8 Real Questions About Boston Gear & Motion Control (With Mistakes I Made So You Don't Have To)

Look, I've been working with motion control components for years. Specifically, I handle orders for transmission parts and motion control systems. In that time, I've personally made (and documented) 14 significant mistakes, totaling roughly $9,200 in wasted budget. Now I maintain our team's checklist to prevent others from repeating my errors.

This FAQ covers the questions I get asked most often—plus a few I wish people asked before making costly mistakes.

1. What size VFD do I need for a 5HP motor?

A 5HP motor running at full load draws roughly 13.6–14 amps at 230V (3-phase). The rule of thumb: size the VFD for the motor's full-load amps (FLA), not the motor's horsepower.

Here's a mistake I made in 2021: I spec'd a 5HP VFD for a 5HP motor. Worked fine—until the motor saw a brief overload. The VFD tripped. Cost us $890 in redo and a 1-week delay.

What I learned: Size up one step. For a 5HP motor, use a 7.5HP VFD. It handles the inrush and minor overloads without tripping. The incremental cost is negligible compared to downtime.

Reference: NEMA standards recommend VFD sizing at 110-125% of motor FLA for most applications. Your local utility's motor efficiency data may also affect this calculation.

Not ideal, but workable: a 5HP VFD with a 150% overload rating. Better than nothing.

2. Why is "Boston Gear" so much more expensive than generic options?

Seriously, I hear this every week. It's tempting to think you can just compare unit prices and go with the cheapest. But identical-looking specs from different vendors can result in wildly different outcomes.

The 'lowest price' advice ignores three things: application engineering support, inventory availability, and—critically—product consistency. On a 200-piece order of spur gears where every single item had to match dimensions within 0.005", we caught three errors from the generic supplier. Boston Gear batch? Zero errors across 700+ pieces.

If I could redo that decision, I'd invest in better specifications upfront. But given what I knew then—nothing about the vendor's interpretation quirks—my choice was reasonable.

Will you pay more with Boston Gear? Yes. Will you save on rework, delays, and headaches? Also yes.

3. Why is my servo motor jittering with an Arduino?

A classic. In my first year handling orders (2017), a client called panicked. They'd wired a Boston Gear servo motor to an Arduino Mega and the motor jittered uncontrollably. They thought the motor was defective.

Here's what you need to know: Servo motors need a stable PWM signal. Arduino's built-in analogWrite() at 490Hz works, but the timing jitter from USB power or heavy CPU load can cause micro-delays. Result? Jitter.

• Step 1: Use a separate 5V power supply for the servo. No, the Arduino's 5V pin can't handle 2+ amps.
• Step 2: Use an external servo driver board (like the PCA9685). It offloads the PWM generation from the Arduino.
• Step 3: Check your torque requirements. A mismatch between motor torque and load = oscillation.

Three things: stable power. dedicated PWM. matched torque. In that order.

4. What's the difference between a fuse reducer and a fuse block?

More importantly: can you substitute one for the other?

In 2022, someone on my team used a fuse reducer as a fuse block. The reducer sat loose, arced, and fried the panel. $450 wasted + credibility damaged. Lesson learned: know the physical difference.

Use a fuse reducer inside a fuse block when you change fuse types. Never as a replacement.

5. How do I choose between worm gears and spur gears for my application?

It's tempting to think spur gears are always better—they're more efficient, right? But the 'spur gears for everything' advice ignores noise, load angle, and shock tolerance.

I once ordered 350 worm gears for a conveyor system that ran 24/7. Checked the specs myself, approved it, processed it. We caught the error when the first unit showed up six weeks later. The application needed spur gears because it required 200% reverse-drivable torque. Worm gears lock under load. $3,200 order, straight to surplus.

Here's a quick guide:

• Worm gears: High reduction in one stage, quiet, non-backdrivable (safety). Great for elevators, hoists, and angled drives.
• Spur gears: Higher efficiency (95-99% vs 50-90% for worm), backdrivable, simpler to mount. Best for parallel shaft applications without noise concerns.

Worse than expected: the 3-day production delay while we sourced replacements.

6. Can I use a stepper motor where I need a servo motor?

Short answer: yes, if you're okay with lost steps and vibration. The 'stepper is always cheaper' advice ignores position feedback.

Looking back, I should have spec'd a closed-loop servo from the start. At the time, the stepper motor seemed like a good budget option. It wasn't. The vibration caused visible banding on the product, and we got three rejections before upgrading. We've caught 47 potential errors using our pre-check list in the past 18 months—this scenario is #1 on that list.

If your application needs position confirmation (like a pick-and-place robot), use a servo motor with an encoder. If it's open-loop and doesn't care about missed steps, a stepper works fine.

7. What size linear actuator do I need for a 50-pound load?

You'd be surprised how many people ask this after buying. Here's the answer: size for 2x your static load minimum, 3x for dynamic loads.

I once saw a $700 actuator fail on a 45-pound load because the spec sheet said "50lb capacity" but didn't mention duty cycle. The actuator ran for 10 seconds, then rested 50 seconds. The customer ran it with 10 seconds on, 10 seconds off. Burned out in 12 hours.

The hidden cost: $150 in rush shipping + $250 in lost production time. That should have been avoided with a 100lb-rated actuator at $900.

Three things: load rating. duty cycle. stroke length. In that order.

8. Where can I find "knock-off" Boston Bruins gear for my hockey team?

Look, I deal with mechanical gear, not hockey gear. But this question comes up so often I've learned to distinguish the two. If you're searching for ski gear Boston or knock-off Boston Bruins gear, you're in the wrong place.

For actual transmission components under the Boston Gear brand, here's what you need: their online catalog PDF (700+ series) lists every part number and dimension. Download it. Compare it. Then call a distributor. The catalog is free; the mistake of buying unlisted knock-off components is not.

Trust me on this one: the 'compatible but cheaper' parts for mechanical gear are rarely compatible with real specs. I've seen it cost people way more than the savings.

Pricing note: Boston Gear pricing varies by distributor. In 2025, expect 20-40% premium over generic alternatives for precision-ground components. Budget accordingly.