Question about bullnose and expansion
Friends:
I am building a pair of built-in White Oak counter tops. They will be roughly 24″ wide, plus a ~2″ bullnose, also of White Oak. The challenge is that the bullnose must wrap around on three ends out of four for the pair. I am assuming that, like a breadboard end, it must not be glued to the end grain of the rest of the surface. However, the mitered corners must hold tightly and not open as that would be very unsightly.
For a variety of reasons, I can’t use mortises and tenons, and lack a biscuit joiner. Also, as mentioned, the preferred –specified — look is mitered.
Remember that as a counter, the back side will be attached firmly, so all the expansion from the 24″ span will go in one direction; that is, forward.
Current thinking is to pin and glue the mitered corners, and glue to the first few inches of end grain. The rest of the wrapped bullnose would be fastened to the substrate in such a way as to allow it to slide forward and back, but not sideways (using stainless screws and washers with the screws riding in slots in the substrate).
So what is the thinking? Is this likely to work? Will the varnish finish glue the wood together and ruin my plan? Is there a better way?
Cheers!
Joe
Replies
Joe
Have you thought about using 2" thick stock for the entire countertop, and cutting the bullnose directly, without adding a "moulding". Otherwise, I think you're asking for a failure.
Walnutz
Joe,
I'm a bit unclear about the construction you have in mind. Your mention of substrate leads me to believe that it's not a solid countertop...?
I'd certainly prefer to make the whole thing of 2" thick material, and run the bullnose profile right around as needed, not as a separate piece.
regards,
David Ring
http://www.touchwood.co.il/?id=1&lang=e
Good points about the solid counter, but it is not an option here. We are replacing an old counter and have space constraints that require is to use 3/4 stock -- and also, that part is already made. It will be attached to a 1/2 inch plywood substrate using stainless screws and washers fitted through 1/2 inch long slots in the substrate, thereby giving room for expansion. The existing (and soon to be replaced one) has a bullnose that comes out and overhangs.
If necessary, we could do away with the wrap around bullnose and come up with another design feature that would let the counter slide, such as, perhaps, upright ends with 3/4 dadoes. The uprights could be permanently fastened, leaving only the bullnose on the front. That would have the mechanics of a breadboard end more or less, wouldn't it?
Joe
Joe,If you've got about 2" of overhang for the countertop, here's a neat way to "fake" the thickness of any board all around the perimeter.See my rough sketch attached.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
That's a great solution! I hope I can remember it if/when I run into that problem.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
May I ask a wonderfully dumb question? I'm embarrased to ask, but....
What do you guide the bullnose bit against when you apply the bullnose to the countertop edge with the router? I KNOW that this is a dumb question, but I can't for the life of me figure this out.
Mike D
The ones I am using have bearings on the bottom that run against the flat of the wood. Only the part over the bearing can be cut, and the bearing limits the depth of the cut.Joe
Use a 5/8" rad bit with a nose bearing. You don't get a true bullnose but its very close with alittle sanding blends right in. Only other way is to use a portable fence attached to the router base, just a real trick to setup right.
I can see that some sort of guide is a necessity. I purchased a lovely bull nose bit, somehow imagining that I'd put same into my router and sort of "swoosh" it over the edge, forming a perfect bullnose.
Naturally, as in all my woodworking learning, things are not as simple as imagining makes the.
I am making my first piece of serious furniture, and I discover that I am OFTEN finding my self wondering "Geez, just how am I going to do THAT?" AND, naturally, each of these little opportunities for self improvement come at a point where, if I get it wrong, will result in the butchering of some very pretty and expensive wood, that has a wee number of hours into it, as well.
Mike D
I've done similar things on breadboard ends -- tieing the breadboard end firmly at one end instead of the middle. It works, and your plan should work too. The one thing I don't understand is how you're going to keep that sliding joint from opening. I've used the classic breadboard approach of a pinned sliding mortise and tenon. That is, there's a tenon on the ends of the main surface and a mortise in the breadboard end. There's a pin or several which runs through the breadboard end and the tenon. The holes through the tenon are elogated to allow the tenon to slide sideways. However, the pins keep the joint from opening. You can insert the pins from the top to make them visible, or from the bottom to keep them invisible.
Thanks, Jamie and David. Am revising thnking rapidly with your input. WIll try to post sketches later today if I can figure out how to do it.
Joe
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