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+-- Thread: Large Furniture grade miters? (/showthread.php?tid=7344615)
RE: Large Furniture grade miters? - Cooler - 11-29-2018
(11-29-2018, 10:15 AM)srv52761 Wrote: Ultimately , I think with 7 inch widths, mitered joints may not be the best solution.I think I agree. With a 7" width, the outer edge of the boards will be 14" longer than the inner edges. So there is 14" more wood to expand and contract on the outer edge than there is on the inner edge. The differential in movement from the outer edge compared to the inner edge is an area of concern.
A bench I made had 6" aprons and used mortises and tenons. The plan called for double tenons at each joint to mitigate the effects of expansion.
When I was a picture framer we would start to worry about miters opening in the winter months when the molding got over 3-1/2" in width. The joints would not pop the first season, but might after 3 or 4 seasons. Improved glue minimized that worry (we had "white" glue, i.e. Elmers') back then.
Even so, there is a reason tables typically have a breadboard end instead of a mitered frame.
This article is even more comprehensive and argues against a mitered frame: http://www.garymkatz.com/trimtechniques/open_miters.html
Simple, un-reinforced miter joints are the bane of carpenters everywhere, especially where humidity levels vary dramatically from winter (dry cold air—particularly with the forced-air furnace on) to summer (hot moist air…at least until the air conditioning is turned on). Understanding seasonal wood movement, and moisture content, is the key to saving your hard work from ruin. Here’s the reason why miters open and several methods for installing long-lasting, durable, interior and exterior trim.
RE: Large Furniture grade miters? - Gary G™ - 11-29-2018
In 2009, I created custom black walnut window trim for our master bedroom. Lots of other walnut trim too.
The large window is roughly 6’ tall and 8-1/2’ wide; the window trim is about 4-5” wide.
The project can be seen on LJ’s at this URL:
http://lumberjocks.com/projects/20673
There’s a close up of the miters taken at that time.
They’re as sweet and tight today as they were then.
Maybe I got lucky; maybe you will too.
RE: Large Furniture grade miters? - KyleD - 11-30-2018
(11-29-2018, 10:12 PM)Gary G™ Wrote: In 2009, I created custom black walnut window trim for our master bedroom. Lots of other walnut trim too.
The large window is roughly 6’ tall and 8-1/2’ wide; the window trim is about 4-5” wide.
The project can be seen on LJ’s at this URL:
http://lumberjocks.com/projects/20673
There’s a close up of the miters taken at that time.
They’re as sweet and tight today as they were then.
Maybe I got lucky; maybe you will too.
Yeah, my 86 year old neighbor has a Chevy Vega she actually uses to run to the grocery store once in a while. There are exceptions to everything but I know that if I wanted a wide 45 to stay tight I would use a veneer. I would not want to rely on getting lucky like my neighbor.
RE: Large Furniture grade miters? - jgourlay - 12-01-2018
Okay, so Miters are out. The bridle joint is possible, but risky -- a 7" long tuning fudge shape with enough perfection to be perfectly visible is tough. I really do not want to veneer this. This table will get used, spilled on, dinked over time and I am completely surface that veneer is not right in the application.
Aside from the bridle joint, what other method has finished look/neatness of the miter? I can of course breadboard, but that look is more of an 'arts and crafts' type look and seems like it would look funny on a square table, maybe even causing an optical illusion of not being square.
What do you think?