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. Thanks for all the tips, tricks, and how-tos! I’ve used several. I did modify your plusnut install just a bit. I find the vice grips slip quite often and ultimately destroy the bolt.

    I simply use a 1/4 inch drive ratchet and whatever socket you need to hold the bolt as I turn the nut. Using the smaller ratchet, you can hold it and the slip wrench in one hand while you turn the nut with the other.

    Hope all is well!

    Reply
  2. Hi Antoine

    Great site! Would like to buy items via your webpage, but links to plusnuts, the plusnut tool, and other items are not working for me. Any suggestions? I’m in Canada, so that could be it.

    Reply
  3. Hey Antoine,

    The Amazon link to the plusnut seems to be a dead end… do you know of anywhere else I can order them?

    Thanks for the great posts!

    Reply
    • For the life of me, I can’t seem to make this work. Is it supposed to be super hard to turn the nut? I can’t even turn it! I can’t make the Cross nut compress at all- I’ve been trying for hours! Help!

      Reply
      • this from Antoine Nov. 16 2016….keep scrolling down…you’ll find it.

        Did you ordered the PRE-BULBED ones? The compression has been slightly started at factory, it is therefore easier for the customer to compress the plusnut. If you ordered from the link I provided, you have the pre-bulbed. Yes, the bolt should extend all the way into the Plusnut; this reduces the chance of damaging the threads since there is more surface in contact.
        I’m surprise you could not make it work using the tool It requires some torque, but not THAT much… maybe you could ask someone else to try?? Or watch some videos on youtube to make sure you do it properly? Good luck!

        Also from Antione, see Dec 21, 2017 :

        You don’t need the k-nut! It’s used just to install the Plusnut for the DIY way.
        Good day

        Therefore, if you are installing diy like it sounds, you may need the k-nuts to make the process easier.

        Reply
  4. Thanks for your tips! Do i still need to use the k-lock-nuts if I plan to purchase the recommended tool for inserting plus nuts? We have a transit as well..but the passenger van. We dont want to drill any holes at all bc of the risk of hitting air bags and wiring.
    Thanks!

    Reply
  5. I may be missing the obvious, but I’m not sure how to get the sharpened “screw” end of these hanger bolts to work. If I put the threaded end into the plusnut (sharp end out) the nut won’t screw neatly onto the sharpened end.

    If I place them the other way, the sharpened end won’t thread into the plus-nut.
    Am I missing something?

    Reply
    • The sharpened end is only used to make a mark into the object to be attached. For example, if a cabinet is hold with 4 plusnut: insert the sharpen screw into the plusnut (pointing out), press the cabinet against the 4 sharpened screws to get the plusnut pattern. Drill the 4 holes into the cabinet (where you got the marks from the screws). Remove the 4 sharpened screws from the plusnut (not needed anymore). Install the cabinet using bolts (through the holes you just drilled and into the plusnut).

      Hope that make sense!
      antoine

      Reply
    • Hi Jared,
      we primed + painted + clearcoated every hole and every trim on the van to prevent rust. It’s a new van and has many years in front of it! If you are converting an old van, it might not be necessary…

      Reply
    • Yes, same size. There is smaller holes all around the wall, I sometime wish we had smaller Plusnut as well, but we made it worked with only 1/4-20 size.

      Reply
  6. Thank you Antoine. The two stripped plusnuts happen to be located where there is no back access, a truly blind nut. One of them spins thereby eliminating the use of an oversized bit which should work on the first one. My solution for the second, spinning nut, is to use a Dremel with grinding bit that will fit inside the thread. Then carefully grind away the inside edge of the collar to separate it from the threaded portion. Hopefully, this will minimize any potential damage to the hole, i.e., paint and metal.

    As a note for future plusnut tool users, when setting the plusnut in place with the clockwise rotation of the wrench you’ll see the nut collar being drawn in against the sheet metal. Turn the nut until you have a snug tight fit. A snug tight fit does not require overwhelming force. The plusnut threads can easily be stripped or damaged with too much “brute” force. If you have trouble screwing into the plusnut, too much force was used to set it. The threads are probably distorted. This can be recovered by threading the matching screw initially with your fingers. Make sure the screw is correctly aligned and not cross threaded. Then slowly turn the screw all the way through the plusnut. There will be some initial resistance followed by a release as the screw moved through the nut. Consider using a stainless steel screw for this task. The treads are much stronger and more precise.

    Reply
  7. Wanted to thank you for the plus nut suggestion instead of drilling. Really appreciate your insight and “if we were to do it again” ideas, very helpful information.

    Wondering if you had any suggestions on how to remove a plus nut? Had a couple of Plus Nuts that stripped. The tool doesn’t thread all of the way into the nut. Have you used plus nuts for the smaller 5/16″ holes, and if so, what size plus nut would you suggest? And if I understand things correctly, this would also require another separate installation tool.

