I am trying to build storage for a panel van. My problem is how to make use of pre-existing holes for attaching bolts to. The loading space in the van has vertical structural beams which have holes that I would like to use to secure the storage. The holes are shaped something like this:

enter image description here

It is not easy to reach behind those holes - basically only via other similar holes some distance apart. Otherwise I might have used a particularly large penny washer and put a bolt through it. The distance behind the holes to the van's external panels is approx 25-35mm depending on location.

Is there a trick that professionals use to attach things to these holes? I presume that's what these holes are for in the first place?

The only alternative I can think of is drilling new holes and using a tap to thread them to accept a bolt directly.

Edit: Thank you for everyone's suggestions/answers. Lots of fresh ideas which I will pick out bits of and combine for my solution. Could not choose an individual answer, so up-voted all helpful contributing answers!

  • What type of storage units are you trying to attach? Shelves or a cubical that will sit on the floor and attached to the wall only to prevent tipping?
    – mikes
    Mar 24, 2015 at 10:43
  • More or less. A large aluminium frame which will need plywood shelves and some plywood walls to give it rigidity. The aluminium frame will be 1 1/4" square hollow aluminium. That structure will be held to the van using U-brackets which will first be bolted to the van, then the square frame sections will be bolted onto those U-brackets which fit snugly over them. Why do you ask? As well as preventing tipping, it will have to handle all sorts of forces from acceleration, breaking, bumps in the road and so on...
    – Jodes
    Mar 24, 2015 at 11:00
  • If you are attaching free hanging bins to the wall the hardware must support the weight vertically. If the frame sits on the floor it will be holding the weight and the wall anchors merely hold it in place.
    – mikes
    Mar 24, 2015 at 11:21
  • Pictures, please. This sounds strikingly like uni-strut, in which case there would be nuts that could be slipped inside the "beam."
    – Ecnerwal
    Mar 24, 2015 at 12:18
  • 1
    Check to see if the Van manufacturer provides clip-nuts (caged nut with a clip that holds them in that oval hole) for attaching items. It sounds like the vehicle is made from the factory for custom attachment of equipment. Mar 24, 2015 at 18:21

4 Answers 4


Find a bolt with a similarly sized and shaped head that can go in through the hole, then turn 90°. Tighten it in place with a washer and bolt on the inside of the van to lock the bolt to the van. Everything else then bolts to these.

If you can't find suitably shaped, oval headed bolts, a 30mm round bolt head or a smaller bolt plus a washer could be ground down to the oval shape.

The advantage here is that you're not putting additional holes in your sheet metal which opens it up for the potential of rust.


If you could find them with a head size that's just right, you could use something like toilet flange bolts. Where the head of the bolt is ovular, and could be turned once in the hole.

Toilet Flange Bolts


This is sort of a modification of what @FreeMan said, but what I would suggest is you get bolts with flat washers, where the flat washer is less than 20mm diameter so it will fit through the hole. The head of the bolt will need to be smaller than the flat washer (obviously). You will need six pieces total per mounting bolt, including the bolt itself. Put them together in this order: bolt, flat washer, flat washer, (supported structure), flat washer, lock (or split) washer, non-self locking nut. The bolt itself will need to be long enough to accommodate whatever you are going to mount to the vertical structural beams. It would look something like this when put together on the beam:

enter image description here

(NOTE: This is a quick PowerPoint rendering and is not to scale by any means.)

The idea here is to use the bottom half of the washers to grab the wall support. About 1/3 of the washers would be grabbing the wall support, but this will be more than enough to hold it in place. Of course, you'd want to choose the correct length of bolt so it doesn't protrude very far. The lock washer is there so you can tighten the bolt from the nut end without the need for a wrench on the other end, and so it will stay put once it's tightened. If you find that the bolt still moves without a wrench on the other end, you can put a lock washer between the bolt head and the flat washer, but I've found on blind holes like this, if you just hold the threaded end of the bolt with your fingers and use an open ended wrench to turn the nut, the bolt will tighten down without issues. If this is a permanent fixture, you could also put thread locker on the nut to ensure it stays put.

EDIT NOTE: If you are looking for added holding power, move the bolt to the left or right in the hole. This will provide the side and bottom of the hole for something the bolt/washer/nut can hold onto.

  • 1
    My solution would have an additional nut between the "Supported Structure" and the flat washer on the "inside" of the van, but yeah, you drew what I was thinking (you and your fancy PowerPoint!). I think the advantage of a larger washer cut or ground down to fit the shape is that it grabs the top of hole as well as the bottom for a bit more secure hold. The need for that may be determined by how much weight will be held, how many holes are available for support and how aggressive the driver(s) may be.
    – FreeMan
    Mar 24, 2015 at 13:07
  • How would you keep the bolt from spinning, while you try to tighten the nut?
    – Tester101
    Mar 24, 2015 at 13:20
  • @Tester101 ... I've done it a hundred times. All you have to have is a little bit of pulling pressure while you are tightening the nut and it will cinch down. If you find you cannot get it started to cinch down, place a screwdriver behind the first flat nut and then cinch it down. This is the reason you use non-polylock (normal) nuts. It works slick as you want it to. It's the friction at the head of the bolt which allows this to happen. Mar 24, 2015 at 14:36
  • @FreeMan - Remember it isn't the bolt/nut which holds the piece in place, it's the friction between the supported structure and the vertical structural beam which does. The bolt/nut creates the friction. Mar 24, 2015 at 14:38

If this is a custom (read home made) set up the way it is typically done is to attach either furring strips or 3/4" panels to the ribs or frame supports. Use self tapping sheet metal screws to attach the wood to the walls. Then use what ever fastener is appropriate to anchor the shelves to the wood. After reading you comments, can you drill a pair of horizontal holes in the frame/rib. Then get the "U" bolt thru both holes and clamp it around the square tubing?

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