Captive Nuts
By Lex Dodson
The sun rises, the sky is blue, dogs bark, and threading sheet metal sucks. Fortunately, there are lots of little shortcuts, but most of them require very soft materials, welding, or special installation tools. One type, the captive nut (also known as an insert nut) requires none of the above. An arbor press or a careful hammer blow will do just fine, and they can work with very thin materials.
While captive nuts are not exactly new, they’re surprisingly rare, but McMaster-Carr is an excellent source for these parts. They’re available in most small ANSI inch and ANSI metric thread pitches, and at around $5 for a pack of ten, it’s a small price to pay for not needing to worry about losing track of tiny parts.
Captive Nuts [McMaster-Carr]
September 10th, 2009 at 4:43 pm
There’s also Rivnuts.
September 10th, 2009 at 9:19 pm
I don’t get it… how do they work?
September 10th, 2009 at 11:25 pm
bang them in the opposite side of where you want to screw in a bolt. The teeth grip the hole so it doesn’t fall out and the bolt will pull it towards itself, also keeping it from falling out.
September 11th, 2009 at 11:51 am
We’ve have used nutserts - like Rivnuts - for years to add a threaded insert to sheetmetal. As pointed out you do need a tool to crimp them into place:
http://www.imperialsupplies.com/grp270.shtml
I think that USM or others may sell boxes of inserts that come packaged with a mandrel that can be used with your pop-riveter. Admittedly, pop riveters are not as ubiquitous as hammers.
September 14th, 2009 at 10:46 am
[...] recent post on captive nuts reminded me of some other nuts I’ve been using a lot lately while doing some [...]