How to Machine Piece Hexagons
When joining hexagons rows by machine, set-in seams are required. Though the positioning of the pieces is unusual, sewing hexagons together by machine doesn't have to be difficult; just take it one seam at a time, pinning and sewing carefully.
Practice this technique with the pattern Making the Cut by designer Diane Reinhart, shown on this slide.
To join hexagons in vertical rows, adjacent rows need to be offset. (Example that follows shows top hexagon in Row 2 already trimmed to make a half hexagon.)
With right sides together, place first Row 2 hexagon atop first Row 1 hexagon. (In this example, Row 2 begins with a half hexagon.)
Note: Many patterns have you draw dots 1/4" from each hexagon point using a template for your seam allowance. If your pattern doesn't do this, make sure you start and stop sewing 1/4" from each point.
Push a pin through each pair of dots to align pieces, then pin pieces together.
Sew from dot to dot, locking seam ends with backstitches or tiny (0.5-millimeter-long) machine stitches.
Open up pieces and reposition Row 2 over Row 1. Align and pin next seam.
Without catching seam allowance in stitching, sew next seam from dot to dot.
Open up pieces and reposition Row 2 over Row 1. Align and pin third seam.
Sew third seam from dot to dot. Do not sew through seam allowances. Continue in same manner until all seams are sewn.
Press first seam intersection counterclockwise, forming a tiny hexagon on the fabric wrong side. Press next seam intersection clockwise. Continue alternating the direction you press as you continue down the row.