RAS Cabinet #1: Sketchup - Torsion Box Design and Layout

Hi sIKE;

For a table that small, it is approaching overkill.

Actually, you passed overkill a while back, and I’m just being polite.

I doubt there be any deflection, even if a helicopter lands on it.

Looks good though, very nice sketch up work too.

Lee

-- by Lee A. Jesberger http://www.prowoodworkingtips.com http://www.ezee-feed.com

Lee,

I am sure there is a bit of overkill going on here, the problem is the math of course. You want mare than one or two ribs going in each direction. After that you have to find some that work mathematicaly. Trust me the math and Sketchup damn near drove me crazy.

-- //FC - Round Rock, TX - "Experience is what you get just after you need it"

sIKE, It does look like it’ll be strong.

Do you want a hand with the SketchUp end of it? You shouldn’t have needed to do any math to lay the dividers out. SketchUp will take care of that for you. Contact me if you do.

By the way, the spaces between dividers on the 25” length should all be 4 19/64”. Along the 24” side it should be 4 3/32” ;)

-- Until you spread your wings, you'll have no idea how far you can walk.

Here’s a quick little video demonstrating how I spaced the dividers in my sketch of the torsion box. I don’t have sound recording capability on this computer so it is a silent film. Description of the process follows.

Since this isn’t about making the frame, I did a simple one with the Rectangle tool, Offset and Push/Pull. The frame was made into a component so that I could draw on it without having the new geometry link to it.

I drew a rectangle to the width and length of the divider. I started the rectangle and then typed the dimensions. It is important to note where I started and ended the rectangle.

I pulled the divider to height with Push.Pull. If I was doing this for myself, I would have pushed it down which would eliminate a move step later in the process. For clarity I pulled up. Then I made it a component (not a group).

With the component selected, I got the Move tool. I invoked the copy function with Ctrl. Notice that I grabbed the component at a corner near the outside corner of the frame. I did this because I want the first copy to be aligned with the inside corner at the other end of the frame. Grabbing it where I did lets the inferencing engine snap the copy into place.

After moving the copy into place, I hit Enter followed by /5, Enter. This results in 5 copies of the original with all copies equally spaced between the first and last components.

I selected the dividers at the ends and deleted them since they are no longer needed.

The remaining divider components are selected and moved down into the frame. Notice again where I grabbed the component. Once I got the move going in the blue direction, I held Shift to lock it. Then I moved the cursor to a corner on the top edge of the frame to snap the components into place.

I hope this all makes sense.

-- Until you spread your wings, you'll have no idea how far you can walk.

So, since I’ve already hijacked your thread, I thought I’d add this little demo showing the cutting of the halving joints.

I repeated the steps above to place the crossing dividers so they are all evenly spaced. Since the dividers are components and not groups, I only need to edit one instance of each divider (long and short in this case) to edit them all. Note that after running the Push/Pull operation on the first slot, I only need double click on all of the others since the distance is the same.

-- Until you spread your wings, you'll have no idea how far you can walk.