Looks to me that you "nailed it" with the two #10 screws, especially if they go through the holes in the conduit.
Sorry about the nail pun, couldn't resist.

 

Yep just screw it in there.

 

The screws only hold the pipe from sliding out of the hole.

In your second picture the pipe is quite a bit smaller than the holes drilled for it, so although the screws will keep the pipe fastened to the wood, they will also tend to be a pivot point, allowing the pipe to "wobble" in the hole.

To keep the pipe from wobbling, the holes need to be an almost exact fit.

 

Another option that would work for repeatable breakdowns.
Drill the holes for the conduit pipes. Drill/countersink holes up through the bottom on both sides of each conduit hole. Cut the bottom of the wood through the center of the holes. Install threaded inserts into each of the 4 drilled holes (in the top part of the wood). Install bolts up through the bottom into the threaded inserts. Install the conduits and tighten the bolts. The conduit holes will be slightly smaller due to the saw kerf and will hold the conduit.

 

One more idea for easy setup/tear down: Insert EMT couplers into the ends, with one screw removed. Replace that screw with one going through the bottom of the end (like your photo), to clamp in place. Slide your EMT into the other half of the coupler, and tighten screw- Voila!

 

You could also just epoxy the conduit into the holes if it doesn't need to be removable.

 

looks like the right side has a thumb screw holding the pipes in place. can that be done on the other side?
to help keep it from wobbling, widen the base of each end piece. you could add a 3/4" strips on both sides so there would be 2 1/4" resting on the table

 

Due to the pipe to the right side of this rack looking device it appears you want to shorten or widen the ends for each job. A slightly oversized hole, with the screw drilled through like you have been doing, or a thumbscrew to lock it down would allow that movement. If fixed, then I would use some epoxy/glue, and tighter fitting hole.

 

Not pretty,

But you could use a flange like this

Or go with threaded pipe and use one of these

 

Just buy 2 pipe clamps and epoxy the wood to the ends.

 

You might just make the sliding part thicker; that would minimize racking and wobble. If you drill the holes to just fit the conduit that will also help. Then a simple thumbscrew (brass, don't mar the tubing) in the side will keep it from moving as you work.