# NEMA 34 shaft size

**URL:** <https://forum.avidcnc.com/t/nema-34-shaft-size/3633>\
**Category:** General Chat\
**Created:** [August 26, 2024, 10:39pm UTC](https://forum.avidcnc.com/t/nema-34-shaft-size/3633 "2024-08-26T22:39:24Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![CNCWilson](https://avatars.discourse-cdn.com/v4/letter/c/87869e/32.png) [@CNCWilson](https://forum.avidcnc.com/u/CNCWilson)\
**Post date:** [August 26, 2024, 10:39pm UTC](https://forum.avidcnc.com/t/nema-34-shaft-size/3633/1 "2024-08-26T22:39:24Z")

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I have NEMA 34 motors with STANDARD 14mm shafts. The rack and pinion drive gear is for a 12.67mm (1/2") shaft. What am I missing here?

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**Author:** ![grossmsj](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/grossmsj/32/4903_2.png) [@grossmsj](https://forum.avidcnc.com/u/grossmsj)\
**Post date:** [August 26, 2024, 11:04pm UTC](https://forum.avidcnc.com/t/nema-34-shaft-size/3633/2 "2024-08-26T23:04:45Z")

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Bummer.  
The shaft diameter on my Teknic Clearpath Servos is 12.7mm. Seems there is more than one standard. But I am sympathetic because the Avid hole sizes for mounting the motors is M6 and the Clearpath Servos are M5. This is a particular problem on the Z-axis. I did NOT want to drill out my motors, so I resorted to using M6 to M5 Toyota Antenna Thread adapters. Sheesh!  
[34xx CPM Dimensional Drawing.pdf](https://forum.avidcnc.com/uploads/short-url/uZi29MmCyr0lbosTEQtnG15COFf.pdf) (636.7 KB)

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**Author:** ![djdelorie](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/djdelorie/32/515_2.png) [@djdelorie](https://forum.avidcnc.com/u/djdelorie)\
**Post date:** [August 27, 2024, 12:18am UTC](https://forum.avidcnc.com/t/nema-34-shaft-size/3633/3 "2024-08-27T00:18:42Z")

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> [@CNCWilson](#):
>
> I have NEMA 34 motors with STANDARD 14mm shafts.

The wonderful thing about standards is that there are so many to choose from.

My NEMA 34 servos have standard 3/8" D-shafts on them. They’re SO standard I have to make my own gears!

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<div class="post-metadata">

**Author:** ![CNCWilson](https://avatars.discourse-cdn.com/v4/letter/c/87869e/32.png) [@CNCWilson](https://forum.avidcnc.com/u/CNCWilson)\
**Post date:** [August 27, 2024, 2:17pm UTC](https://forum.avidcnc.com/t/nema-34-shaft-size/3633/4 "2024-08-27T14:17:19Z")

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I found some 14mm gears with 5mm spacing from another vender.  
Anyone needs the 1/2" gears, I will send them to you.