Estes MRN Orbital Transport Laboratory Build, Part 10, Dowel Hole Positioning

Holes were punched and enlarged slightly for a tight fit of the dowels.

TIP: You can clean up the burr left from the punch with a sharpened dowel. Rotate the tip in the hole to dress the edges.




Here's how the fins ended up -
You can see how the "fin holder" tip overhangs the inside edge of the main tube.
The corner tips will be glued onto the lowest 20/60 engine mount centering ring.

Notice the hole drilled in the 20/50 ring for the fin dowel to be glued into. The picture on the left is the "after" shot to show what you are going for.

Lines are drawn down the motor mount tube to help line everything up when the mount is slid into the glue ring.
I used the rat tail file to line everything up then the pencil lines were drawn.

Pressing and turning the file tip made small divots (pilot holes) in the centering ring.
A 1/8" drill was spun by hand into the centering rings but not into the BT-20 motor mount tube.