Is a kitchen cabinet faceboard strong enough to support a bar stool?

Question

We had pivoting bar stools mounted to our kitchen counter when we built our house. I've been very nervous about anyone heavy (including me) sitting on them as they are just mounted by a metal plate with four 1/4" lag screws that just extend through the faceboard of the cabinet. I'm concerned about the thing pulling out at the top and breaking the faceboard.

The seat center is 20" from faceboard. Plate is 4x6. I believe the screws are strong enough for loads like this. However, I'm lost trying to figure if the faceboard is strong enough to keep bolts from pulling out at top.

The faceboard is some type of hardwood, not plywood, so it may be a little stronger in that respect. I'm thinking, if this isn't strong enough, maybe I can go inside of the cabinets and drill out area to access the top two bolts, replace with bolts and large washers with nuts.

The cabinet faceboard is standard 3/4". There is nothing behind 3 of the four seat mounts after the faceboard, except the one at one end of cabinet. I can't see the other at the end due to the way cabinet is made. Pictures attached. The one has another piece of wood to make the thickness of that one alone 1.5 inches. The rest of the mounts look like they use 3/4" bolts as the threads barely come through the back of the faceboard. The one in the photo that has the extra wood piece, I can add another piece for the other top bolt. Photos show that end one and what most of the others look like from inside cabinet. The circle indicates threads of one of the bolts barely breaking through back of faceboard.

Answer 1

No. The chair might rip out of the face, the face might rip off the frame, the frame might parallelogram itself to the floor. Every point of connection is not meant for this, and you're setting up leverage dead against you at every point.

Build a triangular frame from wood and fasteners that are designed for what you are doing, and in a way that will fit inside the cabinet. Attach that frame solidly to the subfloor, and through it to the joists, and attach the chair to it through the cabinet.

The diagram is supposed to look like maybe 2x4s with triangular metal brackets, but that's just a random idea. There are other ways to do it that might suit the situation better. The tricky part is designing a way that interferes minimally with the normal use of the cabinet.

Also

I noticed after drawing the above that the stool swivels. Your inner frame needs to be designed along the lines I've suggested above but in three dimensions. The structure needs to be built similarly in the plane perpendicular to my drawing.

I also see that the plan would be better if the horizontal seat posts went loosely through square holes in the cabinet, and the bracket acted on your frame alone rather than sandwiching the cabinet as in the diagram.

You are probably best off designing the structure from scratch as the foundation for both the stool and the cabinet interior, and using the cabinet manufacturer to decorate your structure rather than fit within theirs. That way you can have structural members where you need them for the stools and space in between, designed for drawers and pullouts. It's relatively easy to attach custom panels to the finished product.

Answer 2

Nothing in the cabinet's design was engineered to carry the weight of a human on a barstool anchored to it.

The design of the barstool actually acts as a lever and multiplies the force applied when someone sits on it.

I would consider the stools decorative or suitable only for very small children.

You could examine the idea of adding additional support to allow for better mounting. ( 2x4s and heavy brackets, different mounting bolts.) This would remove some usable interior space from the cabinet, but may be your only option to keep the stools usable.

What is needed and how to change the mounting would need additional info and pictures from you. You could post that in a new question.