Fixing Another Chair

I never realized how much I rely on my office chair's arm until the thing came off. I'm not throwing out the chair for something that is this simple to fix. That would be absurd. Yet I'm sure people do just that all the time.

Here's what I did to fix it, so you can keep your chair if something similar happens.

First you have to figure out the broken item in question is constructed.The arm is attached to the back with one bolt through the back frame. It screws into a threaded insert in the arm. The arm attaches to the seat with two bolts and two threaded inserts.

Two threaded wood inserts attach arm to seat

Threaded insert

Next, figure out the root cause. I tried simply reattaching the arm but it didn't work; the threads seemed stripped. Further investigation revealed something else going on.

The bolts in the seat didn't extend out very far at all. As a result, they engaged only the first couple of threads in the inserts and those threads finally gave way.  Either the countersunk holes in the seat weren't drilled deep enough, or the bolts weren't long enough (maybe I used the wrong bolts when I assembled this thing?). Fortunately, the bolts at the back do extend far enough and fully engage the inserts.

Bolt is too short to engage threaded inserts

Finally, evaluate repair and redesign options and pick the one that best meets your needs. I could have gone through the trouble of drilling the countersunk holes deeper.  But why not just install longer bolts for a minimal cost (if you don't happen to have bolts of the right size and pitch)?

Well... that was easy.

To prevent a similar failure on the left side, I swapped those bolts too. Thread locking compound on the bolts will hopefully prevent them from backing out.

This chair has been in heavy use for five years or so.  Aside from tje finish fading in a few spots, you may have noticed that the seat (is it leather or is it naugahyde? or pleather?) is cracked and coming apart. Clear packing tape is holding it together for now, but a recover and repadding is in order. My butt will thank me.

Fixing a Chair

One of our dining chairs' seats came loose.  I guess if they still had it in stock we could've bought one. But fixing it was easy and only took me about 20 minutes.  Here's what went wrong.  The seat is attached to the chair frame with three screws in pocket holes (arrows, below).  Two of those three screws stripped loose from the wood and so the top was loose.

Arrows show pocket hole locations

I don't have a pocket hole jig, so the next best approach was to drill vertically through the 4" deep chair frame. However, the screws I have aren't long enough to go all the way through, so I needed to drill a large countersunk hole, bigger than the screw head, and drill a smaller concentric hole through which the screw shaft would pass and finally drill a small tap hole in the chair seat.  Drill stops make it easy to ensure the right depth of the larger counter sink hole.

Screws and tools required: drill bits and drill stops

Most drill bits don't have pilot bits on the end, so your best bet is to drill the small hole first and then drill the countersink using the first hole as a guide.  Or, use a Forstner bit with a spike on the tip, or as I did, a bit with a pilot tip, and use the small center hole these bits create as a guide to drill the smaller hole.  Position the chair seat, screw the screw into the chair wood a little, to create a mark, then drill the tap hole into the chair seat.  Now fasten the two parts together.  Below is the countersink hole offset from the pocket hole.

Pocket hole, top; countersink hole, bottom