Using cross nuts and hex nuts is a smart way to attach structural stuff to your van’s walls and ceiling: It prevents rust in the long term, and it provides very strong anchor points for structural stuff (such as cabinets). Sounds promising, doesn’t it? Keep reading to learn how to choose the correct cross nut and hex nut size and how to install them!
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1- Using Sheet Metal Screws
Screwing stuff directly into the van is fast & easy, so why even bother using cross nuts in the first place? Like everything in life, the fast & easy solution often isn’t the best solution… Here are the potential problems from using sheet metal screws:
Look carefully: there is no unpainted surfaces in a van. Paint has a much bigger role than just being pretty: it protects the metal from rust. The action of screwing, drilling a hole, or cutting metal removes the paint and the bare edge now becomes a potential ignition point for rust that will eventually propagate.
The action of drilling or cutting metal will inevitably spread tiny metal chips around the work area; it’s possible to try to catch them, but only to a certain extent. Each metal chip that’s left on a surface is a potential ignition point for rust on that surface.
Modern vans are a bit finicky… make sure to follow the no-drill zones of your van. Such guidelines are normally provided by the manufacturer:
Sheet metal thickness is around 0.032″ in a van… that doesn’t provide much grip for screws (not many threads are engaged in the metal). You’ll need a lot of screws to provide enough strength against vibration or accident.
2- Cross Nut & Hex Nut Benefits
A Cross Nut, or an Hex Nut, is an insert that is installed into an non-threaded hole; it can be an existing hole (factory) or a new hole (drilled). Once installed, it is then possible to insert a bolt into the Cross Nut/Hex Nut. Note that the Cross Nut/Hex Nut is installed permanently into the van, but the bolt can be removed and re-installed. Because of their shape, Hex Nuts cannot rotate once installed:
Fits into round holes:
Fits into hex holes:
Here is what's going on:
Cross Nut and Hex Nut Benefits:
Cross Nuts / Hex Nuts can be installed in existing holes (from factory); that means there is no need to drill new holes (and thereby exposing bare metal) for most of the conversion.
A Cross Nut/Hex Nut has an impressive pullout strength: 1215lbs (for 0.030″ thick steel) VS < 100lbs for a sheet metal screw…
Wide Grip Range
The same Cross Nut/Hex Nut can be installed in a wide range of material thickness. For example, the 1/4-20 Cross Nut can be installed in metal thickness ranging from 0.020″ up to 0.280″.
Cross Nuts/Hex Nuts can be installed even if you don’t have access to the other side of the panel (as opposed to a bolt, where you need to hold the nut on the other side).
Cross Nuts/Hex Nuts can be installed in metal but also in softer materials like wood or plastic.
3- Choosing Cross Nut and Hex Nut Size
To choose the correct Cross Nut or Hex Nut, there are 3 variables to account for:
This is the diameter of the hole receiving the cross nut/hex nut. In other words, the diameter of the hole in the van. The most accurate way to measure a hole diameter is by using a digital caliper:
This is the material thickness of the hole receiving the cross nut/hex nut. Again, a digital caliper is the most accurate way to measure this. The thickness is generally around 0.032" for the Transit.
This is the diameter & pitch of the bolt you plan on inserting into the cross nut/hex nut. For example, a 1/4-20 bolt means 1/4" diameter and 20 threads per inch (TPI). The thread of the cross nut/hex nut has to match the thread of the bolt.
4- How To Install Cross Nuts and Hex Nuts
4.2- DIY Installation
After installing 80+ Cross Nuts the DIY way, we wish we had bought the tool above… we probably spent as much in bolts & K-Nuts than the cost of the tool itself! Unless you’re almost done with your conversion, do yourself a favor and get the tool! But here’s how you can do it anyway…
- Carriage bolt (same type as your Cross Nut. 1/4-20 Cross Nut = 1/4-20 bolt. Buy from Amazon)
- K-Nut (it’s a nut with an attached, free spinning washer. Buy from Amazon). We found this type of nut will last MUCH longer than a regular nut (a regular nut will last for 1-2 uses only as opposed to 10-15 uses for the K-Nut)
- Box Wrench (or any drilled plate would do. This is just to prevent the Cross Nut from rotating when upsetting)
- Vise Grip (Buy from Amazon)
- Wrench (for turning the K-Nut)
1- Find a hole...
2- Insert the Cross Nut in the hole
3- Insert the box wrench, k-nut, and carriage bolt, and secure the vise-grip to the carriage bolt.
5- Remove the box wrench, k-nut, and carriage bolt. That’s it!
6- Bolt stuff into the cross nut!
5- Installation Tips
5.1- How To Transfer A Hole Pattern
Now imagine you have to install a cabinet using 4 cross nuts. You install the 4 cross nuts into the van first and that creates a “pattern”. You must replicate this pattern in your cabinet, so the holes in the cabinet align perfectly with the cross nut locations. Here is what we did:
3- Then we pressed the cabinet’s panel against the hanger bolts sharp end (all of them at once). This transfers the cross nut pattern from the van’s wall onto the cabinet.
4- We removed the cabinet and drilled a hole at each cross nut locations.
6- On Second Thought...
Installing cross nuts is definitely more time consuming and complicated than screwing directly through the metal, but unless you’re converting an old rusty van, it will protect your investment in the long run, AND it is stronger and safer. There is nothing like having the feeling you accomplished things the right way! 🙂
Nice To Meet You.
Hello! We’re Isabelle and Antoine In 2017, we sold our house (and everything in it), quit our engineering careers, and moved into our self-built campervan. We’ve been on the road since then, and every day is an opportunity for a new adventure; we’re chasing our dreams, and hopefully it inspires others to do the same!