    Reply
    • Do you have access to the back of the stripped Plusnut? Maybe you could oversize-drill from the front, while preventing the plusnut rotating from the back? i have not tried this, though. I only used 1/4-20 Plusnut, using a smaller plusnut requires a different tool that matches the threads of the plusnut…
      For a 5/16 hole diameter (0.3125″), a 10-32 (grip length 0.020-0.175) plusnut should fit according to the table in this post.

      Good luck and let us know how it turns out.

      Reply
  8. Has anyone purchased plusnuts for the pre-drilled holes in the Mercedes Sprinter? If so, would love to hear if there was also a perfect-fit option out there. Thank you!

    Reply
    • We’re going to try 10-32 in our 2008 sprinter because the 1/4 really only fits into like 4 holes in the van (they are too big)

      Reply
  9. Antoine,
    First off, your van looks great! I have been using your website and awesome instructions to work on my Transit.
    Second off, I ordered the pre bulbed plus nut from the link with the factory tool and noticed that they fit easily in some holes and in others they stick out some what. I’m guessing from the bulb. Did you drive them in with a hammer to get them seated flush with the van, or did you start fastening them with it slightly protruding out of the existing hole? Thanks in advance!

    Reply
    • Hi!
      I’m glad the site is helping 🙂

      Some people drive them with a hammer, I just use the palm of my hand to push them in. In some cases, the Plusnut will not sit perfectly flush, but it’s no big deal as long as it feel solid. It depends on what you are attaching afterward i guess.

      Happy conversion!

      Reply
  10. Thanks so much for the quick reply. Yea they are the ones you recommended. turns out after some research this morning I should have ordered a rivet nut tool with longer threads. I think I will try a couple of things now (1. Get a longer bolt for the dyi method and (2. Compress the bulb just a little more in a vice first and then see if that will make things easier. Thanks again. I really like your build. Keep up the good work.

    Reply
  11. Stan, I ordered the pre bulbed plus nuts from the link above and found that I needed to add a fender washer to them inorder to keep them from spinning in the thin sheet metal of the walls of my van. Maybe they sent me the wrong size but the package says .280, not sure if that is the top out number or starting number. Once I added the washer they worked great. Good luck

    Reply
  12. I ordered the plus nuts you recommended but I cannot get them to compress. First I tried the the DYI method then I ordered the rivnut tool. In neither case was I successful in getting the plus nut to spread out. I noticed in both methods that you explained and I tried, that the threads of the dyi or the rivnut tools bolt did not extend all the way into the plusnuts threads. Do you think getting a longer bolt would help or are the plus nuts just to sturdy for my puny ways?

    Reply
    • Did you ordered the PRE-BULBED ones? The compression has been slightly started at factory, it is therefore easier for the customer to compress the plusnut. If you ordered from the link I provided, you have the pre-bulbed. Yes, the bolt should extend all the way into the Plusnut; this reduces the chance of damaging the threads since there is more surface in contact.
      I’m surprise you could not make it work using the tool 🙁 It requires some torque, but not THAT much… maybe you could ask someone else to try?? Or watch some videos on youtube to make sure you do it properly? Good luck!

      Reply
  13. Is there a reason you chose plusnuts over Heavy Duty Rivnuts? Is holding power different? Thanks for all the work you put in documenting your build, it is much appreciated.

    Reply
    • “Vis-Plus”, à St-Jérome, peut en commander mais elles ont l’air un peu cheap. Y’a peut-être des magasins spécialisés dans les vis aussi dans ton coin?

      Reply
      • Tu peux commander directement de Bollhoff Canada (situé à Markham, ON).
        J’attends des prix pour 1/4-20″ en SS. je vous tiendrais au courant des coûts vs Amazon.

        Reply
          • Pour ton information :

            J’ai récemment fait faire des simulations FEA d’un impact frontal et latéral de véhicule, avec un poids simulé de 55kg sur le toit, pour déterminer les efforts des ancrages et les specs nécessaires de la quincaillerie 1/4″-20 à utiliser, dans un contexte assez similaire.

            Résultats :
            – Wellnuts : ne répondaient pas aux efforts de l’impact. (Ultimate tensile strength autour de 360 lbf)
            – Jacknuts : ne répondaient pas aux efforts de l’impact. Quoique j’aimerais vraiment le tester personnellement. (Ultimate tensile strength 820 @ 1050 lbf)
            – Rivetnuts / Nutserts : Seules les versions métriques M6+ en acier semblaient répondre aux efforts de l’impact, et même là, c’était limite.
            – Hexsert : La version “Heavy-duty en acier de Advel répondait aux efforts sans problème. Disponible en métrique M6 à M12 seulement.
            – Plusnuts SS : La version SS répondait au besoin et pouvait pleintement résister aux efforts. J’essayerai d’obtenir l’information à savoir si la version en acier répondrait également aux efforts de cet impact.

            Donc, bon flair de ta part!

            La visserie suggérée : 1/4″20 en SS 18-8 faisait l’affaire, ça passait la simulation.
            Je me rendrai chez PMG au cours des prochaines semaines pour des “crash-tests” physiques.

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