Two-row D-sub enclosure cutout and flange layout

Choose the actual two-row D-sub feedthrough before drawing its enclosure opening. Use its panel-mount drawing to define the cutout, mounting holes, wall thickness and sealing surfaces. A wide flange can cover machining variation, but it cannot correct misaligned fasteners or replace a specified gasket land.

For a two-row, 15-contact connection, confirm the DA shell size rather than relying on the loose description “DB15.” A three-row, 15-contact connector uses a different shell. Also confirm that a female-to-female adapter is designed for panel mounting; mating connectors alone do not establish that suitability.

What you need before drawing the opening

Collect the connector drawing, the mating cable assembly and the proposed mounting hardware. A photograph or overall adapter dimension is not enough.

You need these details:

• The shell designation, contact count, row arrangement and contact gender on each side.
• The recommended panel opening, including corner radii and mounting-hole locations.
• The flange outline and any separate sealing footprint.
• The permitted panel thickness and mounting orientation.
• The gasket specification, compression requirements and installation instructions, if supplied.
• The jackscrew, jackpost or through-fastener arrangement, including thread identification.
• The cable hood envelope, cable exit direction and minimum cable bend radius.
• The electrical pin mapping and intended signal service.

Choose between a purpose-built bulkhead connector, a panel-mount feedthrough and an adapter carried by a separate plate. An inline gender adapter may lack a usable sealing face or enough mounting-thread engagement through the enclosure wall.

A wide adapter plate is useful when the connector flange is narrow. However, it creates another joint to seal and another set of mounting holes.

The DB9 connector mounting article covers related D-sub mounting principles. Do not transfer its opening dimensions to a different shell size.

Lay out, cut and assemble the interface

1. Confirm the connector and electrical mapping.

   Match the physical sample to the exact drawing revision. Check both sides of a female-to-female feedthrough, including the positions of any jackposts. Confirm whether its contacts connect straight through or follow another mapping. Matching genders and shell sizes do not prove electrical compatibility.

   Establish which side faces outward before adding dimensions. A drawing viewed from the mating face can appear mirrored when transferred onto the inside wall.

2. Choose how the flange meets the wall.

   Decide whether the flange sits outside, inside or against an intermediate plate. Follow the connector manufacturer's specified mounting arrangement where one exists. This choice changes the opening geometry, gasket location and available thread engagement.

   Measure the actual wall thickness and include coatings, gaskets and washers in the mounting stack. Do not assume that supplied jackposts can accommodate any panel thickness. Verify that the hardware clamps the assembly without bottoming out or interfering with the mating connector.

3. Locate the whole connector assembly, not just its opening.

   Reserve room for the external hood, cable exit, internal termination and tools needed to secure the connector. Check the enclosure with its door open and closed. Rear-wall connectors also need clearance from the mounting surface and any supporting brackets.

   Include the space needed to withdraw the mating plug without sharply bending its cable. The 3D enclosure model checklist explains which geometry helps verify these clearances. For nearby controls, use the front-panel layout guidance to check access around the connector.

4. Dimension the opening and mounting holes from shared datums.

   Use stable enclosure edges or clearly identified drawing datums. Locate the connector centerline and mounting holes from those references. Avoid separate dimension chains that allow the opening and fasteners to drift in opposite directions.

   Use the recommended panel cutout, not the mating-shell outline. The shell, insulating body and flange may require different clearances. Keep hole diameter, thread designation and mounting pitch as separate callouts. Identify whether each mounting feature is a clearance hole, tapped hole or another specified feature.

5. Check the tolerance stack before increasing the opening.

   The minimum opening must clear the largest component section passing through it. The maximum opening must leave enough flange coverage and continuous sealing land. Check both limits, including positional error between the opening and flange.

   The following dimensions are an illustrative flat-flange calculation, not a D-sub cutout specification. They apply along one straight direction only.

   Item	Illustrative dimension	Purpose
   Largest component section	1.20 in [30.5 mm]	Establishes the minimum passage size
   Cutout target	1.24 in [31.5 mm]	Starting dimension for this example
   Cutout size tolerance	±0.02 in [±0.5 mm]	Gives a 1.22–1.26 in opening
   Minimum flange span	1.50 in [38.1 mm]	Establishes available coverage
   Maximum relative offset	0.02 in [0.5 mm]	Accounts for opening-to-flange displacement

   At the minimum opening, total clearance is 0.02 in [0.5 mm], or approximately 0.01 in [0.25 mm] per side when centered. At the maximum opening, minimum flange coverage on the displaced side is (1.50 − 1.26) / 2 − 0.02 = 0.10 in, approximately 2.5 mm.

