SnipFold

Expandable Gusset Envelope Pouch

A tuck-closed envelope pouch with inward V-fold side bellows, a shaped depth-bearing bottom and a slotted front closure.

Materials

  • 140-170 gsm paper
  • Scissors
  • Craft knife and cutting mat
  • Ruler and blunt scoring tool
  • PVA glue

Finished size: 90 x 18 x 65 mm closed; side leaves 12.04 mm each

Steps

CutValley foldMountain foldGlue area

  1. Cut three pieces and the slot

    Print at actual size and check the 50 mm ruler. Cut P1, P2 and P3 once each. Remove the 24 x 1 mm rectangular hole in P1 with a knife; do not merely score it. Preserve all attached flanges.

  2. Score the body and lid

    P1 front is the 90 x 65 mm panel containing the slot. The 18 mm band beside it is the base; the other tall panel is the back. Fold front and back up 90 degrees from the base. Precrease the 18 mm top bridge, tapered cover and 20 mm-wide tongue. The tongue eventually points inward, opposite to the cover turn.

  3. Form the two inward bellows

    Score P2 and P3. Fold each center line into an inward-pointing ridge, with its two equal 12.04 mm leaves making a V. Place P2 on the left and P3 on the right: endpoints are 18 mm apart and the ridge sits 8 mm inside the pouch. Fold each long 6 mm flange onto the inner front/back wall plane. Fold both short mitred 3 mm bottom flanges horizontally toward the base interior. Follow these spatial directions if the printed side is reversed.

  4. Glue gussets to the base first

    Leave front and back lowered for access. Seat the two bottom edges of P2 along the left V-notch of P1; its ridge lands at the notch tip (8 mm inward, halfway across the depth). Glue its two 3 mm flanges onto the upper base surface. Repeat P3 at the right notch. Keep glue off the center creases and let these four small joints set.

  5. Close the front seams

    Raise the slotted front 90 degrees. Glue the front-facing 6 mm flange of P2 inside its left edge and the matching flange of P3 inside its right edge, from 3 mm above the base to the top rim. Align top edges at 65 mm. Hold each seam until set; do not glue the V leaves together.

  6. Close the back seams and dry

    Raise the back and glue the remaining two 6 mm flanges inside its edges. Keep the base flat and the inward gusset ridges parallel. Press the seams through the open mouth and allow all glue to dry before moving the bellows.

  7. Expand gently and tuck shut

    With the lid open, gently open and close the upper V folds; the glued bottom stays 18 mm deep. Return the mouth to 18 mm. Fold the top bridge across the mouth, then the tapered flap down the front by 22 mm. Flex the cover outward slightly, guide the 20 mm tongue through the 24 mm slot at 43 mm above the base, then seat it 8 mm inside, approximately horizontal. Do not glue the closure. Test fit with scrap paper before loading; physical performance is unverified.

Notes

The 3D model shows each piece in its finished, idealized shape; the exploded view only spreads the pieces apart. It is not a paper-physics simulation: curved shapes are forming guides, not exact physical folding or proof of developability, and intermediate fold shapes are not supplied.