What is the proper name for this?

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Well-Known Member
Jan 21, 2009
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I have a couple of these--they are basically a rubber mount. It is used when you only have access to the front side of a thin plate to mount something to. The rubber expands when the screw is tightened to lock it down.

Does this have a specific name, and would you know where I can more of these? The ones I have are small, about 3/16" hole diameter.


AKA a well nut. Some folks use them for their rail buttons.
Yep, it is a well nut at McMaster. Thanks!

Though, rubber for a rail button? Doesn't sound efficient to me. :confused:

No...it's not used FOR the rail button, it's used to MOUNT the rail button. I use these on all my rockets. Drill the hole, stick in the well nut, then screw the rail button into it. Makes for easy removal of rail buttons in case of damage or whatever. The well nut will expand when the screw is inserted and "locks it in"...easy and secure!

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