OtterBox Defender

Posted by Jonathan on August 4, 2009 in Projects, Tripod Mount |

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What Parts do you need to modify a OtterBox Defender:

NOTE: A lot of the parts at McMaster-Carr are sold in Quantities. You usually can not just buy one or two of a item from them.

(1) Weld Nut with Holes 1/4″-20 thread size.

I bought mine from McMaster-Carr. Part Number “90611A350”

These are plain steel, a stainless steel might be better so they don’t rust as easy.


(3) 1/8” Blind CounterSunk Rivets

(I got these at Home Depot)

You can get them at McMaster-Carr. Part Number “97525A665”


Tools I used with Modifying the OtterBox Defender:

  • An 1/8” Drill Bit
  • A Drill bit with a diameter a little bigger than .300”, a 5/16” bit will be perfect if your holes are drilled with tight tolerances.
  • A Vise
  • A Punch to punch out the Silicone. I made one from a weld nut and just ground it down to make it sharp.
  • A Rivet Gun
  • A Cordless Drill
  • A Countersink set, a 1/4” to 1” set should do.
  • A metal file. Any length should do. A 6″ or 8″ bastard file is what I used.
  • An xacto knife set can help with some of the plastic work.
  • A regular 1/4″-20 bolt with 2 or 3 nuts. The bolt can be 1 inch to 3 inches.
  • A 1/4”-20 tap is Semi-Optional. It makes it easier when you grind down the weld nut. (A tap re-threads messed up threads)
  • A Belt Sander is Optional but makes quick work of some of the tasks.

Below you will find pictures of all the tools I used. Not all the tools were used from the pictures that have more than one tool in them.

How to mod your OtterBox Defender to incorporate a tripod mount:

Safety: Always wear glasses of some type with drilling/cutting/grinding metal and plastic. Safety glasses are the best to wear since they are usually made of a hard plastic, but anything to protect your eyes is better than nothing.

Step One- Prepare the Parts

  1. Take your rivets and put the head in the end of a cordless drill (this will in effect make the drill a lathe) and using a Dremel locked in a vise or a belt grinder sand/grind the countersunk end of the rivet to a smaller diameter and thickness.
  2. (This part is way easier to watch in my video than explain in writing) Take your weld nut and put it on a 1/4”-20 bolt, lock it onto the bolt with a regular 1/4”-20 nut. Grind the base of the weld nut down by about 50-60 percent. You want enough room to countersink it but make it thin enough to sit beneath the rubber in the case. Use water to cool it down, don’t let it get too hot
  3. Turn the weld nut around on the bolt and grind down the stem on the weld nut by about 30-40 percent. Use water to cool it down, don’t let it get too hot. This is where you need to re-thread the nut with the thread tap. You might have to do this or not depending on how you grind the stem down. You could use a 1/4”-20 bolt to try and re-tap the threads. (See my videos for more chat about this)
  4. Grind the edge of the stem to have a slight taper to make it a dull edge and not sharp at all.
  5. Take the weld nut and using a Dremel with around a 1/16″ drill bit/cutting bit expand the three outer holes of the weld nut inward. In the end they need to be about 1/8” in diameter to allow the rivets to go through them. You can not just use a 1/8″ drill bit and drill through the holes as they are not in the center of the ring of metal  that surrounds the weld nut. They are too close to the edge. Lock the nut in a vise REALLY good to do this, (see my videos on how to do this).
  6. Clean up any burrs on the weld nut with a file.
  7. Countersink the three 1/8” holes of the weld nut on the side that the stem IS protruding from.

Step Two- Prepare the Case

  1. Find a place on the outer piece of rubber where you want the weld nut to protrude from. I chose the middle of the O in Otterbox to make it look cool. One you find that spot punch a round hole about .300 in diameter in that spot. (Don’t have the silicone part on the plastic case at the time)
  2. Put the weld nut through the silicone part of the case and then put the case back together(You don’t have to have the iPhone in it). Mark the middle of the spot the weld nut touches the plastic portion of the case with a sharpie.
  3. Take the silicone part of the case off the case and take the case back apart.
  4. Line up the weld nut on the outside of the case using the mark you just made. Take a 1/8” Drill bit and drill the three holes for the rivets through the smaller three holes on the weld nut. I stuck a rivet through a hole every time I drilled one to keep the weld nut in place and make aligning the holes easier.
  5. Countersink these holes on the plastic on the inside of the case. Do not countersink too far as you need some plastic for the rivets to grab onto. Countersink the hole a little more than the rivet head needs, you want the rivet head to sit below the plastic so it can’t touch your phone.  If you think you will need to countersink too deep into the plastic,  go back and make the rivet heads smaller. This plastic is pretty thick so you got more to work with than some of the other case mods I’ve done.
  6. Test placing your rivets through the case to make sure the rivet heads will sit a little below the plastic, if they are flush or above the plastic they could touch and scratch your phone.
  7. Clean up the inside and outside of the case around the area you are working on.

Step Three- Assembly

  1. Stick the weld nut on the outside of the case lining up all three of the rivet holes
  2. Put a rivet through the case and then the weld nut. So you are sticking the rivet from the inside of the case to the outside of the case. Using your rivet gun squeeze so the rivet grabs the weld nut and tightens. DO NOT squeeze the gun all the way.
  3. Place all 3 rivets and tighten them. The rivets should be filling out the countersinks you made in the weld nut. I personally just tightened the rivets enough to feel really secure but not pop the rivet shanks.
  4. Remove the rivet shanks.
  5. Now this part will take some time, using a grind wheel attachment on the Dremel grind down the rivet heads on the outside of the case to be flush with the weld nut. Make sure you don’t let the metal get too hot, use water to cool the parts down.
  6. Clean up your tools and mess. The case is going to be VERY dirty from all that grinding so make sure to wash it out good. You are now done.

Related Videos:

This video is a uncut version of my video tutorial on this case.

Download Otterbox Defender- M4V Format

To Download: Right Click – Then Click “Save Link As”

Its run time is 54:19 and its file size is 648.9mb.

I will be adding a edited/cut down version that is short enough for youtube in the near future. I will update this post when I finish that video.

This video shows you how to make a home made belt grinder/sander.

Download Home Made Belt Sander- M4V Format

To Download: Right Click – Then Click “Save Link As”

Its run time is 02:17 and its file size is 26.39mb.

Optional Step:

I had some Liquid Titanium laying around (it’s used to fill gaps in metal shafts for repairing and then machining them), so I mixed up a very small amount and I placed it in a syringe from the plunger side. A common product to use that is similar would be J-B Weld.


(McMaster-Carr part Number “7510A653”)

I then squeezed some of it into each of the rivet holes and used a small piece of metal (like a squeegee) to even it out on both sides of the rivet holes. I let it dry and I then used my Dremel to grind down any excess. It makes the mod look nicer and adds a little more strength.


Finished Product:

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