Cross Nut

Crossnut-Heading-1920-px

Cross Nut

Using cross 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 size and how to install them!

Disclosure: This post contains affiliate links, which means that if you click a product link and buy anything from the merchant (Amazon, eBay, etc.) we will receive a commission fee. The price you pay remains the same, affiliate link or not.

Portrait

1- Using Sheet Metal Screws

Screwing stuff directly into the van is fast & easy, so why even bother using cross nut in the first place? Like everything in life, the fast & easy solution often isn’t the best solution… Here are the potential problems by using sheet metal screws:

RUST

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.

More Rust

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 not to a certain extend. Each metal chip that’s left on a surface is a potential ignition point for rust on that surface.

Electronics Interference

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:

Weak Strength

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 Benefits

A Cross 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. Note that the Cross Nut is installed permanently into the van, but the bolt can be removed and re-installed.

Before Installation:

PlusNut, Pre-Bulbed

After Installation:

Crossnut no Crossnut

Here is what's going on:

cross-nut-simulation

Cross Nut Benefits:

Prevent Rust

Cross Nuts can be installed in existing holes (from factory); that means there is no need to drill new holes (and therefore exposing bare metal) for most of the conversion.

High Strength

A Cross 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 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″.

Blind Installation

Cross 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).

Material

Cross Nuts can be installed in metal, but also in softer materials like wood or plastic.

3- Choosing Cross Nut Size

3.1- DIY

To choose the correct Cross Nut, there are 3 variables to account for:

Hole Diameter

This is the diameter of the hole receiving the cross 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:

Grip

This is the material thickness of the hole receiving the cross nut. Again, a digital caliper is the most accurate way to measure this.

Thread

This is the diameter & pitch of the bolt you plan on inserting into the cross nut. For example, a 1/4-20 bolt means 1/4" diameter and 20 threads per inch (TPI). The thread of the cross nut has to match the thread of the bolt.

Cross Nut Buy Links

crossnut
HOLE DIAMETERGRIP
THREADBUY LINK
minmaxminmax  
0.312″0.317″0.020″0.175″10-32Amazon
0.386″0.391″0.020″0.280″1/4-20Amazon
0.484″0.489″0.020″0.280″5/16-18Amazon
0.562″0.569″0.020″0.280″3/8-16Amazon

3.2- Cross Nut for the Ford Transit

Ford Transit Medium Roof Medium Length White Iso
HOLE DIAMETER GRIP THREAD BUY LINK
min max min max
0.386″ 0.391″ 0.020″ 0.280″ 1/4-20 Amazon
0.484″ 0.489″ 0.020″ 0.280″ 5/16-18 Amazon
*BOLD = MORE COMMON.

3.3- Cross Nut for the Sprinter

Mercedes Sprinter Van
HOLE DIAMETER GRIP THREAD BUY LINK
min max min max
0.312″ 0.317″ 0.020″ 0.175″ 10-32 Amazon
0.386″ 0.391″ 0.020″ 0.280″ 1/4-20 Amazon
0.484″ 0.489 0.020″ 0.280″ 5/16-18 Amazon
*BOLD = MORE COMMON.

3.4- Cross Nut for the ProMaster

Ram Promaster
HOLE DIAMETERGRIPTHREADBUY LINK
minmaxminmax  
0.312″0.317″0.020″0.175″10-32Amazon
0.484″0.489″0.020″0.280″5/16-18Amazon

4- How To Intall Cross Nut

4.1- Using A Cross Nut Tool

This will save you time and trouble. Trust us, we installed all our cross nuts without tool and we wish we invested in the proper tool…

Astro 1450 Cross Nut Tool

4.2- DIY Installation

After installing 80+ Cross Nuts the DIY way, we wish we bought the tool above… we probably spent as mush in bolts & K-Nuts than the cost of the tool itself! Unless you’re almost done with your conversion, make yourself a favor and get the tool! But here’s how you can do it anyway…

Tools required:

