3/4-260H 0.260" Bore Diameter Threaded Heavy Duty Thermowells

Supported Applications

The Omega Series 260H is a heavy-duty threaded thermowell designed for temperature measurement applications requiring protection of sensing elements. The series accommodates standard length, ¼" bimetal thermometers, #20-gage thermocouple elements, and unarmored liquid-in-glass test thermometers. It supports maximum temperature-sensing element diameters up to 0.252".

Documented application contexts include:

• Chemical baths
• Corrosion-resistant environments (via material selection)
• Process control utilizing color-coded sensors

Operating Conditions & Performance

The Series 260H features a bore diameter of 0.260" ±0.002" with an internal pipe thread allowance that accepts both NPT and NPS male threads (1/2 NPSM). Pressure ratings are dependent on material selection, temperature, and specific model configuration.

Pressure-Temperature Ratings in lb per Square Inch vary by material:

• Brass: 5300 psi at 70°F; 4750 psi at 200°F; 1100 psi at 400°F.
• Carbon Steel (C-1018): 5950 psi at 70°F; 5750 psi at 200°F; 5450 psi at 400°F; 5250 psi at 600°F; 4000 psi at 800°F; 1750 psi at 1000°F.
• A.I.S.I. 304: 7800 psi at 70°F, 7050 psi at 200°F (reduced to 6400 psi at 400°F); down to 5190 psi at 1000°F; 1875 psi at 1200°F.
• A.I.S.I. 316: 7800 psi at 70°F and 200°F (reduced to 7250 psi at 400°F); down to 5800 psi at 1000°F; 2720 psi at 1200°F.
• Monel: 7450 psi at 70°F; 6850 psi at 200°F; down to 5940 psi at 800°F; 1750 psi at 1000°F.

Note: Ratings marked with "—" indicate no data provided for that temperature in the source table. The series is manufactured in the USA.

Configuration Options

The Series 260H offers configurable dimensions and materials to meet specific installation requirements. Key selection parameters include external thread size, stem length (A), insertion length (U), shank diameter (Q), and wetted material code.

Dimensions & Geometry

• Bore: 0.260" ±0.002" for all models.
• Insertion Lengths (U): Available in increments from 2½" to 22½" (specific lengths: 2½", 4½", 7½", 10½", 13½", 16½", 22½").
• Stem Lengths (A): Available in increments from 4" to 24" (specific lengths: 4, 6, 9, 12, 15, 18, 24).
• Shank Diameter (Q): Varies by thread size group; 7/8" for ¾ NPT models and 1⅛" for 1 NPT models.

Process Connections & Materials

• External Threads: Available in ¾ NPT or 1 NPT. The internal pipe thread accepts both NPT and NPS male threads (designated as 1/2 NPSM).
• Wetted Materials:
    • Brass (ASTM B-16)
    • Carbon Steel (C-1018)
    •  A.I.S.I. 304 Stainless Steel
    •  A.I.S.I. 316 Stainless Steel
    • Monel®
• Protective Coatings: PFA and Epoxy coatings are available; consult the Sales Department for details.

Options & Accessories

• Caps & Chains: Brass cap with chain (suffix "-CC-Brass") or 304 SS cap with chain (suffix "-CC"). Additional cost applies.
• Sensors: Compatible with OMEGA® NB1, NB2; PR-12, PR-14, and NPT-style probes, as well as DialTemp™ Thermometers. Color-coded sensors are supported for process control.

Key Product Differences

Variants within the Series 260H differ primarily by external thread size (¾ NPT vs. 1 NPT), insertion length, stem length, and material composition. The model number structure follows the format: <Ext Thread>-<Model Base>-U<Insert Length>-(<Material Code>). For example, a part numbered "3/4-260H-U71/2-304" denotes a ¾ NPT external thread with a 7½" insertion length and A.I.S.I. 304 stainless steel construction.

Material codes in the ordering system specify: '304' for 304 stainless steel, '316' for 316 stainless steel, 'CS' for carbon steel, and 'BRASS' for brass. Metric models are noted as available via omega.com but specific metric dimensions are not detailed in this series data sheet.