Cracked!

[Shawn Christ]

I finished up this queen headboard in August and noticed this crack last week. It's about 4 inches long, just above the end stile, next to the right corner post.

I could squeeze glue into it but I think the assembly is too large to close the crack with clamps. So I guess that leaves a glue and sawdust mixture followed by a topcoat repair. Unless you have any other ideas.

But I'm curious, why did this happen, at this particular location? The rails are mortised into the corner posts and the panels and frames cut per spec using stile and rail cutters. There was room for expansion in these joints.

[Matt Kestenbaum]

I can think of a couple of reasons...most likely there is a cross-grain wood-movement issue. Knowing some more about the construction would help (is that a 1/4 round applied molding or a large bead cut into the rail?)

I think it only in good taste to leave the other possibility unmentioned :0 !!

[Shawn Christ]

Very funny Matt! But you raise a good point. My lovely wife didn't want a footboard so I bought a heavy duty bed frame and bolted the headboard base to it. The frame does a fair job supporting the headboard but there is definitely movement. I thought about attaching it to the wall for better support.

Those are beads cut into the face of the 3/4" rails and stiles using a standard Freud raised panel/rail/stile cutter set. Nothing fancy. Followed the instructions to allow for panel movement. I mentioned the rail mortises earlier. What other construction details would help?

[Aaron Berk]

I see what looks like allot of shrinkage going on with the whole assembly.

The edges look like unfinished wood showing through.

If it is, then I would say the glue held tight while the board shrank up and split.

Do you do like me and rush the build before the wood was ready?

[Chris Rosenberger]

I agree with Matt. The rail shrank & with the cross grain construction it could not move as it needed to so it cracked.
It also looks like the panels shrank. It looks like the humidity is to low in your house.

[Shawn Christ]

I see what looks like allot of shrinkage going on with the whole assembly.

The edges look like unfinished wood showing through.

If it is, then I would say the glue held tight while the board shrank up and split.

Do you do like me and rush the build before the wood was ready?

I noticed some shrinkage on the raised panel edges but nowhere else. I don't have a moisture meter but I sure thought the wood was ready. It sat in a guy's barn for about 12 years. Then it acclimated in my basement shop for another 2 years.

[Shawn Christ]

I agree with Matt. The rail shrank & with the cross grain construction it could not move as it needed to so it cracked.
It also looks like the panels shrank. It looks like the humidity is to low in your house.

The panels did shrink. We do have a humidifier on our forced-air furnace and the humidity level is usually around 44%. The only thing I can think of is it was very rainy and humid outside in August when I was finishing the piece in the garage. The humidity caused severe blushing to my shellac finish which thankfully was relatively easy to repair. Would that be a possible cause?

[Matt Kestenbaum]

How large were the tenons...the rails and stiles look very beefy...especially if they were broad enough to have the beads cut into them. There is a point where two smaller tenons rather than one large are less likely to create problems.

[Mac Cambra]

one other question I would ask is did you glue the raised panels in the the stile/rail assembly or allow them to float?

[Shawn Christ]

How large were the tenons...the rails and stiles look very beefy...especially if they were broad enough to have the beads cut into them. There is a point where two smaller tenons rather than one large are less likely to create problems.

The stiles are 3" wide with maybe a 1/4" face bead. All internal panels, rails, and stiles in the pic are 3/4" material. If you are referring to the stile-to-rail joint they were small stub tenons created by the bit profile, which also formed the slot for the panels. The bead continues through the profile forming the joint, similar to what you would see on most any raised cabinet door. On each end of the headboard is a 3" wide x 1.5" thick corner post which is connected to the inner panel frame by tenons at the ends of each top and bottom rail. Those tenons were much larger because the top and bottom rails were 6" wide with maybe a 4" x 1/2" thick tenon on each.

Panels are floating with only a drop of glue at the top and bottom center to keep them from rattling.

[John Coloccia]

It looks to me like everything just shrank. If you take the panel out of the equation entirely, it still just looks like everything shrank. If you imagine what happens as all the wood dries out, it will all shrink across the grain. Something's got to give at some point, and in this case it's the crack you're seeing. Seasonal changes can be huge. For example, if you're fitting drawers, you typically can fit them tightly in the summer time but you have to fit them much looser in the winter time or they just simply will not close when summer comes along.

I think having glued the stile to the the rail and the outer post set up a situation where something would have to give at some point when winter time came around. I don't build this kind of stuff normally so I don't really know. Is it normal to glue the stile to the rail and to the outer post? I would have probably chosen one or the other just on my gut feel, but maybe my instincts are off on this.

[Chris Rosenberger]

The panels did shrink. We do have a humidifier on our forced-air furnace and the humidity level is usually around 44%. The only thing I can think of is it was very rainy and humid outside in August when I was finishing the piece in the garage. The humidity caused severe blushing to my shellac finish which thankfully was relatively easy to repair. Would that be a possible cause?

I believe the cause is a lack of moisture in your house. The wood has not shrank a lot so the moisture content was not far off.
Our house has a large amount of hand made cabinets & furniture in it so we try to keep it around 50% in the winter. We know the humidity is to high when we start getting moisture on our windows. Then we back it down some.

