JIG BLOCKS: These things are/were a god send during the fuselage, lower wing assembly and are still used around the shop. They helped during the fuselage layout and keeping things square when the sides were joined. They functioned to raise the tubing off the table and allow the gussets to wrap around during riveting. One neat aspect is noting the guide line as shown(ABC on the drawing). These lines allow you to locate the blocks during layout. The lines positions the block for the two tubing sizes and, if you look at the
plans, some tube locations are "centered" and some locations are off set.Line A is for edge alignment regardless of tube size. Line B is 1/4" from line A and equals the center of the 1/2" tube, and likewise ine C is 1/2" from the edge line and centers a 1" tube. Position the block with the two "ears" on the bottom and screw (drywall) it down, the tubing lays in the top cut out and is held in place with the little rectangular piece (D). This
rectangle was "off fall" from making the notch and is screwed in place as needed. We off set the screw hole a little so the rectangle could hold a variety of sizes with out re-drilling the screw hole ( that sounds better than what really happened...I miss
drilled, but it worked better!). Note...get the best grade of 2x4 to make these, ..not the $1.89 wonders at Builder/Menards. GO TO A LUMBER YARD! Get two PREMIUM STUD grade ZERO defect 2x4! NO TWIST, WARP OR BOW. You'll be glad you did.
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