Why I Refuse to Buy Lovejoy Couplings From a Supplier That Hides Dimensions

I have a rule after five years of managing purchasing for a 145-person manufacturing company: if a supplier hides dimensions, tolerances, or pricing, they're hiding more than data. They're hiding risk. I place 60-80 orders a year across a couple dozen vendors, and I've been burned enough times to demand full transparency before I issue a PO.

That rule came from a costly lesson in 2023. I ordered what I thought was a direct-replacement Lovejoy coupling from a supplier who listed a great price but no dimension sheet. The bore was wrong for our shaft. The supplier's response? "We can't verify application fit." We lost two days of production, and I had to explain an $1,800 expedite fee to my VP. Not fun.

So yes, I have an explicit opinion: if you can't provide complete technical data and clear pricing upfront, you don't deserve the order. Period.

The L110 and L190 Dimension Problem

The clearest example came during our 2024 vendor consolidation project. Our production lines use jaw-type Lovejoy couplings in several sizes, but the two that come up most are the L110 and L190. These are common, documented, standard products. Their dimensions aren't a trade secret—they're published in Lovejoy's own catalog. But you wouldn't know it from how some suppliers behave.

I needed the L110 Lovejoy coupling dimensions to verify bore compatibility with a 1-1/8" shaft on a conveyor gearbox. The L190 dimensions came up a week later when we were checking a different line for a 2-3/8" shaft application.

Two of our existing vendors made me jump through hoops. One said "I'll have our engineer call you back." The other said they'd email a quote with dimensions attached—if we signed a nondisclosure. For a standard jaw coupling. I'm not making that up.

The third vendor had both dimension sheets published on their website. The L110 Lovejoy coupling dimensions covered bore range, outside diameter, length through bore, and set screw placement. The L190 Lovejoy coupling dimensions showed the larger body size, the bigger bore capacity, and hub spacing. All of it visible before I even created an account.

That same vendor listed pricing online too. Not "call for quote." Actual numbers. To be fair, they weren't the lowest quote—but their quote was the final number. No surprise setup fee at invoicing. No "we assumed you wanted the hardened hub" upsell. That's the thing nobody tells you about "cheaper" suppliers: the initial quote is just the opening chapter.

Why does this matter? Because every layer of friction a supplier adds between you and basic specs is a sales funnel, not engineering protection. They want you on the phone so they can steer you toward higher-margin options. When a vendor publishes dimensions and pricing openly, they're saying: "We want you to make the right choice." I sent them the PO the same afternoon. It took me longer to figure out which supplier was being obstructive than it took to make the purchase.

Small Motors, Big Transparency Gap

Now for a different example. Our engineering team was building a proof-of-concept for an automated alignment fixture. They asked for a 28BYJ-48 stepper motor—a small 5V stepper motor that's common in prototyping. These cost a few dollars each, so you'd think the purchase process is simple. It should be.

One supplier listed the 28BYJ-48 stepper motor with no wiring diagram and no gear reduction ratio. When I asked about the step angle, the order taker had no idea. Is it the 5.625° step angle with 64:1 reduction—4096 steps per revolution? Or the less common 1/16 version? They couldn't tell me. The price was cheap, but the information vacuum made it worthless.

The supplier we chose had the full spec sheet online: step angle, gear ratio, coil resistance, wire colors, torque curve. The motor cost $2 more. I spent zero extra time chasing specs. That's a faster, safer purchase, full stop.

The same pattern shows up with brushless DC motors, and the stakes are bigger. When we were upgrading a conveyor system, we needed a brushless DC motor to replace an aging brushed unit. One vendor advertised "retrofit compatible with existing motor mounts." That's a nice phrase, but it doesn't mean anything without mechanical dimensions and a torque-speed curve. Brushless DC motors have very different torque profiles than brushed motors. Skip that curve and you're buying a surprise.

The vendor we trusted published the motor's performance curve, drive requirements, and thermal limits in a single PDF. It didn't just make our decision easier—it protected us from a bad retrofit and a second round of downtime.

Honestly, I've never fully understood why some vendors put barriers around basic specs. I'm not asking for their winding algorithms. I'm asking for the same information that's on the manufacturer's datasheet. Suppliers who share it treat me like a partner. The ones who don't treat me like an upsell target.

How VFD Controls Motor Speed (and Why Education Is Transparency)

There's another layer of transparency beyond datasheets: education. Last year, our maintenance team needed a variable frequency drive for a 5 HP conveyor motor. Everyone had a rough idea of what a VFD does, but when I asked around, nobody could explain how a VFD controls motor speed. Our maintenance lead shrugged and said, "magic boxes, right?" (He was joking. Mostly.)

I started researching and reached out to two drive suppliers. The first said, "Just tell us the motor HP and voltage. We'll send you a package deal." Every cost analysis pointed to that budget option. Something felt off about their non-answer. Turns out "we'll send you a package deal" was a preview of "call us when it doesn't work."

The second supplier sent a short, plain-English guide. It explained that a VFD controls motor speed by varying the frequency of the AC power supplied to the motor, while also adjusting voltage to maintain a constant V/f ratio. The drive doesn't brake the motor slower; it changes the frequency of the power feeding it. The guide also covered constant torque versus variable torque applications, which matters for conveyor loads.

That guide changed the conversation between purchasing and maintenance. Our team could finally speak up in review meetings about what we actually needed. And yes, the supplier got the order, even though their quote was slightly higher.

Maybe education feels like a soft factor. But from a purchasing standpoint, a vendor who explains how a VFD controls motor speed is a vendor who's confident in their product and cares whether you apply it correctly. That reduces my risk of a failed installation, a callback, and a chargeback. That has real dollar value.

The "Cheapest Quote" Trap

I know what some buyers are thinking: "I just need the lowest price, especially in a budget year." To be fair, I've ordered from low-price vendors plenty of times. In 2022, a cheap coupling supplier couldn't provide proper documentation—no material cert, no test report—and our quality team rejected the entire lot. That cost us $2,400 in expedited replacement costs. The initial savings vanished, along with my patience.

And to the objection that "suppliers have a right to protect proprietary information": I agree, to some extent. But there's a difference between proprietary design and the standard dimensions of a catalog product. L110 and L190 couplings aren't a secret. The 28BYJ-48 stepper motor's gear ratio isn't a secret. A brushless DC motor's torque curve—provided by the original motor manufacturer—isn't a secret. When a supplier obscures basic datasheet information, they're not protecting trade secrets. They're protecting a sales process that relies on control.

The real question isn't whether you can find the cheapest price. It's whether the supplier makes it easier or harder for you to buy correctly. That's the metric that actually impacts your bottom line.

My Rule, Unchanged

So here's my position, and I'll state it without hedging: I will always prefer a supplier who publishes dimensions, documentation, and pricing upfront over one who hides them behind phone calls and emails—even if the transparent vendor's quote is higher.

Transparency isn't a luxury. It's a baseline. Suppliers who share complete technical information about Lovejoy couplings, motors, and drives are the ones who want a long-term relationship. The vendors who force a phone call before showing basic specs are the ones who've learned that obscurity sells better than honesty.

If you're buying couplings or motors, here's my advice: ask for the L110 and L190 dimension sheets, the 28BYJ-48 wiring diagram, the brushless DC motor torque curve, and someone who can explain how a VFD controls motor speed. If they can't deliver all of that without a fight, find another supplier. I did, and it made my job considerably easier.

This was accurate as of Q1 2025. Product specs and market conditions change, so verify current details before placing an order. But the principle that transparency builds trust? That doesn't change.