Threads & Standards

NPT, G (BSP), ZG(R) BSPT and metric thread guides for stainless steel fittings and valve buyers — identify the thread before you send a factory RFQ.

Flanged hex socket plug — a flanged joint seals on a face, the straight-thread way

NPT vs NPS Threads: The One-Letter Difference That Decides How the Joint Seals

NPT vs NPS: same 60° form and TPI, but one tapers and one runs straight — so NPT seals on the thread and NPS never does. Variant decoder, interchange rules, and the NPS double meaning.

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Hex head plug with a male tapered pipe thread ready for caliper and pitch gauge measurement

How to Measure NPT Fittings: A Step-by-Step Guide with a Caliper and Pitch Gauge

Measure NPT fittings with two hand tools: read the major diameter on the first full thread, count TPI, confirm the taper — then match the reading to the chart, not the nominal size.

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Reducing compression tees joining two different tube outside diameters

Compression Fitting Sizes: OD vs ID Ordering Rules

Compression fitting sizes follow the tube OD, never the ID. The 3/16 trap, tube versus pipe ordering grammar, and a five-step checklist before you order.

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Metric stainless tube fitting body for the millimeter sizing system

Metric Compression Fittings: The 6–25 mm Size Walkthrough

Metric compression fittings: the 6–25 mm tube range, why metric and inch ferrules never mix, M-thread versus G-thread tails, and DIN 2353 size logic.

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Stainless pipe elbow fitting where wall thickness follows the schedule

Pipe Schedule Numbers: Why 40 and 80 Keep Changing Your Wall

Pipe schedule numbers explained: why Schedule 40 and 80 change the wall but not the OD, the STD and XS equivalents, stainless S-suffix, and threading limits.

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Small stainless union fitting in the dash-sized tube range

Dash Numbers on Drawings: Reading -4 to -32 Without a Chart

Dash numbers decoded: dash ÷ 16 = inches, -6 is 3/8 inch tube OD not pipe size, the SAE J514 lineage, and the metric-twin trap.

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Stainless fitting end with sealing face, the part a BSPP washer seals against

BSP Thread Seal: Why BSPP Needs a Washer and BSPT Does Not

BSPP vs BSPT sealing: why parallel G threads need a washer or bonded seal, tapered R threads seal on the flank, plus bonded seal dimensions by size.

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Male and female thread ends on a stainless adapter for identification

How to Identify NPT vs BSP Threads: The 5-Minute Bench Test

Identify NPT vs BSP threads in five minutes: gauge the TPI, measure the major OD, check form and taper against a verified chart — then write it on the RFQ.

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Stainless male-to-female straight adapter converting between thread and tube ends

The Dash Size Chart: How -4 to -32 Notation Maps to Real Dimensions

Dash size chart: how -4 to -32 dash numbers map to fractional inch and millimeter tube sizes in SAE/JIC hydraulic fittings, and how to read a spec line.

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Tri-clamp ferrule end on a stainless corrugated hose assembly

What Are Tri-Clamp Fittings and How Are They Measured?

Tri-clamp (tri-clover) sanitary fittings explained: why sizes follow tube OD, a full ferrule flange size chart, clamp types and pressure ratings, and gasket rules.

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Instrumentation panel with threaded stainless fittings

NPT vs G (BSP) Threads on Stainless Fittings

How to pick NPT, G/BSP or metric threads for stainless steel compression fittings and valves — factory RFQ checklist from FerruleX.

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