> For the complete documentation index, see [llms.txt](https://hmb-robotics.gitbook.io/documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hmb-robotics.gitbook.io/documentation/bumper-mounts/bumper-mounts-overview/bumper-plunger.md).

# Bumper Plunger

<div><figure><img src="/files/f83mtNiayR1KfBKpVZHl" alt="" width="143"><figcaption></figcaption></figure> <figure><img src="/files/mCtEVH2kPFU934aYryGy" alt="" width="130"><figcaption></figcaption></figure> <figure><img src="/files/5GBBiZVDLLwWpwH4SoxE" alt="" width="184"><figcaption></figcaption></figure> <figure><img src="/files/4O85bLDwA2e6XPsnIjX1" alt="" width="186"><figcaption></figcaption></figure></div>

Slides onto the round headed 1/4-20, 3.5" long through bolts (<https://www.mcmaster.com/90185A414/>) with the plunger side facing into the hole. After the plunger is on the bolt, slide a 1.125", 0.36" OD, 0.308" ID Spring (<https://www.mcmaster.com/9434K71/>) onto the bolt, and finally a a #10-32 nyloc nut (<https://www.mcmaster.com/90631A411/>) is screwed on the bolt to keep the full assembly together (Onshape has an updated model of this).

**STEP:**

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**STL:**&#x20;

{% file src="/files/NIwzTjxr2oVWfitgwQvC" %}