Hanging Layout from Ceiling

Sounds similar to mine.  I planned to use rods on my long span then I decided to use Aluminum 1.5" L brackets on each side for stiffinening the span.   There are 2 3/4" plywood boards in the span, they but together in the middle of the bridge.  It is about 8 feet from wall to wall.   I have a second one 7 foot long done the same way, but it is one piece of 3/4" plywood.

I have the L brackets turned up so I don't bump them.  If you are are 8 ft high, you could put the edge down so you have a better view.   Longer span, wider L brackets.  You could paint an ironworks design on them also.   The wood bridge was also functional when I attached it, the span stiffened up some more. 

Bob - Although I think I followed your description a plan of the layout would be very helpful.  (You know a picture worth a thousand words).  What you mention probably should work?  Remember your load is the weight (gravity) so supporting that is the goal.  The threaded rods are in straight tension so the length to some degree is irrelevant. On the other hand they do absolutely nothing to resist side sway.  (You brought up the swing analogy.)  As VHubbard mentioned the bridge stiffened up his Span even though he was using 3/4" Plywood and 1.5" bracket.  Key is to build "depth" into the span.  Believe it or not, if you attach and glue the 1x4s under the 1x6 instead of on the sides it will be stiffer.  Nominal 5" deep rather than 4".

I have edited this portion of the post, if someone saw it before this edit please disregard statements made.  I realized Mr. Hubbard said the 3/4" plywood was butted together.  If not actually glued at the joint my earlier comments do not apply.

Point is, you could forget about the ceiling altogether, if you can build enough strength (think depth into the span).  Also a single hanging point at mid span gives by far "the biggest bang for the buck".

Hope this helps, BTW I am a retired Mechanical Design Engineer that designed Heavy Industrial Machinery.

Here are a couple of sketches of my idea for a hanging layout.  As stated before, I'm not to crazy about using threaded rods.

@SantaFeBob posted:

Here are a couple of sketches of my idea for a hanging layout.  As stated before, I'm not to crazy about using threaded rods.

Being a retired Design Engineer I am very conservative in my design approach.  What you are planning is well thought out and way more than adequate.

Without using the ceiling, to support the ends of the 2x4s you could run a diagonal brace underneath back to the wall.  On the end where the doors I realize of you are limited to being above the door "trim" so about 7 feet off floor.  This only gives 1 foot of depth at that end.  On the other wall would run down as far as you would feel comfortable, don't want to make a "head banger".  Not sure if you would like the look of the brace.

A better way might be to basically keep what you were planning.  Rather than using threaded rods use steel or stainless steel cable, you can decide how to attach, and run it back to the wall just below where it meets the ceiling. Believe this is about 4 feet above the layout, so would give you about a 45 degree angle, depending how far out you attach.  Not sure how much you have worked with cable but they make end attachments that are adjustable so you can get the proper tension.  Search the internet.  Cable is "crazy strong".  Use 1/16 or 3/32 diameter.  If you went with your original plan to run to ceiling you would hardly be able to see 1/16 cable.  With the diagonal method I would use 3/32 just because I am so cautious.  BTW when cutting cable get it pre-cut or use the proper tool.  Otherwise you will "fray" the ends.

Hope this helps, good luck with whatever you decide.

Bob,  A Cable Stayed Bridge might look good up there.

This one is 6' across and 10" deep to hold two tracks.

The orange bridge is 7-1/2' across and 8' deep for a single track.

Doug