# SMA and RP-SMA bulkhead jack: thread and D-flat panel cutout

> What size hole does an SMA bulkhead connector need?

- Category: Electronic components › Connectors
- Kind: Standard part
- Basis: Maker drawings (Samtec, Amphenol RF)
- Page: https://xemstudio.com/objects/sma-bulkhead-connector/ · JSON: https://xemstudio.com/api/geometry?object=sma-bulkhead-connector · Plain text: https://xemstudio.com/objects/sma-bulkhead-connector/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- FPV antennas and VTX pigtails pass through a frame or canopy on an SMA (or RP-SMA, same body and thread, reversed pin) bulkhead jack.
- Both maker drawings give the recommended mounting hole as a 6.60 mm (.260 in) hole with one D flat paired with 6.10 mm (.240 in); the text of the drawings does not label 6.10 explicitly as the flat-to-opposite-edge distance, so no cutout file is drawn from it. Check the drawing of your exact part before cutting.
- Panel thickness limits differ by part (3.80 mm max on the Samtec part); long-thread bulkheads take thicker panels.
- U.FL pigtails to SMA bulkheads are on the U.FL page.

## Sizes

| dimension | value |
|---|---|
| coupling thread | 1/4-36 UNS-2A (jack) / 1/4-36 UNS-2B (nut), interface MIL-STD-348 series SMA |
| recommended panel cutout (Samtec) | 6.60 mm (.260 in) round hole and 6.10 mm (.240 in) dimension, with a single D flat |
| max panel thickness (Samtec SMA-J-C-X-ST-BH4) | 3.80 mm (.150 in) |
| hex (Samtec) | 8.00 mm (.315 in) REF |
| Amphenol RF 132397 cutout | same 6.60 / 6.10 pair, one 'D' flat |

## Where the files are

- Samtec: [SMA-J-C-X-ST-BH4 bulkhead jack drawing (recommended panel cutout)](https://suddendocs.samtec.com/prints/sma-j-c-x-st-bh4-mkt.pdf) — web — Publisher's page; dimensions are facts
- Amphenol RF (via TestEquity): [SMA straight bulkhead jack, front mount, customer drawing 132397](https://assets.testequity.com/te1/Documents/pdf/amphenol/amphenol_132397-connector_customer-drawing.pdf) — web — Publisher's page; dimensions are facts

## Questions

**What thread is SMA?**

1/4-36 UNS (2A on the jack, 2B in the nut).

**What hole does an SMA bulkhead need?**

A 6.60 mm (.260 in) hole with one D flat, paired with 6.10 mm (.240 in) on the Samtec and Amphenol drawings; check your part's drawing.

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