I'm the office administrator for a mid-size manufacturing company. I handle purchasing for our lab and production floor—roughly $400,000 in annual spend across 15 vendors, mostly on metrology and test equipment. I report to operations and finance, which means I get asked twice about every order: “Is it necessary?” and “Can we find it cheaper?”
So when our engineers asked for a new Renishaw TONiC encoder for a motion stage and the shop floor wanted a thermal camera, I had to compare new Renishaw systems against used test equipment. I'm going to look at four dimensions: measurement confidence, total cost, calibration, and support. In that order. This article is the comparison I wish someone had given me before I started.
What This Comparison Actually Covers
On one side: new Renishaw components—TONiC encoders, CMM probes, and the support that comes with them. On the other side: used test equipment—thermal imagers, pH meters, measurement gauges—often bought through resellers without a calibration certificate.
The comparison only makes sense if you define the measurement first. Are you aligning a precision stage to microns? Are you checking a coolant tank's pH? Are you looking for hot spots on a breaker panel? These are different worlds. The answer changes accordingly.
Dimension 1: Measurement Confidence
New Renishaw equipment earns a confidence that used equipment can't claim in the same way. A new TONiC encoder's interpolation error is documented. A new CMM probe's stylus geometry is specified. You know the starting point because it came from the factory.
Used test equipment is a black box. “Tested” in a reseller listing usually means it powered on. It doesn't mean it holds accuracy to spec. What most people don't realize is that “calibrated” on a used listing can simply mean someone put a sticker on the device—not that they ran it against a traceable reference.
I had this exact tension recently. The numbers said used was the right call—I want to say the price was 60% lower, but don't quote me on the exact figure. My gut said pass. Then I asked the seller for calibration data. They sent a photo of the front panel. That's it. We bought new.
Conclusion: if your measurement drives a quality decision, buy new. If you're only looking for a relative trend, used can be enough.
Dimension 2: Total Cost, Not Just Price
Used equipment wins on upfront price. That's not a debate. But price is only the first line of the budget.
When I account for calibration, repair, and the cost of being wrong, the gap gets smaller. A used TG298 thermal imaging camera might sell for 40% below list. If it's for a quick roof survey, that's a deal. If it's for electrical troubleshooting, a poor calibration could send someone toward a live panel with a false sense of certainty. (Should mention: I'm an admin, not an electrical engineer. But I've read enough near-miss reports to take that seriously.)
Also—and this is the part I keep reminding finance—downtime isn't in the PO. If a new Renishaw encoder fails (rare, but possible), you have warranty and a support line. If a used encoder from a reseller fails, you have a return window if you're lucky, then nothing. The total cost of a failed used component is the component price plus however many hours your engineer spends chasing the issue.
For calibration quotes, one of our vendors charged about 18% of the used purchase price to calibrate a thermal imager (this was back in 2023; as of January 2025, I'd verify current rates). On that basis, the savings starts shrinking fast.
Dimension 3: Calibration—Some You Can Do Yourself
This is where the smart buyer gets an edge. Not all calibration is the same.
How to calibrate an Extech pH meter
Take the Extech pH meter. If you buy one used, you can calibrate it yourself, and you should. The process is straightforward: rinse the electrode in distilled water, place it in a pH 4.01 buffer, wait for the reading to stabilize, and adjust. Rinse again, then repeat with pH 7.00 or 6.86. For a third point, use pH 10.01. The manual—still downloadable from Extech's website (as of January 2025, at least)—walks through the procedure. What most people miss: the electrode needs to be hydrated. A dry electrode won't calibrate no matter how many buffers you cycle through.
That's the “cheap and easy” end of calibration. A Renishaw CMM probe or TONiC encoder is a different world. You can't run an encoder through a buffer solution. It needs mechanical and electrical verification against standards—often referencing ISO 10360-2 for CMM performance—and the artifacts needed for that cost more than the encoder itself. If you buy new, the traceable calibration comes as part of the system. If you buy used, you're hoping the previous owner treated it well. “Pulled from a working machine” is not a traceable certificate.
Here's something vendors won't tell you: “pulled from a working machine” often means “we didn't test it after removal.” It might be fine. Or it might be the reason they removed it.
Dimension 4: Support When Something Goes Wrong
New Renishaw support is the quiet value. It doesn't show up in the spec sheet, but it appears when you're commissioning a TONiC encoder and the readhead is showing a signal level you've never seen. You call the application engineer. They answer.
With used test equipment, the support is usually a “no returns after 14 days” email. For a pH meter, that's acceptable. For a precision encoder, that's miserable.
One caveat: we've also bought used equipment that didn't need support. Our field engineer picked up a used TG298 thermal imaging camera from a reseller, verified it against an IR source, and it's been serving us for two years. But we had the internal skill to verify it. If you don't have that skill, the warranty on new equipment is worth the premium.
The Verdict (and the Exception)
Buy new Renishaw when the measurement result determines whether a part ships to a customer. Buy used test equipment when the device is a diagnostic aid, not a gatekeeper.
- New Renishaw TONiC encoders and CMM probes: if your tolerance stack depends on them, buy new.
- Used TG298 thermal camera: if you're comparing thermal patterns rather than making safety-critical decisions, a verified used unit can be a smart buy.
- Extech pH meter: new or used, calibrate it yourself before every important use. That's non-negotiable.
No brand deserves to be bought on autopilot—including Renishaw. But “cheaper” is not the same as “best value.” You have to know your uncertainty budget before you know your supplier strategy.
After we approved the new Renishaw order, I kept second-guessing the spend. We could have saved a few thousand dollars—and I was ready to hear about it from finance. I didn't relax until the first CMM run came back with the probe and encoder performing exactly to spec. The two weeks of waiting were stressful. The confidence stayed.
