Every maintenance engineer eventually faces the same call: a Thomson linear actuator fails on a critical line, and the repair quote arrives at $900. A new one costs $2,400. The shop says five days; the factory says ten. Which do you choose?
I've been handling replacement and repair orders for motion control components for seven years at a packaging plant in New Hampshire. I've personally made—and documented—four significant mistakes in that time, totaling roughly $8,000 in wasted budget. This article is the comparison framework I built after those mistakes, so you can avoid repeating them.
We're comparing two paths when a motion component fails:
- Repair: sending the failed unit to a qualified shop, like a Fanuc servo motor repair job or a rebuilt actuator.
- Replacement: ordering new components from the manufacturer, like a Thomson linear actuator or parts listed in the Thomson linear bearings catalog.
I'll compare them across four dimensions: lead time, total cost, reliability, and electrical compatibility. Each one has burned me at least once.
Dimension 1: Lead Time—Certainty Beats Speed
In September 2024, our carton feeder went down. The Thomson linear actuator on the conveyor had stripped its ball screw. Two options sat on the table:
- Repair: local shop quoted five business days; $700 in labor plus parts.
- Replace: Thomson's site showed 7–10 business days for the standard actuator; $2,400.
The repair was faster and cheaper on paper. I went with it. Actually, I didn't just go with it—I approved it on a Tuesday morning and told the production manager we'd be running by the weekend. The actuator came back on day six, and it ran for four hours before failing again.
The shop had used a non-standard ball screw that didn't match the original specs. To fix it, they had to source replacement parts from a local New Hampshire ball bearing distributor. That added four more days. The "five-day repair" turned into a 12-day ordeal that cost us an extra week of production downtime.
Here's what I learned: a repair quote covers bench time, not supply chain time. If the shop has to order parts, you're waiting on their vendors. Meanwhile, when you order new, the lead time is published and predictable. You might not like waiting ten days, but you can plan around it.
And honestly, a predictable ten days is worth more than a "maybe five" that turns into twelve. When the line is down, certainty is the product. That's why we paid $180 for expedited delivery on the eventual replacement—the fee bought us a guaranteed arrival date, and that date was worth far more than the shipping cost.
One thing that helps: search 'thomson-linear' in your procurement system. You'll see which parts are still active, what the current lead times are, and what replacement costs. That data should anchor the decision, not the repair shop's optimistic estimate.
Dimension 2: Total Cost—The $1,480 Savings That Cost $7,980
I went back and forth between the repair and the replacement for two days. The repair made sense on paper. My gut said the new actuator was the safer move. I chose the spreadsheet, and the spreadsheet lied.
The repair cost $920 total. The new actuator would have been $2,400. I saved $1,480 by repairing. Except the repair failed after four hours, and the final tally looked like this:
- $920 for the first repair that failed
- $180 for expedited shipping on the replacement
- $2,400 for the new actuator
- Roughly $4,300 in lost production from the extra downtime
Total: about $7,980. The "smart" repair decision cost us nearly three times the replacement price.
To be fair, I've seen repairs go right. In 2019, a Fanuc servo motor repair quote came in at $650 versus $2,100 for a new servo motor. The shop did an excellent job, and that motor ran for four more years. So the cost comparison isn't "repair always loses." It's that repair carries a failure risk—and when that risk comes due, you pay for the repair, the replacement, and the downtime.
That's the risk adjustment most cost comparisons miss. If the repair works, you save 40–60%. If it fails, you pay double. You're not comparing two prices; you're comparing a sure thing to a lottery ticket.
Dimension 3: Reliability—The Parts Lottery
A repaired component is only as good as the parts the shop puts into it. In 2022, a different shop sent an actuator back looking immaculate. The tech had replaced the bearings with what he called "equivalent" parts. Three weeks later, the actuator started grinding. We pulled it apart and found the bearing cage had collapsed.
I'm not a metallurgist, so I can't speak to the material composition of that bearing cage. What I can tell you from a maintenance perspective is this: a new Thomson linear actuator comes with factory tolerances, original engineering specs, and a warranty. A repaired unit comes with the shop's word.
Before you approve any repair, ask two questions: Are you using OEM-grade parts? And what's your documented failure rate on this component type? If the shop can't answer both, you're gambling.
Oh, and check the catalog. If your actuator model is still listed in the Thomson linear bearings catalog, replacement is straightforward. If it's discontinued, you're suddenly in "repair or retrofit" territory, and the whole decision changes.
Dimension 4: Electrical Compatibility—The Hidden Trap
Here's the dimension that surprised me. In June 2023, a Fanuc servo motor repair came back from the shop, and our electrician asked: "What size VFD for a 5HP motor do we need here?"
I didn't know. The existing drive had been sized years ago, and nobody had documented the reasoning. The motor nameplate showed 5HP with a full-load amperage around 7.6A. Our contractor explained that you size a VFD to the motor's FLA, not just the horsepower—and that many engineers oversize to a 5.5kW drive for headroom.
But the real trap: a repaired motor can draw more current than the original. Rewound coils, slightly different tolerances, a bearing with extra drag—it adds up. If the VFD was sized close to the original motor's FLA, the repaired motor can push it into overload.
A repaired motor may draw more than its nameplate FLA. Verify the actual current draw before reinstalling it on an existing drive.
This is electrical engineering territory, which isn't my expertise. I'd recommend consulting a qualified electrician before reinstalling any repaired motor into an existing system. What I can tell you from a maintenance perspective is: verify the current draw after repair, and budget for a larger VFD if the numbers come back high.
We didn't verify, and we lost a $1,200 VFD plus three days of production. The repair itself was fine. The electrical integration wiped out the savings.
So: Repair or Replace? Here's the Checklist
I've maintained this checklist for our team since Q3 2023, and it has caught 12 potential errors in the past 18 months. It's not complex, but it forces the right questions:
Choose repair when:
- The component is out of production and no new equivalent exists
- The shop uses documented OEM-grade parts and offers a warranty
- Downtime is not critical—you have a spare or can manage the load
- The quote includes a fixed delivery date, not a "best effort" promise
Choose replacement when:
- The part is still in the manufacturer's catalog (check the Thomson linear bearings catalog or equivalent)
- Your line is down and production loss exceeds the cost difference
- The component has already failed once—especially on a critical axis
- Electrical integration is uncertain (servo motors, VFDs, drives)
Looking back, I should have ordered the new actuator the moment the September 2024 repair quote arrived. At the time, I told myself: "what are the odds the repair fails? This shop has never burned us before." The odds caught up with me.
This was accurate as of January 2025. Thomson's lead times shift with demand, shops change, and the market evolves. Verify current availability and pricing before you commit.
If you've ever watched a line stay dark for an extra week because a "cheaper" repair failed, you know the feeling. Take it from someone who lost $8,000 to this exact decision: when the line is down, the certainty of a new component is worth the premium. Not because repair is always bad—but because in an emergency, "probably fine" is the biggest risk in the room.