# Altmill spindle mount holes

**URL:** <https://forum.sienci.com/t/altmill-spindle-mount-holes/16683>\
**Category:** 📄 General\
**Created:** [March 29, 2025, 2:03pm UTC](https://forum.sienci.com/t/altmill-spindle-mount-holes/16683 "2025-03-29T14:03:39Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Chucky\_ott](https://forum.sienci.com/user_avatar/forum.sienci.com/chucky_ott/32/8692_2.png) [@Chucky\_ott](https://forum.sienci.com/u/Chucky_ott)\
**Post date:** [March 29, 2025, 2:03pm UTC](https://forum.sienci.com/t/altmill-spindle-mount-holes/16683/1 "2025-03-29T14:03:39Z")

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The spindle mount on the Altmill has 4 holes on the front. They don’t show up as threaded in OnShape so I’m wondering what’s their purpose. If possible, I’d want to thread them in order to mount attachments.

 ![Screenshot 2025-03-29 095434](https://forum.sienci.com/uploads/default/original/2X/a/ab9cb8f46c04c7b4c0e2ad9b8eb298dae5d092ce.png)

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**Author:** ![fafesb](https://forum.sienci.com/letter_avatar_proxy/v4/letter/f/6bbea6/32.png) [@fafesb](https://forum.sienci.com/u/fafesb)\
**Post date:** [March 29, 2025, 2:09pm UTC](https://forum.sienci.com/t/altmill-spindle-mount-holes/16683/2 "2025-03-29T14:09:56Z")

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Those holes are primarily used to mount the Laser option!

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**Author:** ![Jens](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/d2c977/32.png) [@Jens](https://forum.sienci.com/u/Jens)\
**Post date:** [March 29, 2025, 2:22pm UTC](https://forum.sienci.com/t/altmill-spindle-mount-holes/16683/3 "2025-03-29T14:22:43Z")

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… and they are threaded on my Altmill … I believe 5 mm but not sure off hand.  
I use them to mount a secondary router for vertically held material.

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<div class="post-metadata">

**Author:** ![Chucky\_ott](https://forum.sienci.com/user_avatar/forum.sienci.com/chucky_ott/32/8692_2.png) [@Chucky\_ott](https://forum.sienci.com/u/Chucky_ott)\
**Post date:** [April 3, 2025, 12:52pm UTC](https://forum.sienci.com/t/altmill-spindle-mount-holes/16683/4 "2025-04-03T12:52:18Z")

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The holes on Onshape are 4.2mm, which is what would be used for M5x0.8 bolts. Can you tell me if the threads cover the entire length of the hole?

I’m ordering 18mm bolts to mount a 1/4" plate and want to make sure they’re not too long.

TIA

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<div class="post-metadata">

**Author:** ![Jens](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/d2c977/32.png) [@Jens](https://forum.sienci.com/u/Jens)\
**Post date:** [April 3, 2025, 2:58pm UTC](https://forum.sienci.com/t/altmill-spindle-mount-holes/16683/5 "2025-04-03T14:58:07Z")

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As far as I know, yes they are threaded all the way. IIRC, you do have to watch the length of the bolts so they don’t interfere with the spindle itself. You should be OK but if the screws stick out inside the spindle space you can easily add a washer to back the screw out a bit (well, I guess it depends on the head of your screw)