Things like this makes me wish engineers had to build their own design. 3.75" of elastic 1/4 in seam allowance, then have to bartack 2 places 1/2 in on the seam allowance. Tolerance 1/16 of an inch. On a bartacker, the needle stays still and the foot moves the fabric in a zig-zag motion. Out of the 6, I’ve made, I’m only willing to pass one on to quality. I was given 1 yard of material to do this so I get 11 tries to make 3 and the bartack damages the elastic, no do overs. Did I mention despite making first articles, the items which get us the contracts, we’re last on the equipment list. This machine is almost 30 years old.Bartacking elastic video
Update: another spot has 2 -1/8" bartacks in 1/2" there’s a 1/4 " between the bartacks and 1/8" beyond the last bartack on this end. With a 1/16" tolerance. The 2 bartacks and the space between add up to 1/2" so I have to cut my piece longer, stitch it just right and then cut the excess down to 1/16" so I’m at the low end of tolerance on the 1/8" measure and high end on the 1/2" measure.
engineers should understand tolerance
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Well my tolerance is 1/32 on an 1/8 so I’m going to have to shrink my bartacks 1/32 to make my 1/8 on the end of the 1/2. This is a constant struggle military and civilian. They love to draw lines as bartacks and not check their math. It would be more cost effective to update the drawing the time lost in production is huge. This drawing for instance was made in 1958 and we’re on REV N, but the government doesn’t like feedback from contractors. On the other hand I have a civilian company, 2 pages of drawing issues and they updated most of it.
yeah… what they are gonna say is … somehow it worked for over 50 years 
same thing in Aircraft. We make rivets as symbols and that also causes troubles. (and back in the old days people had to imagine the 3D… so there are some awful drawings out there that just got fixed in manufacturing.)
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