Lapped zipper specs

Regarding the drafting specifications for the lapped zipper, all measures are made from the center back seam line (designated as CB). CB is the zero point. You’ll add allowances from the zero point of CB.

Normally a garment has a CB seam allowance of 3/8″ and this is no exception in the area that lies beneath the zipper inset area. So excepting the length of the zipper inset, the seam allowance is 3/8″.


The length of the zipper inset area amounts to the entire length of the zipper. You don’t need to actually measure the zipper to know how long the inset area should be on the pattern because there’s an easy formula. The length of your zipper is whatever length it’s sold as which means the number of inches of zipper between the top stop and the bottom stop plus 1.5″.That’s standard. That’s broken up into 3/4″ of an inch sewing allowance at the top of the zipper -above the top zipper stop- as well as another 3/4″ at the bottom, below the bottom zipper stop.

Whether you’ve stopped to think of it or not, that 3/4″ at the top is pretty important. If you lay the pinked edge of the tape precisely aligned to the neckline of the cut edge, you’ll have just enough allowance to sew the subsequent neckline seam with a 1/4″ seam and turn it to topstitch it (with a “fold allowance” of 1/8″), and manage to not hit any teeth breaking a needle in the process. The extra 1/4″ of toothless space of the zipper that is left over, is exactly the perfectly sized space in which to sew a hook and eye. Zippers were engineered to these precise measures to allow all of these sewing operations from the get-go. I’ll bet you thought the allowance above the teeth was arbitrary. It wasn’t. Anyway, the zipper inset length is your zipper size plus 1 1/2 inches. That will most closely match the entire length of the zipper, sewing allowances and all.

Now, the only issue to resolve is the quantity of allowance needed in the zipper inset which is its total width, and according to its orientation of either left or right side. These are:
Left back shell allowance is 3/4″ from CB (zero point).
Left back neck facing allowance is 0 (zero).
Right back shell allowance is 1/2″.
Right back neck facing allowance is 1/2″

You can always print out a copy of the previously provided patterns and make these notations on them and save these as a reference. Those pieces are made to the above measures.

I’m going to give you the specs for the next zipper application, that of the centered back zipper. You can make another set of templates for that project if you like. In the centered application, the right and left sides of the pattern are exactly the same, it’s a 2-per or mirrored piece. The specs for the centered application are the same regarding the total length of the zipper inset area -that doesn’t change- but the seam allowances are 1/2″ for the back shell pieces and 0 allowance on the facings.

Hopefully I can get that up soon but circumstances are circumventing my intent. My carpal tunnel has my arm falling asleep and I’ve had an allergic reaction to the latex therapy band used to treat the carpal tunnel and all the skin on my hands is coming off in layers. And then, my refrigerator is on the fritz and I’m wondering if I can put a refrigerator on my Amazon wish list (as tho anyone would buy it anyway, lol). The alternative is a trip to The Appliance Samarai to figure out how to fix it and then, I start perseverating that my ex-husband’s bad-toaster-karma has spread to the refrigerator (we bought it together) and I’ll be doomed to appliance repair for the rest of my life.

I swear, I must have repaired the toaster four times a year when we were together and I had to be sneaky about it cause the first time I repaired an appliance (the dryer) he hired a divorce attorney. Anyway, each time the toaster was cooked, I’d tell Joe to unplug it cause it was tired and needed a rest and that in 2 or 3 days, the toaster would be good as new. He thought I was nuts but it never failed. And no, he never figured out that I was the one fixing that stuff. I eventually told him when he came to visit a couple of months ago (what is it about ex-husbands that they think divorce doesn’t include an end to the sexual part of the relationship? grrr) so I didn’t feel bad confessing to my past marital-appliance infidelities. He was pretty pissed mostly because -in retrospect- he realized he had to be utterly blind to have never figured it out before.

And I don’t even like the idea of working on the fridge one little bit because, I’m just sure there’s a capacitor in the works -I really don’t even want to think it through and then I wonder how I manage to do so much when I’m afraid of everything- and it’d just be my luck that I’d fry. I will not work on anything with a capacitor so I won’t work on tvs, monitors, or microwave ovens for that reason and I’m sure hoping I don’t have to add refrigerators to that list. Anyway, I’ll post more zipper stuff once I’ve figured out what’s wrong with my refrigerator. And hopefully there’s not a capacitor in my fridge or if there is, it’s tucked somewhere neatly out of the way. But it’d be just my luck that it is in that horrible nested gridwork of the compressor -the compressor is also scary but I guess I’ll worry/be afraid of that next. All in its own time eh?

Related:
Process review: lapped zipper
Lapped zipper template
Lapped zipper construction
Lapped zipper specs
Centered zipper template
Centered zipper construction
Invisible zipper tutorial pt.1
Invisible zipper tutorial pt.2
Shorten a separating zipper
Zippered welt pocket tutorial
Deconstructing a zippered pouch
Zippered welt pockets

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