Using Riv-Nuts

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katou
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Joined: Jul 22, 2009 7:52 am

Using Riv-Nuts

Post by katou » Apr 02, 2011 11:58 am

How to Install and Use Rivnuts FAQ

I guess that these are called Rivnuts / Riv-nuts / Riv nuts / Blind Nuts / Nut-sert

or in generic terms, a blind-hole rivet containing an internally threaded hole for use on thin materials.

On your bike, the water bottle holder attaches to riv-nuts. Look closely and you'll see the threads inside the hole where the bolts go in.

Anyway, I needed to use them to mount my battery box to my thin aluminum frame. I considered putting bolts straight through, but I was pretty sure it would crush the tubing. It's a good thing I didn't try that, after seeing how thin the metal was, I'm definitely sure that it would have crushed.

Rivnuts come in aluminum and steel. I could only get the aluminum kind at my local specialty fastener store.

The process of setting a Rivnut is very simple, but because this sort of thing isn't something we do every day, it is very confusing to explain in words, but I'll try.

1. drill hole to fit rivnut (ideally the hole should be small enough that you have to tap very lightly to get it to go in)
2. put rivnut on tightening device
3. tighten rivnut device
4. done!

As you can see just the words are about as useful as having the perfect size wrench for a completely stripped nut. Before I show you my pix, here are some tools you can use:

Pro Rivnut setting Tool
http://www.fjr1300.info/howto/rivnut.html

Homemade rivnut setting Tool
http://www.fjr1300.info/howto/rivnut-tool.html

Cute cheap commercial setting tool
http://mdmetric.com/prod/rivetnuttool/rivetnuttool.htm

The Tool

My version is made from what I had around, but it works pretty well. The Allen head bolt holds the rivnut still, and the nut moving down the bolt pulls the rivnut into compression. The two washers are necessary, as well as a bit of oil between them. If you only use one washer, the nut rotation turns the washer, and the washer rotates the rivnut in the hole.

This is bad because if the rivnut rotates, it may accidentally enlarge the hole you drilled. Large hole means the rivnut falls out and never becomes secure. This may be less of a problem on steel, but it sure is a problem on thin aluminum like on my bike frame. I had to do two over before I realized why it was happening. The oil helped a lot too.
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Step 1 - 1/8" or 1.5mm hole drilled into thin material as pilot hole
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Attachments
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Step 2 -hole drilled out to full (very tight) size of Rivnut
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Step 3 - exploded view of my homemade rivnut tool
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Step 4 - tool partially assembled
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Step 5 - tool completely assembled with rivnut threaded on
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Step 6 - rivnut in hole, but not started compression
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step 7 - tool threaded into rivnut, ready to start compression
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Step 8 - tool in working position
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Rivnut with beginnings of compression showing
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Rivnut ~ 1/2 compressed
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Rivnut finished side view
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Rivnut finished front view
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Tool in operation compressing rivnut, wood is for contrast
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Rivnut finished. Note: new larger rivnut in lower hole, upper hole is original smaller rivnut for water bottle. Wood is for contrast
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Reference, Rivnut before and after compression
IMG_3789 - Copy.JPG (46.97 KiB) Viewed 6169 times

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spinningmagnets
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Re: Using Riv-Nuts

Post by spinningmagnets » Apr 09, 2011 12:55 pm

I have had good luck with nutserts/rivnuts. In the application I use, I just drill a hole in wood or aluminum plate for custom brackets, then epoxy a nutsert in from the inside, so that turning a bolt from the outside pulls the nutsert. I do this in places where its inconvenient to have a bolt-and-nut, which requires two hands to tighten and loosen.

Nutserts can be ordered from Fastenal, but their minimum order is a box of 25. When I only need a few, I order from McMaster-Carr. Click on the link, scroll down to "Rivet-Nuts", click on that, and then select the style you want. I prefer the "Open-End Knurled Rivet Nuts", available in aluminum/steel/Stainless-Steel...metric and inches.

I use the M6 metric threads, similar in size to a 1/4" bolt.

http://www.mcmaster.com/#threaded-inserts/=bsx98t

http://www.fastenal.com/web/search/prod ... 4y6x&Nty=0
http://www.fastenal.com/web/products/de ... 653&ucst=t

Image

If you are drilling a hole in aluminum, and then epoxying a steel threaded device into the hole, another option instead of nutserts/rivnuts, is called a "thumb-nut", available from McMaster-Carr: http://www.mcmaster.com/#thumb-screw-nuts/=mm9wyc

Image

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