Oak desk chair repair

[NewatThis]

New to forum, so hopefully I'm posting in the right location! 

I've got an old oak desk chair that were bought in Kansas probably 40 years ago.  It was old then, but I don't really know how old it is altogether.  Anyway, it's served us well all this time until, a couple months ago, I was leaning (too far!) back in it and had multiple splits in the wood, depositing me unceremoniously onto the floor.  While we've (my wife and I) done a fair amount of refinishing, and carpentry around the house, furniture work is totally new to me.  As a result, my first reaction was to throw in the towel and just pitch the chair.  But I couldn't bring myself to throw it out.  So now, a couple months later, I've decided to try a repair.  

I'm sure there are more "appropriate" ways to do what I'm doing, but I decided to do much of the repair with glue and some long bronze JCBW screws and glue.  While I think that approach will hold things together, I'm worried that if/when someone leans too far back, it'll give way.  Problem is, the chair is one in which the seat and the back are joined at a 90 degree angle but have zero additional angled supports to resist the force of someone leaning back.  I've looked online at what are apparently called "hip hugger braces" and the selection is slim.  And the more significant problem with that approach is this:  The chair back is curved, so braces applied to the two outer vertical supports of the back are going to be angled inward and attach to the seat of the chair well inside the outer edge.  (You can kind of see what I'm talking about by looking at the included pic of the one split piece that still needs gluing.  It roughly shows where the braces I'm talking about would go.) 

You can also see the tops of some of the bronze screws that help affix the back of the chair to the seat—that piece of wood that the screws tighten down onto had split lengthwise when the chair imploded on me.  You can't see it in this pic, but I've also got 2 longer versions (70 mm) of the screws going into the back of the outside vertical back supports forward into the seat itself.  Between them and glue, I would think it would be fairly strong, but I'm not positive it'll be quite strong enough.   

So I guess my question is whether there is a relatively straight forward way of accomplishing this (ie inserting a brace between the seat and the back—or otherwise adding support to the back to counter the force of someone leaning back)?  Do folks ever use something pliable (leather straps?) to achieve this kind of support?

[wtnhighlander]

If you can post pics from a few different angles, it will help a lot. Looks like the vertical split occurred where the notch around the seat created a weak spot. Ideally, that vertical member should be replaced, but some PVA wood glue can fasten it with near the strength of the wood lignin. More data is needed to provide good advice on the overall repair.

[NewatThis]

The only other two "exploded" views I have, with the (not-yet glued) assembled chair disassembled.  

 

 

 

[wtnhighlander]

It appears that the vertical members at each side of the back were doweled to the wide 'strap' across the back of the seat, then the assembly was doweled and screwed to the back edge of the seat platform. If it is possible to remove that 'strap' component, a pretty good repair seems possible, but that might be difficult if it is also glued in place. Have you tried removing those 2 plugs to get at the screws?

Does this chair have a pedestal base, maybe with casters?

[NewatThis]

On 9/8/2023 at 9:14 PM, wtnhighlander said:

It appears that the vertical members at each side of the back were doweled to the wide 'strap' across the back of the seat, then the assembly was doweled and screwed to the back edge of the seat platform. If it is possible to remove that 'strap' component, a pretty good repair seems possible, but that might be difficult if it is also glued in place. Have you tried removing those 2 plugs to get at the screws?

I haven't.  Like I indicated, I'll work with 2x4s, planks, plywood, etc, but (other than simple glue fixes) really don't have much/any experience in furniture repair.  Those plugs: would I sharp-chisel them off?  Would they pry?  I really don't even know if there would be screws or more dowels behind them.  I have a feeling the 'strap' wood is glued, but I certainly don't know that for sure.  And, if I wanted to replace that strap piece (a good idea, I suspect), I'm not even sure how I'd source it, match it to what's there, curve it (I assume soaking in water would be involved?), etc.  All of which is why I (most unprofessionally, no doubt) opted for placing those big screws vertically.

My mindset was this: I like the chair. I hated to just throw it out. Figured I'd try to do something functional and, hopefully, not-too-ugly to effect a repair, knowing full well I may or may not be successful.

On 9/8/2023 at 9:14 PM, wtnhighlander said:

Does this chair have a pedestal base, maybe with casters?

Yep, see photo.  (Rufus was posing so nicely for me I decided I had to include him!)

 

[wtnhighlander]

Assuming you have limited tools and woodworking skill / experience, here is my suggestion (requires a drill, small saw, maybe a chisel, and some tape or clamps).

With the back removed, apply a thin layer of PVA wood glue, like Titebond 2, to the surfaces of the split-off piece, and nest the split grain back together. Wrap it with masking tape, or otherwise clamp it together to dry. The joint will be very strong if you fit the split grain together well.

Once the glue dries, saw away the remains of all those dowels, and scrape away all the old glue from the mating surfaces. Then glue dowel segments into the holes where the old dowels pulled out, and trim them flush.

Fit the back into place, with notches held tightly agsinst the sear edge. I would drill through the back of each vertical member, into the center of the seat plank, and install a long (3" or more) washer head screw. If space allows, drill from the sides, into that 'strap' component, going perpendicular to the first screw, one above it and one below it. Unless there is more material than it appears in the photos, these cross screws should be smaller in diameter, flat-heat type, and counter-sunk to minimize their appearance. It won't hurt to use wood glue in the notches before adding screws, but due to the cross-grain orientation, the added strength will be minimal.

Don't over do it on the screws. Three in each side, as I described, will weaken the wood enough, as it is. Look up a hole sizing chart to determine the proper bit size for the threads of the screws you select, and use that where the threads will hold. Drill out the hole in the vertical members a bit larger for clearance, so the screw will pull tight, and won't apply a splitting force to that relativelt thin vertical member.

[NewatThis]

We're getting ready to take off for the weekend, so I'll read this more carefully when we get back.  (Just skimming it, they all look like good suggestions.  I DO have those tools for sure!)

Thanks for the input.  I'll try to remember to let you know how it goes.