   That coverage is not automatically usable gasket land. Flange radii, gasket grooves, mounting holes and unsupported edges can reduce it. Repeat the check vertically and around angled sides and corners. Obtain the actual sealing-land requirement from the selected connector or gasket design.

6. Make and inspect the opening.

   Before machining, check the drawing against the physical connector or a verified template. Isolate all energy sources and remove equipment that could be damaged by chips. Secure the workpiece and use a process suited to the enclosure material.

   For stainless work, follow the stainless enclosure cutting procedure for the machining fundamentals. Deburr both faces without enlarging the opening beyond its tolerance. Remove chips completely and inspect the flange seating area for distortion or deep scratches. Trial-fit the connector without forcing it through the opening.

7. Seal every path through the assembly.

   A perimeter gasket seals only the interface it contacts. It does not seal an ordinary D-sub connector's contact insert, shell seams or unmated face. Check whether environmental protection requires a particular mating plug, protective cap or mounting orientation.

   Our enclosures are rated NEMA 4X / IP66 by the manufacturer; not UL listed. That statement does not establish the rating of a modified assembly. Review the connector, gasket, fastener penetrations and installation together before claiming environmental protection.

   If you use a separate adapter plate, assess both the plate-to-wall and connector-to-plate joints. Keep gasket support continuous and use the specified compression method. Do not substitute an arbitrary bead of sealant for documented connector installation requirements.

8. Secure the wiring independently of the mating connection.

   Provide cable support so cable weight and repeated handling do not load the feedthrough or distort its flange. Keep the cable bend within its manufacturer's limits. Ensure internal conductors cannot rub against the cut edge or become trapped by the door.

   Follow the equipment's shield and bonding requirements rather than assuming the connector shell provides the required connection. With equipment disconnected, verify the feedthrough mapping before reconnecting signal circuits. Fit and secure the mating connector using its specified hardware.

Checks after assembly

Inspect the completed interface before returning the panel to service. A connector that fits loosely in an oversized opening may still hide inadequate sealing support.

• Confirm that the flange sits flat without rocking or visible bending.
• Check that the gasket remains supported around its full perimeter.
• Verify fastener engagement, tightening requirements and clearance from internal parts.
• Confirm the cable hood seats fully before its screws reach their travel limit.
• Check that the external plug can be removed with the enclosure installed.
• Inspect the interior for chips, sharp edges and trapped conductors.
• Verify contact mapping and required shield or bonding connections.
• Confirm the documented protection requirements in both mated and unmated conditions.

Use the applicable manufacturer inspection procedure and the project's approved environmental verification process. Do not apply water to energized equipment as an improvised leak test. A successful fit check alone does not demonstrate an enclosure rating.

Mistakes that cost the rating

Buying by contact count alone. Two connectors can each have 15 contacts while using different shell sizes and mounting geometry. Specify rows, shell designation and exact component identification.

Using flange overlap as the machining tolerance. A flange can hide a gap while leaving the gasket unsupported. Define an acceptable opening before cutting, rather than enlarging it until the connector fits.

Leaving positional error out of the calculation. Correct opening dimensions do not help when the mounting holes shift the flange toward one edge. Control the opening and fastener pattern together.

Treating a gender adapter as a sealed bulkhead. An adapter may provide electrical continuity without any environmental sealing. Select documented protection for the actual assembled and operating condition.

Correcting a warped flange with more torque. Excess tightening can distort the plate, damage hardware or unevenly compress the gasket. Correct the fit and follow the specified assembly requirements.

Adding an adapter plate without reviewing its joints. A wider plate may improve coverage, but its perimeter and mounting holes create additional potential leak paths.

What to send for the enclosure drawing

Send the exact connector drawing and identify the outward-facing side. Include the required cutout, mounting pattern, tolerances, wall thickness limits and gasket footprint. Add the cable hood envelope and rear withdrawal clearance, not just the shell dimensions.

For an adapter plate, show its material, thickness, attachment method and both sealing interfaces. Mark which dimensions come from the connector manufacturer and which describe your installation requirements.

The cutout designer can lay out openings on catalog or custom enclosure sizes. Use the custom stainless enclosure and cutout information when the body dimensions or interface need drawing-based review.

Before approval, use the enclosure drawing verification checklist to confirm orientation, mounting access and the final dimension set. Resolve the connector and seal design before releasing the enclosure opening for fabrication.

Enclosures for this job

Catalog sizes that suit the job this article answers, picked from its subject; open one for its full specifications.

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