Need to join a 13/16"-28 UN connector port to an M20×1.5 cable gland or enclosure entry — and can't find the adapter in any catalog? We machine it to order in 304 stainless steel: 13/16-28 male one end, M20×1.5 female the other, sealed or plain, through-bored for your cable. From a sketch or sample, no CAD, one piece up. Get a quote →
Two threads that meet only in a custom part
13/16"-28 UN (often marked UNS) is the housing thread on IP67 waterproof RJ45 jacks, HDMI bulkhead couplers and industrial circular panel connectors — the threaded metal shells used on outdoor cabinets, marine electronics and machine housings. M20×1.5 is the metric standard for cable glands, enclosure knockouts and equipment entries across European-style gear. Sooner or later the two meet: a gland has to go where a connector was, or a connector has to mount in a metric knockout.
No catalog crosses that line. Gland makers stock metric-to-metric reducers (M25→M20) and PG or NPT conversions — never the UN-to-metric crossover. And there's a physical reason: M20's major diameter is 20.0 mm and 13/16" is 20.64 mm. The threads are so close in size that a thin nesting bushing would have no wall left. The only way to build this conversion is the way we machine it — turned from solid bar, with the two threads in series along the axis, a proper hex body between them, and the bore, seal and lengths cut to your installation.
Check the pitch before you order. The 13/16" family exists in several pitches; the connector-industry thread is the fine 28 TPI version. If your part came off an IP67 RJ45, HDMI or circular connector it is almost certainly 13/16"-28 — but count the threads or send us the part, and we gauge both ends before anything is cut.
Forms we machine
Standard: UN Male × Metric Female
13/16"-28 male screws into the connector port or coupling nut; M20×1.5 female accepts a standard cable gland.
Reverse: Metric Male × UN Female
M20×1.5 male mounts in an enclosure knockout; 13/16"-28 female accepts the connector shell.
Bulkhead / Jam-Nut Version
Long male thread with lock nut and O-ring — carries the conversion through a panel up to 8 mm thick.
Through-Bored for Cable
Clear bore up to ~15 mm so a terminated plug or cable passes straight through the adapter.
Specification
| Feature | Spec | Notes |
|---|---|---|
| UN end | 13/16"-28 UN / UNS, class 2A male | Ø20.64 mm — gauged before shipping |
| Metric end | M20×1.5, 6H female | Fits standard metric cable glands |
| Seal | O-ring groove · flat sealing face · sealing washer seat | Keeps the IP rating at the joint |
| Material | 304 stainless steel · 316 stainless · nickel-plated brass · 6061 aluminum | 304 is the standard build |
| Body | Hex with wrench flats · knurled ring on request | Standard spanner sizes |
| Bore | Solid · through-bore to ~15 mm | Sized to your cable or plug |
| Variants | Other pitches & sizes: M16×1.5, M25×1.5, PG13.5, 1/2" NPT ends | Any combination, same part |
Where it's used
- Retrofitting outdoor cabinets — replace a waterproof RJ45 or HDMI feed-through with an M20 cable gland without re-drilling the panel.
- Mounting IP67 connectors in metric enclosures — the reverse form puts a 13/16-28 connector shell into a standard M20 knockout.
- Marine & coastal electronics — 304 or 316 stainless keeps the joint from seizing and corroding where nickel-plated zinc parts fail.
- Machine builders & panel shops — one gauged adapter instead of re-machining a housing when the connector spec changes mid-project.
Related adapters we machine
Frequently asked
Is 13/16"-28 the thread on waterproof RJ45 and HDMI panel connectors?
Yes. 13/16"-28 UN (sometimes marked UNS) is the standard housing thread on IP67 RJ45 jacks, HDMI bulkhead couplers and many industrial circular connectors. The 13/16 family also exists in coarser pitches, so confirm yours is 28 TPI — we gauge both ends before machining.
Can I fit an M20×1.5 cable gland into a 13/16-28 connector port?
Yes — that's exactly what this adapter does. The 13/16"-28 male end screws into the existing port or coupling nut, and the M20×1.5 female end accepts a standard metric gland. For sealed installations we add an O-ring groove or sealing face at the shoulder.
Why is there no off-the-shelf bushing for this conversion?
Because M20 (20.0 mm) and 13/16" (20.64 mm) are almost the same diameter, a nesting bushing would have nearly zero wall. The part has to be machined from solid with the threads in series — which is why catalogs stop at metric-to-metric gland reducers and this one is made to order. More on joining two different threads →
What materials, and what's the minimum order?
304 stainless steel as standard, 316 stainless for marine and chemical exposure, nickel-plated brass for EMC-bonded glands, and 6061 aluminum where weight matters. MOQ one piece, from a sketch, photo or sample — no CAD needed.
Tell us the two ends and the duty. A photo of the connector port, the gland you want to fit, or just the callouts (e.g. "13/16-28 male → M20×1.5 female, outdoor cabinet, 304, cable pass-through Ø12 mm"). Free drawing, quote in 24–48 hours. Get a quote →