Ametek, US Gauge, and 117 Multimeters: A Quality Manager's FAQ on Process Instruments and Test Equipment Rental

I review incoming instruments and rental packages before they reach our engineers. Roughly 200 items a year. I've rejected about 18% of first deliveries in 2024 because of calibration certificate gaps, mismatched specs, or packaging damage. So this isn't theory. These are the questions I get from project managers, lab techs, and buyers when they're specifying Ametek gear or renting test equipment.

Here's what I'll cover:

• What Ametek actually makes
• When renting Ametek electronic test equipment makes sense
• What to check on Ametek US Gauge pressure gauges
• What a 117 multimeter is—and isn't
• Megger vs multimeter
• Calibration traps

What does Ametek actually make, and why does it matter for process instruments?

Ametek is a broad instrumentation manufacturer. Under its umbrella, you'll find pressure gauges, viscometers, thermometers, sensors, thermal cameras, and process analytical instruments. The brand that matters depends on the job. US Gauge covers pressure gauges. Jofra covers calibration. Brookfield covers viscometers. Crystal Engineering covers pressure calibrators. If you're buying process instruments, the Ametek name is less useful than the sub-brand and model number.

It's tempting to think all Ametek products share one spec sheet. They do not. The company operates as a portfolio of specialized brands. That's usually good—you get deep expertise—but it means your purchase order needs the exact sub-brand, model, range, process connection, and accuracy class. I've seen a PO for 'Ametek pressure gauge' turn into a 2.5-inch dry gauge when the line needed a 4.5-inch liquid-filled gauge with 0.5% accuracy. (The vendor blamed the vague PO. Fair enough.)

Is Ametek electronic test equipment rental worth it, or should I buy?

Rental usually wins for short projects, one-off calibrations, or when you need a capability you'll use twice a year. Buying wins when you need it weekly, when calibration downtime is unacceptable, or when the asset has a long service life. The spreadsheet might say buy after seven months. My gut says check your project timeline first.

We ran that math on a pressure calibrator. The numbers said buying was cheaper after seven months. Something felt off about the project schedule. We rented. The project wrapped in three months. Buying would have left us with a $12,000 asset gathering dust and needing annual calibration. To be fair, if your work is steady, buying is often the better long-term call. But rental gives you flexibility and access to newer firmware without capital approval.

Here's something vendors won't tell you: rental calibration certificates are not all equal. Some are certificates of conformance. Some are ISO/IEC 17025 accredited. If your quality system requires traceability, ask for the actual certificate before the unit ships. I've rejected rentals because the certificate listed the wrong serial number (which, honestly, is a rookie mistake).

What should I check before buying Ametek US Gauge pressure gauges?

US Gauge pressure gauges are workhorses, but they're not all the same. Check these before you order:

• Dial size: 2.5-inch for tight panels, 4.5-inch for readability and lower parallax.
• Accuracy class: 1% or 2% is common for general service. 0.5% or better for critical process readings.
• Connection: 1/4 NPT, 1/2 NPT, or SAE. Wrong connection equals leak or adapter stack.
• Fill: Dry, glycerin-filled, or silicone-filled. Liquid fill dampens vibration and pulsation.
• Case material: Steel, stainless steel, or phenolic. Washdown areas need stainless or sealed cases.

What most people don't realize is that the gauge accuracy class applies to the full span, not the reading. A 1% gauge on a 0-100 psi span can be off by 1 psi anywhere on the dial. If you're reading 5 psi, that's a 20% error. Choose the span based on your normal operating point, not the maximum pressure you might see once.

What is a 117 multimeter, and who actually needs one?

When people say 117 multimeter, they usually mean the Fluke 117. It's a True RMS multimeter designed for commercial electricians. It measures AC/DC voltage, resistance, continuity, capacitance, and includes non-contact voltage detection. It does not measure current directly with a clamp; you need an accessory for that. It also does not perform insulation resistance testing.

Who needs it? Electricians doing commercial troubleshooting, facilities teams checking circuits, and anyone who needs a reliable True RMS meter for non-linear loads. Who doesn't? If you're doing electronics bench work, a 117 is overkill in the wrong direction—you'd want more resolution and lower current ranges. If you're testing motors and cables, you need an insulation tester, not a 117. I keep a 117-style meter in our tool crib, but I do not use it for insulation checks. That's a different tool.

Megger vs multimeter: what's the difference and which do I need?

A multimeter measures voltage, current, and resistance on live or powered-down circuits. A megger—more accurately, an insulation resistance tester—applies a high DC voltage (often 250 V, 500 V, or 1000 V) to measure insulation resistance in megohms. The names get used loosely. Megger is a brand, but many people say megger for any insulation tester.

It's tempting to think a megger is just a multimeter with a higher resistance range. But insulation testing is about applying a controlled high voltage over time, then reading leakage current. A multimeter's ohmmeter uses a low voltage and cannot stress insulation the same way. For motors, cables, switchgear, and transformers, use an insulation tester. For checking whether a circuit is live, measuring voltage drop, or confirming continuity, use a multimeter.

Neither replaces the other. I've seen techs try to use a multimeter to prove a motor winding is good. It reads continuity, so they think it's fine. The insulation could still be degraded and fail under load. That's a costly assumption.

How do I verify calibration and avoid spec mismatch on process instruments?

Calibration verification is where quality lives or dies. Start with the certificate. It should list the instrument serial number, calibration date, due date, environmental conditions, and the standard used. The standard should be traceable to a national lab. If you require ISO/IEC 17025, say so in the PO. Do not assume. As of January 2025, accreditation is a common audit requirement, but verify your specific quality system requirements before you accept a certificate.

Then check the as-found and as-left data. A certificate that only says pass is not enough for a quality audit. You want numbers. If the instrument was out of tolerance, the certificate should show how far out and what was adjusted. I rejected a batch of process instruments in 2023 because the certificates had no as-found data. The vendor claimed it was within industry standard. Our audit standard did not accept that. They redid the calibration at their cost.

Finally, match the instrument to the process. A pressure gauge with a 0-15 psi range is great for a 10 psi line. It's useless for a 200 psi line. A thermometer with the wrong stem length reads the wrong temperature. A viscometer with the wrong spindle range gives meaningless numbers. The spec sheet is not a suggestion.

What's the most common mistake when renting Ametek electronic test equipment?

Renting the wrong accuracy class or assuming the rental includes accessories. I've seen a rental pressure calibrator arrive without the required hand pump. The project stalled for two days waiting on a $300 part. The rental fee was lower than the competitor, but the downtime cost more than the savings.

Also, confirm the rental period. Some vendors count transit days. Some charge for weekends. Some include calibration in the rate; others add it as a line item. Ask for the total landed cost, not the daily rate. The numbers might say Vendor A is cheaper. My gut says read the terms. Usually, the vendor with clear terms is the better partner, even if the daily rate is 5% higher.

If you're specifying Ametek process instruments or renting test gear, write the specs down. Include the sub-brand, model, range, accuracy, calibration requirements, and accessory list. An informed PO prevents a rejected delivery. And an informed customer asks better questions. I'd rather spend 10 minutes explaining options than deal with a mismatched expectation three weeks later.