L shaped bar joinery

[Matt Roth]

I'm building a bar top for a L-shaped bar. I'm pretty sure I will miter the joint and have the 2 sections meet at a 45. Any suggestions on the best way to join the two sections with the goal of sealing the gap from spills and allowing for seasonal movement? I was planning on finishing all sides with several coats of waterlox, and mating the two with a bead of silicon caulk. Both sides would be anchored from bottom, through 3/4" plywood base cabinet with oversize holes in ply and fender washers. Any better ideas? Thanks!

[Jamie Buxton]

What material are you thinking for the top -- plywood, or solid lumber?

Do you have to join the two arms in-place, or is the L small enough that you can join them in the shop?

[Tom Norton]

What about a spline in the mitre?

[Matt Roth]

Material is 1" brazillian cherry. It could be assembled in the shop and carried to the bar.

[Prashun Patel]

Do you mean the TOP will be two flat panels joined at 45 degrees, so that the grain will be going perpendicular to each other? Man, I have a tough enough time getting mitered boxes to stay together through seasonal movement. I would consider doing a veneered top over a substrate that won't have the wood oriented at cross purposes. I've never done this, though, so I'm just giving food for thought.

[Matt Roth]

Do you mean the TOP will be two flat panels joined at 45 degrees, so that the grain will be going perpendicular to each other? Man, I have a tough enough time getting mitered boxes to stay together through seasonal movement. I would consider doing a veneered top over a substrate that won't have the wood oriented at cross purposes. I've never done this, though, so I'm just giving food for thought.

That's exactly what I'm talking about. I'll put a pic up tonight. It's going to be solid, veneer isn't an option.

[Bob Lang]

The standard approach to joining tops like this is to run a spline along the joint to keep the top surfaces even, and pull the joint together with special bolts from below. You need to rout recesses for the bolts, but they pull the joint together. Fast Caps makes a good one called the "Flip-Bolt".

http://www.fastcap.com/estore/pc/Fli...nector-8p8.htm

[Jamie Buxton]

That's exactly what I'm talking about. I'll put a pic up tonight. It's going to be solid, veneer isn't an option.

It is a bit difficult to visualize, but the cross-grain expansion and contraction of solid lumber acts to change the angle at which the two mitered arms meet. Plan accordingly.

[Sam Murdoch]

The standard approach to joining tops like this is to run a spline along the joint to keep the top surfaces even, and pull the joint together with special bolts from below. You need to rout recesses for the bolts, but they pull the joint together. Fast Caps makes a good one called the "Flip-Bolt".

http://www.fastcap.com/estore/pc/Fli...nector-8p8.htm

+1 to Bob's suggestion. Here is a video of a counter top bolt without the "flip" mechanism - http://www.youtube.com/watch?v=K3uRFzbv8KM

As an option to the spline you can use Dominos for the alignment. I would not use use silicone between the joint but rather thin epoxy. Finish the top after making the miter (my preference) or tape off the miter edges before finishing - keep the Waterlox out of the joint. The top will expand and contract as a unit if properly attached to the substrate to allow movement of both sections.

[Kevin Jenness]

Allow for movement. As stated above, a mitered solid wood assembly's angle will change with relative humidity changes, or if the angle is forced to remain constant, the miter joint will open. Attachment to the structure below must allow for the anticipated movement. You might want to consider a 90 degree butt joint reenforced with splines, tenons or inserted tenons to keep the surfaces aligned, glued only near the outside corner, and pulled together with "zipbolts". A "microbevel", or slight easing of the mating edges, will help to disguise the misalignments that will occur with seasonal movement in an unglued joint. If your lumber is not acclimated to the anticipated humidity levels it will encounter after installation, the movement can be considerable. I am not experienced with jatoba (Brazilian cherry), so I would research its potential movement re humidity before deciding on the joinery. A useful tool is the timber movement calculator ("shrinkulator") at woodweb.com.

[Matt Roth]

Bar Counter Removed.jpgBar Finished Total Area.jpg

Here's a couple pics of project. Thanks for the feedback so far!

[Sam Murdoch]

Based on my experience building such tops I do not hesitate to reiterate that a well mitered/glued joint as is I described in my post # 9 above will not open if the top is installed properly. Allow both sections to move - that is to float on top of a sub top and the joint will follow. I add one qualifier - when I have done this I have used the same boards in the same sequence running the full lengths from one section to the next and I did not lock the perimeter in with some type of applied molding. I have not had issues with the miter joints breaking.

Here is a bad photo to at least show that I have built such a top (this one about 4 years ago) though I do not have view from above available. This was a solid walnut top with 2 mitered sections attached to float over a plywood substrate. The center boards were 3/4"+ thick x approx. 3 1/2" wide but the perimeter boards were 1-1/4" x approx. 3 1/2" wide. The one end that was open I filled in from under to maintain the thickness of the finished edge but the filler board was severely cut back so that only the very outside edge was touching the cross grain of the two sides.

P3181317.jpg

[Kevin Jenness]

Sam, I agree that the miter will stay tight if installed as you suggest. It is a fact, though, that the miter angle will change as the moisture content cycles throughout the year. Given that Matt's project has a scribed end where it meets the wall, he should probably fix that end to keep the scribe consistent and let the other leg pivot from the miter.The overhang and angle of the top to its base will vary somewhat throughout the year, probably not significant given the design. I would try to calculate the variation based on the species, grain orientation, initial moisture content and range of MC in service, and overall dimensions in order to ensure that the fastening holes are large enough to accommodate the expected movement.

If using a miter I would definitely glue the joints with splines, Dominos or similar. The butt joint I suggested would be more appropriate for a situation with small overhangs where the angular variation arising from a miter might be objectionable.

[Matt Roth]

It's been a while since I started this project, but I wanted to provide an update. I wound up using dog bone bolts, large biscuits, and glueing the entire length of the miter. I was surprised at how difficult a cut this turned out to be. It was too big to put though the table saw, using a router or circular saw proved to be close, but not precise enough. A new tool to the collection worked perfect, a makita track saw. Anyway, I left the long end floating, so if the angle wants to drift season to season, it's free to do so. Thanks for all the help. I'll post updates if something fails once summer sets in. The end of this project is in sight!

[Matt Roth]

I stumbled across my old thread and thought I'd provide a 5 year update. The joint is as tight today as the day it was glued. Awesome help with this project above. Thank you all!