Sandblast Cabinet Oversize Hole Grommet Adapter

Parametric Oversized Hole Repair Bulkhead Grommet Adapter

I was upgrading my sandblasting cabinet from a siphon-style blaster to a metering-valve style and accidentally drilled a hole too large for the rubber grommet I needed to use, so I designed this fully parametric repair adapter to save the panel instead of remaking it.

In my specific use case, I accidentally drilled the cabinet hole out to 1 inch when I actually needed approximately a 7/8 inch hole for the rubber grommet I intended to use. The grommet itself has an inner diameter of approximately 11/16 inch and an outer flange diameter of approximately 1-1/4 inch.

This design creates a threaded bulkhead-style adapter that mounts into an oversized hole and provides a properly sized recessed seat for a standard rubber grommet.

The adapter is split into two printable pieces that are glued together after printing. This avoids difficult support geometry and also allows easier grommet installation. A matching threaded nut clamps the adapter securely to the panel, and an optional integrated O-ring groove can be enabled for sealing without silicone.

The O-ring groove can automatically select compatible O-rings from the Harbor Freight 397-piece Metric O-Ring Assortment Kit:
https://www.harborfreight.com/397-piece-metric-o-ring-assortment-67580.html

The entire design is parametric in OpenSCAD and uses the BOSL2 threading library.

Features

• Fully parametric
• Custom grommet dimensions
• Custom panel thickness
• Custom cabinet hole diameter
• Threaded bulkhead mounting system
• Optional integrated O-ring groove
• Split printable head design for easier support-free printing
• Hex wrench flats on both sides
• Automatically sized around the grommet geometry

Great For

• Sandblasting cabinets
• Enclosures
• Electrical panels
• Air lines
• Wire pass-throughs
• Vacuum systems
• Dust collection
• Automotive/firewall routing
• General panel repair

Adjustable Parameters

• Grommet inner diameter
• Grommet panel hole diameter
• Grommet outer flange diameter
• Panel thickness
• Existing oversized hole diameter
• Thread dimensions
• O-ring generation
• Manual O-ring sizing override

Printing Notes

• The adapter head is split into two printable pieces to avoid difficult support geometry.
• Glue the split head pieces together after printing and inserting the grommet.
• I printed mine in PLA, but use an appropriate filament for your environment and application.

Requirements

• OpenSCAD (for customization)
• BOSL2 library installed (for customization)

If this helps save a project after a bad hole measurement, then it did its job.