King Nutronics Model 3750 Portable Calibrator — field‑ready kit
The Model 3750 is the U.S. Navy’s shipboard hand‑pump of choice. Dual‑piston technology lets you jump from rapid pressure build‑up to fingertip vernier tweaks of 0.001 psi, whether you’re pulling ‑28 in Hg vacuum, dialing in 0‑500 psi pneumatics, or generating up to 6 600 psi hydraulically.
What’s in this sale (see photos)
| Qty | Item |
|---|---|
| 1 | 3750 heavy‑duty hand‑pump (6 K psi version) with neck‑strap |
| 1 | 8 oz hydraulic reservoir bottle, quick‑coupled |
| 1 | 3 ft braided AN‑4 test hose with ¼‑NPT male quick‑disconnect |
| 1 | Bubble‑tight bleed / fine‑relief valve |
| 1 | Analog reference gauge 0‑6 K psi (stainless‑case, glycerin fill) |
| 1 | Low‑range compound gauge 30 in Hg V to 0‑500 psi |
| 1 | Accessory & fitting kit (O‑rings, seals, adapters) |
| 1 | Custom foam‑fitted soft case w/ shoulder strap & exterior pouch |
(If you have extra gauges or different contents, adjust the table above.)
Condition
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Excellent used — pump cycles smoothly, holds pressure for 10 min at 5 000 psi and 28 in Hg during bench check.
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Gauges zero correctly; no cracked lenses.
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Foam and outer bag clean; light scuffs on zipper pulls.
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Fresh set of O‑rings and Schrader‑type fluid trap installed May 2025.
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Calibration certificates not included. Kit sold exactly as pictured.
Key features & benefits
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Four‑in‑one: vacuum, low‑pressure pneumatics, high‑pressure pneumatics, and hydraulics from one rugged pump.
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Quick‑twist selector switches instantly between pressure & vacuum.
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“No‑crush” clutch on the bleed knob prevents over‑tightening and extends seat life.
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All wetted parts are 316 SS or protected alloys for long service life in aggressive environments.