Another issue is that you said that you have a basement shop. The humidity is normally higher in basements. The wood could have picked up some moisture when it was in your basement.

[Pat Barry]

I think your description from yesterday at 10:57PM is telling. The way I understand it you had stub tenons going into the top rail. The crack therefore happened right where the top rail was the weakest, bu the stress that caused the crack was the cross-grain situation of the top rail to the post. Likely there was no freedom for the top rail to shrink and the weakest link failed. This makes sense if you keep in mind the shape and direction of the crack, which propagates toward the weakest pathway. Question is - can you fix it? I kind of doubt you can really fix this. If you fill the crack with something now, then it will cause something else to happen - maybe further damage, when the humidity goes back to summer like conditions. I don't think this is really any sort of structural issue, although the opposite corner(s) may suffer the same problem at a later date. I would let it go and monitor it. If you are concerned about structure you may need to do something drastic to fix it. Overall I would think of it as 'character' and leave as-is. You did a really nice job on it - It looks fantastic. Would hate to see a repair make it worse. If you do decide to fill it, then consider using a latex / silicone caulk - to allow some flexibility - you should be able to color some clear caulk to make a nearlyy invisible repair.

[lowell holmes]

I'm going to take a contrarian view. I think a small hole in the end of the crack should be drilled and filled.

I would then take a sharp knife and slit the fibers in the crack to provide a continous crack to work with.

I would then prepare an appropriate sized wedge of the same specie wood and drive it into the crack (gently), glueing it in place.
After 24 hours I would pare the wedge flush and finish it. You need a small hole to isolate any stresses caused by the repair. Even if the wedge ends up being cross grain, it will not be a major distraction. Most people will not be aware of it unless you point it out.

I've repaired hideous dovetails and cracks like this. It's not ideal, but it will work. I think after a month, you won't be concious of the repair. The piece will be preserved.

[Shawn Christ]

I would say you guys are right on, makes sense. I looked at the other side and noticed a very small crack near the post, it looks as if the rail-to-stile joint separated very slightly and may have also failed. I also noticed a slight gap where the stiles meet the posts on both sides. These joints were only face glued. This is consistent with your theory that everything shrank and the rail tenons into the posts didn't give. Any suggestions on how to avoid this in the future? Not glue the rails to the stiles if they are internal components like on this assembly? I think that is what John is suggesting.

So, lesson learned. I need to increase and monitor the humidity in the house. I think I will also take Pat's advice and leave the crack alone for now and see how much it closes in the summer.

Thanks to all of you for your helpful input. Yet another example of why I love this forum.

[Philip Rodriquez]

I'll take a different path. A stub tennon, created by a rail and stile bit, does not provide any "racking" strength. Glue one up an break it... it will look exactly like the one you pictured. A 4" wide (14 year old board) will not expand enough to break anything. I do not have my charts in front of me... but I'd bet it would be < 1/64th of an inch movement.

[David Weaver]

I see what looks like allot of shrinkage going on with the whole assembly.



It was in the pool! It was in the pool!

[Jaze Derr]

It was in the pool! It was in the pool!

You owe me a new keyboard!!! Mine now has Dr. Pepper all over it... :)

And Shawn, are you sure this isn't some kind of macho showing off here? "look guys...I broke the headboard!" nudge, nudge, wink, wink :p

[Shawn Christ]

I'll take a different path. A stub tennon, created by a rail and stile bit, does not provide any "racking" strength. Glue one up an break it... it will look exactly like the one you pictured. A 4" wide (14 year old board) will not expand enough to break anything. I do not have my charts in front of me... but I'd bet it would be < 1/64th of an inch movement.

This was my initial reaction. So what do you think is the cause?


It was in the pool! It was in the pool!

Haha! That quote never gets old.


You owe me a new keyboard!!! Mine now has Dr. Pepper all over it... :)

And Shawn, are you sure this isn't some kind of macho showing off here? "look guys...I broke the headboard!" nudge, nudge, wink, wink :p

You're on to me, Jaze. And I'm still upset the handcuff holes got yanked from the final design... ;)

[Lee Schierer]

One point not considered is the grain direction in the area of the crack. the crack followed the grain so it could have been an inherent weak area in the grain, a hidden check or "shake". It when both the vertical and the cross piece shrank the wood broke at the weakest point along the growth ring.

To repair it I would make a thin sliver of wood with similar grain and color and work it into the hole with some glue. I would not have eh end grain sticking out, but would run the grain in the same direction as the wood of the piece. Once the glue sets up, sand it smooth and refinish the area. The repair will be next to impossible for anyone but you to detect. 100 years from now it won't make any difference anyway.

[Dave Houseal]

I would watch the humidity in the basement more so than in the house. I'd definitely consider a dehumidifier...even if it is a well insulated daylight basement it will still be kinda damp.

[Shawn Christ]

I would watch the humidity in the basement more so than in the house. I'd definitely consider a dehumidifier...even if it is a well insulated daylight basement it will still be kinda damp.

We do have a dehumidifier down there but tend to keep it on a lower setting. It does not look, feel, or smell like a damp basement but I've never measured the humidity level down there. What is a good humidity level to maintain?