From the Loftsmith Workshop

Secondary glazing turn button clips for 2-6 mm acrylic

Holds a sheet of acrylic against your window frame so you can add a second layer of glazing without drilling the plastic. Turn the knurled button a quarter turn and its arm swings over the edge to press the sheet down. Set the sheet thickness to match yours.

2 parts · 3 g · 32 × 22 × 9 mm

by Loftsmith Workshop

Small orange turn button with a ridged round knob and a flat arm, resting on a board beside a grey strip
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No adjustable sizes

Ask for the sizes you want to tweak, e.g. “make the width adjustable”.

Change it in the Studio

Parts

  • hub · PETG · Upside down, top face on the bed (printRotate 180, 0, 0), printed together with the button as one object

    Fixed part. Screws to the frame through a 4.5 mm clearance hole with an 8.9 mm 90-degree countersink, both shown in the Screw seat check. 15.2 mm across, 9 mm tall at the defaults. Print one hub and button set per clip: 14 sets for the default 900 x 700 mm panel.

  • button · PETG · Upside down, top face on the bed, in the same print group as the hub

    Turning lever with a fluted 22 mm boss. It is captured on the hub by a ridge with a flat ledge, which leaves 0.35 mm of axial play at the defaults. 32.4 x 21.9 x 9 mm at the defaults. PETG because a sunlit window gets warm enough for PLA to creep.

Print settings

Layer height
0.2 mm
Walls
2
Infill
15%
Supports
None
Notes
About 3 g and 14 min per clip at 2 walls and 15% infill (build-report estimate), so roughly 42 g and 3.3 h for the 14 clips of a 900 x 700 mm panel. For stiffer levers, 3 walls and 15% gives about 4 g and 19 min per clip. Print each hub and button as one object, upside down. The two bodies are separ

Hardware

  • Countersunk wood screw, 4 mm (No. 8) or 3.5 mm, about 25 mm long · One per clip. The hub has a 4.5 mm clearance hole and an 8.9 mm 90-degree countersink (Loftsmith catalog M4 sizes, shown in the Screw seat check). Use a screw that suits your frame material.
  • Self-adhesive foam seal strip, 1.5-4 mm thick (2 mm or more recommended), about 10 mm wide · Runs around the frame under the panel edge. Set the Seal thickness slider to its uncompressed thickness.
  • Acrylic or polycarbonate sheet, 2-6 mm · Cut so the panel lands on the seal with about 1.5 mm between its edge and each clip boss.

Assembly

  1. Stick the foam seal around the window frame face where the panel edge will land.
  2. Use the Clip layout check on the Check tab to mark the clip positions. The defaults give 4 clips along the top and bottom and 3 down each side, 60 mm in from the corners.
  3. Hold each clip on the frame with its boss about 1.5 mm from where the panel edge will sit, then screw it down through the hub with a 4 mm countersunk screw. The button stays free to turn.
  4. Turn every button 90 degrees so its lever runs along the panel edge.
  5. Set the panel on the seal. Its bottom edge rests on the bosses of the bottom clips. You can tuck the bottom edge under closed buttons first and then lower the top.
  6. Turn each lever back over the panel edge. The chamfer under the lever rides up onto the sheet. The button lifts to its ridge stop and the jaw squeezes the seal (0.50 mm at the defaults).
  7. To take the panel off, turn the levers 90 degrees and lift it away.

Good to know

  • There is no click detent. A closed lever is held only by friction from the seal pushing the button against its ridge stop. The Jaw check gives the squeeze left in the worst loaded pose: 0.50 mm at the defaults, designed as a quarter of the seal thickness with a 0.4 mm minimum (0.40 mm at the 1.5 mm
  • This is for vertical windows only. Don't use it on horizontal or overhead panels such as skylights or roof lights: there the panel's weight would hang from the levers and the ridge.
  • The loaded pose is a rigid-geometry calculation: the button is lifted to its ridge stop and rocked about its back edge. It does not model how much the parts or the foam flex. Strength was estimated for a 30 N push at each jaw and for the panel weight on the bottom clips. The fit and turning have not
  • A larger running gap turns more freely but lets the lever rise more. The jaw is lowered to compensate, and the Jaw check shows the lift for your settings (0.68 mm at the default 0.35 mm gap).
  • The panel must stay removable. Don't fit it to a window you need as a fire escape unless the clips can be opened quickly.
  • Each clip needs about 23.5 mm of flat frame face beyond the panel edge.
  • Large thick panels are heavy: 1600 x 1600 mm in 6 mm acrylic is about 18 kg. Use the closest spacing and sound screw fixings.
  • PLA is not recommended. A window in direct sun can soften it. Use PETG or ASA.
  • This design makes no claim about insulation or energy savings.
I printed this Remix

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