  1. Carriage bolt (same type as your Cross Nut. 1/4-20 Cross Nut = 1/4-20 bolt. Buy from Amazon)
  2. 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)
  3. Box Wrench (or any drilled plate would do. This is just to prevent the Cross Nut from rotating when upsetting)
  4. Vise Grip (Buy from Amazon)
  5. Wrench (for turning the K-Nut)

1- Find a hole...

plusnut-demo-step-1

2- Insert the Cross Nut in the hole

plusnut-demo-step-2

3- Insert the box wrench, k-nut, carriage bolt and secure the vise-grip to the carriage bolt.

stackup

4- Upset

plusnut-upset

5- Remove the box wrench, k-nut and carriage bolt. That’s it!

plusnut-front-view

6- Bolt stuff into the cross nut!

plusnut-example

5- Installation Tips

5.1- How To Transfer A Holes 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 into your cabinet, so the holes into the cabinet align perfectly with the cross nut locations. Here is what we did:

1- We got a bunch of hanger bolts:

Hanger Bolts

The hanger bolts you buy must be the same thread as your cross nut!

2- We installed a hanger bolt in each cross nut, sharp end pointing out:

3- Then we pressed the cabinet’s panel against the hanger bolts sharp end (all of them at once). This transfers the cross nuts pattern from the van’s wall onto the cabinet.

4- We removed the cabinet and drilled a hole at each cross nut location.

5- We put the cabinet back in place and bolted it through the holes we previously drilled into the cross nuts. Voilà!

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! 🙂

STAY IN TOUCH!

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about us

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!

95 thoughts on “Cross Nut”

  1. Hey guys, awesome read (as always)! Question : When the heack do you install the crossnuts? Before or after insulation? Thanks in advance for the reply! 🙂

    Reply
    • You can install the Thinsulate first, since you won’t cover the frames with it (where you’ll install the crossnut). Then crossnuts and EZ cool (see our build journal).

      Cheers

      Reply
  2. When I installed a cross nut there is a small gap? It doesn’t seem to sit flush with the vans sheet metal, is this normal? There is an area on the back side of the cross nut that is slightly larger than the holes diameter which is preventing the cross nut from sitting flush.

    Reply
  3. Have you or anyone found a source for these crossnuts for the transit in Canada?
    The shipping is almost the same as the cost of the crossnuts.

    Reply
  4. Just bought some cross nuts using your link (couldn’t do the same for the tool because Amazon didn’t have any). Thanks for this amazing website which has provided me so much useful information as I’ve progressed with my build.

    Reply
  5. I Use the new Astro 1450 to set cross nuts, also drill linked to extraction nob to speed up removal of mandrel from set cross nut …. installed a bag of 50 in less then 2 hours

    Reply
  6. Thanks for the links to the plus nuts and the tool to install them. There were many reviews that said the tool seized up after installing just a few nuts so I was nervous about this
    . A helpful suggestion from a reader on the DIY Cargo Van Conversion Facebook page recommended using an anti-seize product. I bought Permatex and with a little practice, found the plus nuts easy to install.

    Reply
  7. Question about the hanging bolts, did you buy 80+ for every crossnut , then remove them and use a separate bolt to hang the walls?

    Reply
  8. Hi Antoine,

    Can you please link to the type of bolts and length you used for this plus nut? (I have a Ram Promaster 1500)

    Thank you!

    Reply
  9. Just starting my van build. Want to attach plywood using rivnuts to existing holes in floor. But REALLY struggled. Took all my strength yet never could never get one to seat properly. Do cross nuts require the same amount of force to attach? Thanks in advance for any help.

    Reply
    • They require a “reasonable” amount of force… it’s fairly easy to do with the tool or the DIY way. Some people use a little bit of lubricant on the threads to make it easier.

      Have a good one!

      Reply
  10. Just out of curiosity, did you look into using rivet nuts instead of cross nuts? It seems like rivet nuts would be easier to install?

    Reply
  11. Hi Antoine,

    Two things:

    1. Another way to mark hole locations that I have used often in the past and now as well is to cover the end of any bolt with dry erase marker ink and push your board/cabinet/plywood against it. That ink transfers nicely. If you think you messed up, you can rub the ink off the wood and do it again.

