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?

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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  1. kathleen says:

    lines, timers and hairs, oh my.
    I think the fridge has a problem with the defrost timer but to start, I’ll open the back of the freezer (from the inside) to clean all the cat hair off the evaporator coils ’cause I don’t need to see it, I know hairs there.

    btw, the greatest secret to fixing _anything_ is to unplug it, open it up, clean it out and reconnect orphan connectors and wires. honest. no brains req’d ;)

  2. Tom Willmon says:

    My reefer died a few months ago and I replaced it with a good, used reefer/freezer from a local peddler for $75 delivered.

    You may not like current new prices…

    Good luck with troubleshooting and repairing as first line of defense. I agree with suspecting defrost timer.

    (recovering engineer)

  3. kathleen says:

    I can’t figure it out; the freezer (top) is barely keeping ice cubes solid and the lower portion is too warm to keep milk cold (but the butter is solid) so it should be a defrost timer issue. The thing is, the freezer compartment is NOT iced over, so it can’t be. It has me confused so I’m starting to wonder whether this unit (Kenmore Coldpoint, manuf date of 09/99) would have a timer on the heater. Or do all of them have a timer on the heater but I just haven’t figured it out yet?

  4. kathleen says:

    It turns out, the fan cooling the compressor was on the fritz and only running intermittedly which is why I didn’t know what the problem was at the outset (read: the latter is my “excuse”, lol). The fan was 67 bucks -wholesale! good grief! I couldn’t believe it; for a little motor, 3″ fan blades and scraps of cut -and unburnished- sheet metal for the mounting frame, it cost that much. Well, it’s running great now and I didn’t lose much in the way of spoiled foods. It was one of those times that I was glad to be a vegetarian ;).

  5. Eric says:

    Once upon a time we had a fridge that wouldn’t keep things frozen or very cold, and it turned out that the coils were just so dusty/dirty they couldn’t conduct heat/cold properly, and a good thorough cleaning with a brush got it back to good as new.

  6. kathleen says:

    I’d already pulled this thing back from the wall a couple of months ago to clean it out because of the change in the noise of it. While it sounded a little better, it still sounded off so I’d been expecting for something to happen with the thing at any time. I like that about machines. Unlike people, they’ll usually give you a heads-up when they’re not happy.

  7. Q:
    I’m assuming your seam allowances require some standard zipper tape width. In my own attempts to figure out how to sew a zipper in well (I opened up a thrift store garment that looked particularly good), I did figure out that the seam allowances of a centered zip had to be exactly 1/2 the width of the zipper plus a bit ( ~1/16″ usually works for me) to go over the coils. So I started measuring zippers and did NOT find them to be standard. They seem to range from 3/8″ to 3/4.” what gives?

    I never did figure out lapped zipper (honestly, the off-centeredness of the topstitcng bugs my eye.)

    Sort of on this topic. As a beginning sewing instructor, I’ve figured out why the home sewing method is the way it is: Beginning sewers can’t sew straight, sew dot-to-dot, keep layers perfectly aligned, or prevent the fabric from getting eased to the zipper (especially without interfacing. Note that most interfacing available to the home market SUCKS. If I were writing home-sewing patterns, I would avoid it, too). Sew, the home-sewing method at least up the chances that the zipper gets in sorta correctly.

    And I would have included myself in the beginner sewer category for my first 10 years sewing (I’m on year 12 now. Currently, I’m intermediate.). How are you going to get people in sewing classes if you tell them they’ll suck for another 8 years??

    On refrigerators–I have heard that new fridges are more energy efficient, and pay you back in electricity bills pretty quick. My (2 person) household only has a minifridge. everyone said we were nuts and that we’d miss the fridge space, but we don’t,
    hah! Minifridges are very cheap. Of course we are very blessed with an abundance of farmer’s markets, plus Berkeley Bowl (if anyone ever visits me in Oakland, I’ll take you. It’s a grocery store, but it might as well be an entertainment venue!).

  8. Sara says:

    For a fully lined dress with a lapped zipper, would I use the same seam allowances for the lining patterns as for the facings, i.e. left back lining as 0 and the right back lining as 1/2″? I can’t quite figure out in my head how to draft the left back lining.. Would it step from zero to 3/8″ at the end of the zip?

  9. Kathleen says:

    For a fully lined dress with a lapped zipper, would I use the same seam allowances for the lining patterns as for the facings, i.e. left back lining as 0 and the right back lining as 1/2″? I can’t quite figure out in my head how to draft the left back lining.. Would it step from zero to 3/8″ at the end of the zip?

    Yep, and you’d end up with a jog (forming a square opening) at the zipper end. Make sure you leave the box end long enough to finish it off (flip it up). Do a sample and you’ll see what I mean.

  10. Anne says:

    Thanks so much for the tutorial on the lapped zipper application. I did add a lining and had 0 zero seam allowance on the left side until the bottom of the zipper stop. Then became 3/8 inch. I think I wack the zipper a tad too much ..metal was smashed!! But the whole sample came out very nice….I would appreciate your feedback on some issues I came across. These are some of my questions.
    1) When top-stitching the facings away from body do you topstitch all the way done the lining?
    2) Not sure what to do with the small 3 side square that formed at bottom of zipper? This was on the lining.
    3)At the end how much should you topstitch the zipper on the left side of the shell, the right side seems to be easier to do?

  11. Tina Spear says:

    Kathleen, so would the lapped zipper construction be the same for a bodice which is lined rather than faced? And, would the dimensions of the lining be different than the dimensions of the bodice? Right now, the pattern is the same for the lining and the bodice.

  12. Tina Spear says:

    Oops, I just saw Sarah’s question and your answer after I posted mine. I will follow your reply to Sarah & give it a try. Thanks for your blog.

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