Empennage: Elevators. Rolled leading edges.

After much reading of various RV blogs and VAF, I decided on the following method, as described in this VAF post.  Another example of a similar process is found here.  Getting this right is important, otherwise it could lead to cracking.

I obtained some 3/4" ID conduit which was 15/16" OD.  I drilled similarly sized holes in three blocks of wood, leaving the holes much closer to one end than the other (to accommodate the elevator spar) for the conduit to slip in, then cut one side of the blocks just tangent to the holes.  This netted me three of the following.

I then laid a sliced-open trash bag on the work table so the elevator could slide along the table with lower friction.  The picture below also shows the conduit slid into the clamped-down wood blocks.

Next I applied duct tape (does anyone actually use that stuff on...ducts?) to one side of the elevator skin.  Half of the width of the tape was stuck to the skin, leaving the other half for the conduit.

I slid the conduit into the three blocks.  Then I placed the elevator on the bench with the flayed trash bag and nested the conduit against the spar temporarily to ensure the blocks could fit in the two spaces for the horizontal stab hinges and the other block could fit adjacent to the inboard skin edge.  I then wrapped the remaining width of tape around the conduit.

Then I inserted a pipe wrench fitting into the conduit (which held up for two rolling events, after which I just used a channel lock) and twisted the assembly.  The elevator was drawn in as the skin was rolled.

What I ended up with was the image below.  The roll was not close enough to the spar so the skins were nowhere near close to each other.  Had I continued rolling, the middle edges would have been curled inwards too far.  So this caused me to do a lot of manual bending, trying to avoid creasing the skins at the spar.  On the other elevator, I tried placing the conduit further in towards the spar prior to taping things down, but the outcome was the same.  If I were to do this again, I'd use a 1.5" OD pipe.

Eventually I coaxed the skins to get their holes to line up, but with more "preloading" then I prefer.  An apt characterization of this process might be "less than fun".

And although the top skins overlap the bottom skins without gaps (due to both the "edge break" I imposed on the tops skins and the fact that the top skins curl inwards), the bottom skins don't quite sit flush against the top skins (because the bottom skins also curl inwards).  See below for illustration of that outcome.

Currently the elevators sit with their leading edge skins cleco'd up.  I'm debating on what further to do, if anything, before riveting.  That pre-loading to get the skins to align isn't appealing.