Porthole Installation Guide A:
With concealed fastening

This guide describes the installation of portholes and vision panels with concealed fastening. This version is designed for frames made of aluminium or stainless steel L-profile.

The key factors for clean installation are a precisely centred mounting frame, evenly adjusted stud bolts, a glass pane positioned without tension, and the controlled insertion of the glazing wedge gaskets.
What matters during installation

Installation diagram explained interactively

The numbers in the technical drawing correspond to the installation steps. Click or touch a point to jump directly to the relevant step.
Tip for touch devices: Tap a point for details • press and hold to jump

Technical drawing for the installation guide for portholes and vision panels version A

Installation in seven clear steps

From the central alignment of the mounting frame to the finished glazing: the following steps guide you cleanly through the installation of Version A with concealed fastening.

01

Insert the mounting frame centrally

Insert the mounting frame with right-hand thread into the prepared cut-out and align it centrally. Then wedge the frame neatly in place so that it cannot slip during the subsequent installation steps.

Important: The mounting frame must sit centrally and be held securely. Any shift at this stage will later affect the glass position, gap clearance and gasket seating.
02

Screw in the stud bolts evenly

Screw four stud bolts into the mounting frame using the side with the right-hand thread. The pointed side of each stud bolt has the left-hand thread. Each stud bolt is screwed in by no more than one thread pitch.

Then adjust all four stud bolts to exactly the same height using a depth gauge, for example the depth gauge of a caliper.

Precision point: The identical height of all four stud bolts is essential so that the glazing frame later sits evenly and does not tilt.
03

Clamp the glass pane centrally

Insert the glass pane centrally and loosely clamp it with three to four small wooden blocks. The blocks are secured with silicone to prevent them from slipping.

Recommended dimensions for the spacer blocks:

  • Width: 10 to 15 mm
  • Length: according to the leaf thickness
  • Height: approximately half the clearance between glass and cut-out
Installation goal: The glass pane should be held centrally and loosely. It must not be under tension, as this could later cause pressure marks or stress in the glass.
04

Fit and screw on the glazing frame

Place the glazing frame onto the stud bolts. Then screw both frames together evenly using the supplied angled 6 mm open-end wrench.

Start with the stud bolt whose tip first makes contact with the left-hand thread of the mounting frame.

Clean sequence: The screw connection should be tightened evenly. This allows the mounting frame and glazing frame to come together in a controlled manner without putting one-sided stress on the frame.
05

Set the gap clearance for the glazing gasket

Half the distance between the glazing frame and the glass pane is set as the gap clearance for the glazing gasket between the glass pane and the mounting frame. Suitable glazing spacer blocks are used for this purpose.

Suitable glazing spacer blocks:

  • Red: 2 mm
  • Green: 3 mm
  • Yellow: 4 mm
  • Blue: 5 mm
Professional point: The gap clearance should be as even as possible all around. This makes it easier to insert the wedge gasket and ensures clean glazing.
06

Insert the glazing wedge gasket on the glazing frame

Insert the supplied glazing wedge gasket between the glass pane and the glazing frame. Work evenly and make sure that the gasket sits cleanly in the intended joint.

Clean execution: The wedge gasket should not be twisted, squeezed or overstretched in sections. Calm, even insertion improves both fit and appearance.
07

Insert the wedge gasket on the mounting frame and remove spacer blocks

Now insert the glazing wedge gasket between the glass pane and the mounting frame. The glazing spacer blocks inserted in step 5 are removed again during this process.

Final check: After removing the spacer blocks, the glass pane should sit centrally, securely and without visible stress in the frame.
!

Do not overtighten the screws

The screws may only be tightened until both metal rings sit cleanly against each other. The maximum torque is 1.5 Nm.

If the screws are tightened too much, the welded internal threaded bushings may tear off or indentation marks may appear on the visible surfaces.

The result

When installed correctly, the result is a cleanly framed vision panel with a centrally positioned glass pane, even glazing and concealed fastening for a particularly calm, high-quality visible surface.

Further technical information

Back to the porthole overview, to the glazing options or to the price inquiry for portholes.

Gesco metall Biegetechnik

Precision in Perfection

GESCO-metall GmbH
Bellstr. 3a
D-92421 Schwandorf
Phone: +49 9431 74 63 – 0
Fax: +49 9431 74 63 – 20
Mail: info@gesco-biegetechnik.de

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