Custom Auto Lock Boxes
The base of a folding carton is normally four flaps and about eight seconds of somebody's time. An auto lock bottom removes both. The box arrives flat, you press the two ends together, and it stands up square with the bottom already made.
- Build
- Auto lock bottom with a tuck or seal-end top
- Board
- 16–24pt folding boxboard, kraft or white-lined
- Assembly
- Ships flat; squares up in one movement with the base locked
Get a price for Auto Lock Boxes
Send the size and quantity — we reply the same working day with a price, a dieline and a date. Artwork optional at this stage.
- Free dielineThe flat drawing comes with the quote, before you commit.
- Proof before pressNothing is printed until you have seen it laid on the dieline.
- Die kept for reordersTooling is paid once. Every reorder skips straight to press.
- Quoted in four marketsUS, UK, Canada and Australia, in the delivery currency.
What the mechanism actually is
The base flaps are pre-folded and pre-glued to each other in a pattern that collapses flat and unfolds under its own geometry. Squeezing the box into a square pulls the glued flaps into an interlocking floor with no free edges.
Because the joint is glued rather than tucked, the base carries load through the glue line instead of through friction. That is why it holds weight that a plain tuck bottom will eventually let go of.
It only works if the box is squared properly. A carton assembled half-open has a base that is not fully locked and will fail under load.
The maths that decides whether it pays
The per-box premium comes from the extra board in the base and the gluing pass. The saving is measured in seconds per unit, so it scales with volume and with how much you value the person doing the folding.
| Under 250 units | Hand-folding a tuck base is cheaper; the glue does not pay back |
|---|---|
| 250–1,000 | Marginal, and it depends on who is packing |
| 1,000+ | The labour saving is real and compounding |
| Any fragile or heavy fill | Worth it at any quantity, for the base strength alone |
Where it beats a snap-lock
A snap-lock, or 1-2-3 bottom, is also strong and costs less because there is no glue. The difference is entirely assembly: a snap-lock has to be folded and tucked in sequence by hand, every single time.
For a business packing a handful of orders a day, a snap-lock is the sensible build. For a line, an auto bottom pays for itself within weeks. The full comparison of base builds is in our tuck end carton notes.
What it does not fix
- The top still has to be closed — usually a tuck flap, sometimes a glued seal end.
- Grain direction still decides whether dark solids crack along the folds.
- Board weight still has to match the filled load; the base being glued does not make the walls stronger.
- It ships flat but not as flat as a plain tuck blank, because of the pre-folded base.
Designing artwork around the base
The base panel of an auto bottom is a complicated shape made of overlapping glued flaps, and artwork across it will not line up. Anything you print there is for the machine, not for the customer.
Keep the base blank or use it for batch and handling marks. Put the design on the four walls and the top flap, where the geometry is simple and the print lands where you intended.
Auto Lock Boxes — specification
The rows that are specific to this build first, then what applies to every job we run. Anything not listed is a question, not a limit — send the brief.
This build
- Build
- Auto lock bottom with a tuck or seal-end top
- Board
- 16–24pt folding boxboard, kraft or white-lined
- Assembly
- Ships flat; squares up in one movement with the base locked
- Load
- Glued base carries substantially more than a tuck bottom
- Four walls and the top flap; base panel left for handling marks
- Minimum
- 100 cartons
On every job
- Print process
- Digital below about a thousand, offset above it. One side or both, with spot colors where a match has to hold.
- Color
- CMYK as standard. Uncoated and kraft stocks print lighter and warmer; a spot color is the only exact match.
- Tolerance
- Cutting plus or minus 1 mm, creasing plus or minus 0.5 mm, confirmed on a plain sample before the run.
- Tooling
- A cutting die per size, made once and kept. Foil and emboss dies per artwork, also kept.
- Food contact
- Food-grade board and inks where the carton touches food, with the interior left plain.
- Sustainability
- Mono-material board wherever the product allows; recycled-content and FSC stocks; no claim printed the pack does not earn.
- Artwork
- Vector PDF or AI, 3 mm bleed, 4 mm safe area, fonts outlined. We check every file and send a proof before press.
- Dieline
- Supplied free with the quote, before you commit. Yours whether or not you order.
- Sample
- A plain unprinted sample at the finished size on request, for fit and construction.
- Reorders
- Skip the tooling and go straight to press at a lower unit price.
- Lead time
- Quoted with the price against your fill date rather than promised before we have seen the spec.
- Markets
- United States, United Kingdom, Canada, Australia — priced in the delivery currency, freight included.
Boards and films we build auto lock boxes on
A folding carton is one sheet of board, so the board is the product. These are the stocks we run for cartons, what each is good at, and where it lets you down.
Natural kraft
Unbleached folding board. Warm, hides marks, costs least. Mutes color — one or two flat colors print well, photographs do not.
250–350gsm sleeves; 14–24pt cartonsWhite SBS
Solid bleached sulfate: bright, coated, the retail carton standard. Takes accurate color and every finish. Shows scuffs sooner than kraft.
14–24ptWhite lined chipboard
A recycled gray core under a white printing face. Cheaper than SBS and slightly duller; the back of the sheet stays gray.
16–24ptKraft-look coated
A kraft face over a coated inner. The natural look with a barrier behind it — the answer where oil, grease or moisture would mark plain kraft.
14–20ptRecycled-content board
Post-consumer fiber with a gray-brown cast. Right for outers and inner components; poor for bright whites and photography.