    One nice thing is that you can get closer to the wall and if a bolt is not marking because you need a shim, you can screw the bolt out a bit, and get the shim thickness.

    2. I actually had to drill a few holes in the van to accept some cross nuts. Is that ironic or something? Idid paint but didn’t sand first.

    Cheers, Don

    Reply
  12. Antoine,

    I haven’t read read all of the comments, but a word to the wise:

    Make sure you test the cross nut before putting your bolt in and having the cross nut rotate with the bolt. Unless you can get a pliers on the back of the cross nut, which sometimes you can, you are not getting that bolt out!!! (Sometimes you can get a knife between the van metal and the inside edge of the cross nut to stop its movement.)

    One easy test is use the vise grip to rotate the setting device out of the crosscut while it is under full tension (after setting the cross nut). If it rotates, you are not done. Tighten some more!!

    Cheers, Don

    Reply
  13. Thank you for your hard work producing this step by step problem solver website. You have inspired me to get back on the DIY build out of my 2010 Sprinter

    Reply
  14. I refer folks to your site a lot on the various forums. I have used your ideas and links to build out my van. The DIY for the cross nuts can be done in a simpler manner using a star washer, closed end of a wrench, washer, bolt. You attach to the cross nut then collapse the nut using either a wrench, rachet or an impact driver. I have loaded the video to IG under jimmcneill1978 if you want to check it out.

    Reply
  15. I have a T-350 Passenger van HR and I would like to run two Unistruts along the ceiling to support a suspended bed, but of course I cannot see the van structure because of the trim. I looked inside a cargo van at a local dealer and looked at the existing holes in the Transit ceiling supports. I want the unistruts to be about 20″ off center. Which holes in the existing trusses should I use – and with which cross nuts?

    Thank you for your extensive information.

    Reply
    • We didn’t use the smaller holes, but you could measure the diameter and find the appropriate crossnut using the table in this page. Sorry we can’t measure ours because of our wood paneling 🙂

      Cheers!

      Reply
  16. Thanks for all the info. But I’m a bit confused about using the plusnuts. If the walls/ribs are covered with insulation and EZCool, how do you know where the holes or plusnuts are? Do you cut holes in the EZCool as you go along, to expose the plusnuts? Or do you install the plusnuts after you put up the EZCool? I also assumed the wall paneling would go up behind the cupboards, but that would also cover up the plusnuts. Do you just try to mark where the plusnuts are, so you can find them later when you mount the cupboards? Thanks for the help!

    Reply
    • The Cross Nuts are installed first. When it’s time to add the insulation, we installed hanger bolts into the plusnut and we poked through the insulation, so you know where the Cross Nuts are (you can use a red sharpie to make it even more obvious, before removing the hanger bolts).

      Our wood paneling does not go behind the cupboards, but you could use the hanger bolts method if that’s what you want.

      Hope that make sense!

      Reply
  17. Re: PlusNuts

    If you live in Canada, it’s very hard to find the prebulbed PlusNuts (or very costly), and the ones on your Amazon.com won’t deliver to Canada. Since it is 840km return to nowhere Montana, I ordered many 1/4-20 rivnuts at Amazon.ca ahead of my van delivery. Just before starting on the bed frame, I tried inserting one, and much to my chagrin, it did not fit!

    Using a digital measuring device, I found that the hole size was 0.367″. Therefore, the PlusNuts shown in your chart would not fit either. Perhaps Ford has changed the hole size in the 2018 models. I ordered new rivnuts that are 0.348″, and they fit. Just wanted to make people aware to measure first, and order carefully.
    Not a big $$ deal – just a hassle.

    Reply
    • Hi,
      Unfortunately I can’t confirm if the hole size have changed since 2016 🙁
      Have you read this thread here: FordTransitUSA Thread
      It’s about someone that has the same issue as you, then finally: “Yep, found I could ‘persuade’ the plusnuts into the (majority) slightly smaller holes. Just tapped them with a mallet or even my hand. Don’t believe the paint is damaged in these scenarios.”

      Have you try to “persuade” them with a hammer?

      Reply

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