

CC BY-SA 4.0
2019-03-12T20:27:48.157Z
2019-03-12T20:27:48.157Z
Pᴀᴜʟsᴛᴇʀ2
<p>I'm using IdeaMaker for slicing my print objects. IdeaMaker start strings have a >T0&lt; standing alone on one line and then >T1&lt; on the next line. What does this accomplish?</p>

CC BY-SA 4.0
2019-03-14T07:18:41.967Z
Could you post a snippet of the "`start strings`" (is that start G-code script?) so everyone knows what you mean? E.g. is it commented out or not, please let us see.
0scar
<marlin><g-code><ideamaker>
What does a stand alone "T" index value do?
Mouser
# What does a stand alone "T" index value do?

(Asked by: username_0 on 2019-03-12)

I'm using IdeaMaker for slicing my print objects. IdeaMaker start strings have a >T0< standing alone on one line and then >T1< on the next line. What does this accomplish?

**Tags:** marlin, g-code, ideamaker
> **Comments:**
> **username_1**: Could you post a snippet of the "`start strings`" (is that start G-code script?) so everyone knows what you mean? E.g. is it commented out or not, please let us see.  

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## 2 answers

### Answer by username_2 on 2019-03-12. Score: 6

T stands for ["Tool"](https://en.wikipedia.org/wiki/G-code#Letter_addresses) and has its origin in the origins of [`.gcode`](https://en.wikipedia.org/wiki/G-code#Letter_addresses) being for other automated machine controls. Depending on the machine, everything could be a tool for `.gcode`, like an actuator or pump or a spindle motor or a drill.

In 3D printers, the T-controlled tool is usually the **extruder motor**. Convention has it that the indexing always starts at 0, so T0 and T1 are your first and second Extruder respectively. It is the way to choose which tool is used.

As a side note: E is not originally intended for extruders but for the feed rate of lathes.


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### Answer by username_3 on 2019-03-12. Score: 2

I'm not sure what it's doing in your case, but the "T" code is there to select the extruder number. T0 would be the first and T1 would be the second extruder in a multi-extruder setup. I found the information at the end of [this cheat sheet](http://www.makeit-3d.com/wp-content/uploads/RepRapGcodeCheatSheet.pdf).


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