16–22ptMicro-flute E and F
A fine corrugated layer where a carton needs structure it cannot get from board — a large panel, a heavy product, a box that ships alone.
E 1.5 mm; F 0.8 mmUncoated and textured
No clay coat, or a linen or laid grain. Print reads softer and warmer; a deboss goes deeper. Photographs do not sit well on it.
280–350gsmMetallised and pearlescent
A metallic or pearl face for a shelf that needs to catch light. Costly, and it fights a photograph — a mark or a pattern suits it better.
16–20ptNot sure which? Say what goes in it and where it is sold — the material follows from that. Our notes on recycled, recyclable and compostable cover which claims each stock can honestly carry.
- 01
Send what you have
A dimension, a photograph beside a ruler, or the product itself. No technical drawing needed — that part is ours.
- 02
We quote and draw
A price, a dieline and a date come back together. If a different build would suit the product better, that is in the reply too.
- 03
Approve the dieline
The flat drawing is yours to check: which panel is the front, where the folds fall, how deep the cavity really is.
- 04
Artwork on the dieline
You place your design on the flat we sent, or we place it for you, and you see a proof before anything goes to press.
- 05
A sample if you want one
A plain unprinted sample at the finished size shows fit and construction — the things a drawing cannot.
- 06
Cut, printed, shipped
The die is cut once and kept, so every reorder skips the tooling and goes straight to press at a lower unit price.
Format
Vector PDF or AI where possible. Raster artwork at 300dpi at final size, in CMYK.
Bleed
3 mm past every trim line, so a fraction of drift on the cutter never leaves a white edge.
Safe area
Keep type and anything important 4 mm inside the cut and away from every fold.
Color
Convert to CMYK before sending. Uncoated stock prints lighter; a spot color is the only exact match.
Fonts
Outline them or supply the files. A missing font substitutes silently and the proof will not match.
Barcodes
On a light, matte, unvarnished patch with the quiet zone clear — a code on gloss fails the scanner.
Not set up that way? Send it anyway — fixing a file is a short conversation, and we check every one before press. Our guide to preparing print files covers each point.
Every finish here is a decision about light on a shelf, not about luxury.
Matte lamination
Reads considered, hides marks, takes a ballpoint.
Gloss lamination
Lifts color; glares under shop lighting.
Soft-touch
Velvet in the hand; shows fingerprints in a bag.
Hot foil
Real metal leaf — the most reliable premium signal.
Emboss / deboss
Shape with no ink; works in the dark.
Spot UV
Gloss shapes on a matte field.
Uncoated kraft
Warm, natural, mutes color.
Textured stock
Texture in the paper; cannot scuff off.
Not sure which suits the shelf it sells from? Say where the product is sold and we suggest one — our notes on specialty finishes show them on real boxes.
Sizing a folding carton so the die comes out right: auto lock boxes
Measure the product, not the box it is in now. A carton is built around what has to fit inside it, assembled — cap on, lid fitted, folded if it folds — at its widest point in each direction. Send those three numbers and say which is which.
- Length x width x height
- Internal, always. External dimensions include the board and are what the carrier measures, not what the product needs.
- Clearance
- 2–3 mm a side for a snug fit; more where an insert or void fill goes in. A carton cut exactly to the product is slow to pack and transmits every knock.
- Board thickness
- Heavier board takes internal space from the product. It matters most on small boxes, where four walls of 24pt is a real share of the cavity.
- Varies between batches?
- Glass, textiles, molded parts and cured soap all do. Measure several and build to the largest.
- Cutting tolerance
- Plus or minus 1 mm on folding board. Confirmed on a plain sample before the run.
- Units
- Metric or imperial, as long as you say which. Mixing them in one spec is where mistakes happen.
Not sure your numbers are right? Send the product dimensions rather than the box dimensions and we work the box out — the full method is in our guide to measuring for a box.
Interactive · five steps · no sign-up
Build your Auto Lock Boxes in 3D
Pick a shape, type a size, choose a board and a finish. The preview on the left redraws as you go, and the spec lands with us exactly as you set it.
Frequently asked questions
Got a question about auto lock boxes? The answers below cover what we get asked most. If yours is not here, send it with a brief, message us on WhatsApp, or call +1 503-461-4788 — we reply the same working day.
What is the minimum order?
100 cartons, glued and shipped flat.
Is it worth the extra cost?
Above about a thousand units, almost always. Below a few hundred, hand-folding a tuck base is cheaper.
Does it arrive assembled?
It arrives flat and becomes a box in one movement with the base already locked.
Auto bottom or snap-lock?
Snap-lock if a person folds a few a day; auto bottom if a line packs volume. Both beat a plain tuck base.
Can I print the bottom?
Not usefully — the base is overlapping glued flaps, so artwork there will not align.
What weight will the base hold?
Considerably more than a tuck bottom, because the load goes through a glue line rather than friction.
Is it worth the extra cost?
Above about a thousand units, almost always. Below a few hundred, hand-folding a tuck base is cheaper.
Does it arrive assembled?
It arrives flat and becomes a box in one movement, with the base already locked. That is the whole point of the build.
Auto bottom or snap-lock?
Snap-lock if a person folds a few a day; auto bottom if a line packs volume. Both are far stronger than a plain tuck base.
Can I print the bottom?
Not usefully. The base is overlapping glued flaps, so artwork there will not align.
Same range
