# Bulkhead penetrator thread dimensions

**URL:** https://bristlemouth.discourse.group/t/bulkhead-penetrator-thread-dimensions/344
**Category:** Dev Kit Support
**Created:** [May 6, 2024, 6:29pm UTC](https://bristlemouth.discourse.group/t/bulkhead-penetrator-thread-dimensions/344 "2024-05-06T18:29:07Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![omolina](https://avatars.discourse-cdn.com/v4/letter/o/c68b51/32.png) [@omolina](https://bristlemouth.discourse.group/u/omolina)
#### Post date: [May 6, 2024, 6:29pm UTC](https://bristlemouth.discourse.group/t/bulkhead-penetrator-thread-dimensions/344/1 "2024-05-06T18:29:07Z")

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I am designing a larger endcap and need to incorporate your penetrators, but am unsure what the thread dimensions are and what clearance I need.

 ![image](https://canada1.discourse-cdn.com/flex029/uploads/bristlemouth/original/1X/02b9aa21cfd5cc2c8eabfad1ce15d51480478698.jpeg)

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### Author: ![zack\_j](https://yyz1.discourse-cdn.com/flex029/user_avatar/bristlemouth.discourse.group/zack_j/32/13_2.png) [@zack\_j](https://bristlemouth.discourse.group/u/zack_j)
#### Post date: [May 6, 2024, 9:35pm UTC](https://bristlemouth.discourse.group/t/bulkhead-penetrator-thread-dimensions/344/2 "2024-05-06T21:35:46Z")

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Hey there, thanks for posting this here. I’ve talked to some of the engineers at Sofar with the following advice:

- The through hole should be 16.5mm OD which should allow for easy clearance of the M16x1 threaded part.
- The o-ring is a face seal on the flat mating surface so no counterbore is recommended. If the through-hole is 16.5mm then the o-ring will have proper space for engagement on the flat surface of the endcap.

Does this make sense?

Thanks!  
Z

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### Author: ![zack\_j](https://yyz1.discourse-cdn.com/flex029/user_avatar/bristlemouth.discourse.group/zack_j/32/13_2.png) [@zack\_j](https://bristlemouth.discourse.group/u/zack_j)
#### Post date: [May 6, 2024, 9:45pm UTC](https://bristlemouth.discourse.group/t/bulkhead-penetrator-thread-dimensions/344/3 "2024-05-06T21:45:05Z")

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I’ve added a diagram for how the o-ring should sit on your endcap

 ![image](https://canada1.discourse-cdn.com/flex029/uploads/bristlemouth/original/1X/53f004ed31aa8b6e74f15d2772b0b1f9abeb0134.jpeg)

Notice it’s a clean through hole and not threaded with a clearance of 0.5mm diameter.