Woodworking Talk banner

1 - 4 of 4 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hi there! Long time listener, first time caller. I've been learning a lot simply keeping up with the forums, and I have a couple simple projects under my belt (poorly executed, but hey, learning is a process).

Currently I am tackling a long-and-thin bar top. It's about 1" x 13", and 7 feet long, with a 5.5" x 1.5" 'backboard' joined with a simple rabbet joint. I've attached a picture of the final shape below (and I even cleaned my garage first!).
428138


Now, there's a lot I did wrong on this project, and I swear I have now learned my lessons:
  • I should have used something other than a rabbet
  • I probably should put in breadboard ends
  • I messed up the grain direction on the bottom panel
  • 1" thickness was a dumb idea
but there's one question I'm having trouble answering, and it's in regard to stiffening the project lengthwise.

My original plan was to mount the bar top on a steel frame that attaches at the ends, and then stiffen the table by attaching a steel bar (or 2x3x72" tube steel) lengthwise to the underside, thus preventing bowing/sagging along the 7 foot span. However, upon completing the shape of the bar top, I realized that the backboard MIGHT provide substantial stiffening in the lengthwise direction already... and that's what I'm curious about. Will the backboard alone provide enough stiffening for the bar top to prevent lengthwise bowing/sagging?
 

·
Registered
Joined
·
644 Posts
There is nothing wrong with your design, or a rabbet joint. In fact, quite admirable for a new woodworker. If properly fastened to the top, yes the backerboard will add significant stiffness. Unsupported, over time, there is a good possibility you might see some sag over a 7' span, especially along the unsupported edge. If you are going to sit this on a steel frame I would thing that will eliminate the issues. If you feel it might be necessary, you can run a cross brace midway of the steel frame instead of the entire length.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 ·
There is nothing wrong with your design, or a rabbet joint. In fact, quite admirable for a new woodworker. If properly fastened to the top, yes the backerboard will add significant stiffness. Unsupported, over time, there is a good possibility you might see some sag over a 7' span, especially along the unsupported edge. If you are going to sit this on a steel frame I would thing that will eliminate the issues. If you feel it might be necessary, you can run a cross brace midway of the steel frame instead of the entire length.
Thank you for the support, I appreciate it! I keep seeing all of these fancy dovetails and things that are way beyond my skill level, so I've been sticking with rabbets. One day.

So unfortunately, the steel frame in question is only attached width-wise at the ends of the bar top - it does not span the length - so based on what you're saying, this is an unsupported application and I should probably not just rely on the backerboard for the stiffness. Although I'd love to be able to add a cross brace as you suggest instead, because I'm worried about cupping as well! I wonder if they make X-shaped braces...

Thanks very much!
 

·
where's my table saw?
Joined
·
28,968 Posts
That vertical piece and a rabbet joint should eliminate any tendency to sag. That's because a board will easily bend when laying flat on it's face, but stand it on edge and you can not bend it at all, it will break at about the same time it starts to bend. The rabbet joint creates more gluing area for a stronger joint. Yes, the 1" thick front edge should have an additional 1" X 2 " strip glued on to make it look thicker. I question why the vertical backstop is so tall. It will make serving over that height more difficult, but it will definitely stop the baby from rolling off.... LOL.
 
1 - 4 of 4 Posts
Top