Removing the "non-removable" arms on a Herman-Miller Aerontm chair without damage is possible...but it's not easy.


I made this page because I removed the arms from my chair and found it insanely, ridiculously difficult. And when I typed "remove arms" into Google, it suggested "from Aeron chair" as the first choice! So apparently this is a common problem. H-M claims that the lever-adjust arms are non-removable, and for the non-mechanically-inclined, they might as well be. (If your arms adjust with a thumbscrew, contact H-M for removal instructions.) But with basic tools and mechanical aptitude, even the lever-style arms can be removed.

Of course, I accept not even the teensy, tinsiest bit of responsibility for your hurting yourself or your chair by doing as I describe below. Take appropriate safety precautions, and don't try this unless you're familiar with the types of tasks described.

The arm lock design is a perfect storm of excessively strong thread-locking compound, an endless-step cam (instead of one with positive stops), and delicate aluminum and plastic parts. Other than actually epoxying the whole thing together, H-M couldn't have made it much more difficult to disassemble...which means it's also impossible to recycle. (I'd expect better from one of the premier design houses in America, but I digress.) Here's what to do:

Method #1 (non-destructive, but often doesn't work)

  1. Remove the back of the chair so you can access the machine screw holding the arm on.
  2. Block the cam so you can apply enough torque to overcome the threadlocking compound. To do this, wedge pennies or other flat metal objects between the lever and the outboard side of the groove the lever sits in. This needs to be very tight to have any chance of working.
  3. If you happen to have a micro-flame torch (like those used for Creme Brulee), heating the screw head as hot as you can without melting any plastic parts will weaken the threadlocking compound and make removal much easier.
  4. The screw requires a T-27 Torx bit. Thanks to the threadlocker, you'll need to apply serious torque, so get a 1/4" wrench or socket -- a screwdriver-style Torx driver won't cut it here. Also note that the thread on the left-side arm is left-handed, so loosen in the opposite direction as normal.

The success of this method depends on how well you're able to do steps #2 and #3. If the mechanism repeatedly "gives" as you're turning (versus continuous resistance), this method is not going to work for you. STOP (to avoid damaging the cam) and use the method below.

Method #2 (brute-force, but always works)

  1. Remove the back of the chair so you can access the machine screw holding the arm on.
  2. Make a note of the stack of washers and other parts, as these will fall off in step #4.
  3. Using progressively-larger metal drill bits, drill off the head of the screw. I found that a 1/8"-3/8"-1/4"-3/8" progression worked well with my cordless drill. (This sounds like a huge pain, but it actually takes only five minutes or so with cobalt drill bits, available at most hardware stores.)
  4. When drilling with the 3/8" bit, hold the arm securely -- once the bolt head comes off, the arm will be free.

If you never want to put the arms back on, you're done. Otherwise, since you just destroyed the bolt that holds the arm on, here's what to do next:

  1. Wedge two pennies between the lever and the outside of the chair frame to immobilize the cam. Verify you've done this right by attempting to turn the bolt stub with pliers -- it shouldn't budge. If it spins, you must correct this before you move on.
  2. Hold the chair's arm in your hand with what's left of the bolt pointing up.
  3. Using a standard propane blowtorch, heat the TOP of the bolt -- the part furthest from the arm -- for approximately 30 seconds. The heat will travel down the bolt and soften the threadlocker without melting anything around it. If you see wisps of smoke from the lower part of the bolt, you've heated enough.
  4. Using locking pliers, grab the hot bolt and unscrew it. If it won't turn, heat the bolt further. NOTE: The left arm uses a left-hand thread.
  5. The lever and assorted bits can now fall out of the arm, so keep the parts in order.
  6. Procure replacement bolts. They're M8 fine-thread and as noted above the left arm uses a left-hand thread. Head style is up to you.
  7. When reinstalling the arm, the bolts are NOT tightened all the way. Snug up the bolt, then back it off a bit and try the lever mechanism. The tension is correct when the arm is held securely when the adjustment lever is down, but is free to move when the lever is up.
  8. (Optional) Once you get the knack for how tight to make the bolt, use a small amount of blue threadlocker on the threads to lock the position in place.

I know the above steps would benefit greatly from pictures, but I didn't want to take the time unless people actually find and use this page. I'll keep an eye on the site stats -- if it starts getting hits I'll improve it.