Bowed top on Chest of Drawers

[michael dilday]

I am building a chest of drawers out of soft maple. It is 40" wide and 18" deep. Getting ready to put the drawer fronts on and noticed that the top is bowed down slightly - probably 3/16 in the middle. I am not real excited about trying to cut that arc in the top drawer front. I was thinking about putting a straight edge on the top and clamping it straight. Then taking a piece of 3/4oak the entire width and depth and gluing it inside of the top with the grain running long ways. Hopefully the increased thickness of the top from the 3/4 soft maple to the 1 1/2" combined will stiffen it enough to keep it straight. I tried clamping the 3/4 oak on both ends to see if the oak would overcome the maple but it didn't. May have pushed it up a little but looked like the oak mostly followed the arc of the maple. Any ideas?

[Mel Fulks]

First thing to try is just turn it convex side up on a flat surface. That might let it loose some moisture and flatten.
sometimes that works

[michael dilday]

First thing to try is just turn it convex side up on a flat surface. That might let it loose some moisture and flatten.
sometimes that works

That is a great idea Mel. I should have thought about it. I did something similar I put a 2x4 on the top with a couple of spacers on each end and bowed it about 1/8" opposite the natural bow. Hopefully in the morning it will be close to neutrally straight and I can put the board underneath and glue it to it. I was going to put a piece of maple under the top as a drawer stop with hardboard over the drawer to keep the clothes from jamming up. I put drawer separators/dividers on all the other drawers with hardboard to keep the clothes from jamming. It is a mid-century modern design with drawers inset 1/4" from the front of the cabinet. No face frame. Thanks for your reply Mel.

[Jamie Buxton]

If a straight reinforcement doesn't make the top flat, make the reinforcing piece curved. You get different amounts of upward force depending on how curved you make the piece.

You can even do some adjustment. Make the curved board stronger than you really need. Glue it in place. The top-plus-reinforcer will hump up. With a plane, spokeshave, or a belt sander, remove a little of the bottom face of the curved board. The top-plus-reinforcer will straighten down a bit. If it is still humped up, remove some more. Adjust until the top is flat.

[Richard Coers]

There is a reason the maple moved out of flat, you should probably try to figure that out before you try to wrestle it into submission. One solution would be to cut a couple of kerfs under the top and relieve the stresses. Was it ever really flat? Did you joint and surface the wood flat before gluing it up? Is the wood kiln dried?

[michael dilday]

There is a reason the maple moved out of flat, you should probably try to figure that out before you try to wrestle it into submission. One solution would be to cut a couple of kerfs under the top and relieve the stresses. Was it ever really flat? Did you joint and surface the wood flat before gluing it up? Is the wood kiln dried?

I jointed and planed it and I am certain it was flat (I think). I checked the top ends of the sides as best I could with a square and those cuts look square. They should be my table saw is dialed in. I also took accurate inside measurements of the sides and they are exactly 38 1/2" at the very top and in several measurements so they aren't bowed out - thought that could be causing the top to bow down. I even took the top drawer separator / divider out and put a clamp on the sides to pull them in slightly to see if they were putting stress on the top and I don't think that is the case. It has only been assembled for a week or so - not sure if it could have simply warped in that time with no other weight on top. I currently have it bowed up with a couple of clamps and a board. I guess I will reinforce it with a 1/2-3/4 board underneath and take what I get. Then make the drawer front to fit the top.

[michael dilday]

I think I figured out the cause. When I installed the top I used 50” Beasley Parallel clamps to hold the top in place while I picked screwed it in place. The clamps are 3.5” so they extended over the unsupported top 2.75”. I think the pressure of the clamp was enough to make the joint slightly out of square. Reversing the sag upwards is moving it to square quickly. Thanks for your help.