Servo comparison

ya got me. The specs are the same on both of them as far as I can see. They both have 44 oz. of torque. both are ball bearing. both have a transit time of .23 sec! However, at the Tower web site, the 3001 is $19.99 and the 3004 is only $13.49? Anyone?

What is the difference between the Futaba S3001 servo and the S3004 servo?

Thanks ======================================== The 3001 is considered a 'precision' BB servo, where the 3004 is a 'standard' BB servo. The 3001 has an oilite bushing in addition to the bearing. I've never been inside a servo but I assume the bushing is at the bottom of the shaft. The 3001 weighs 1.6 ounces where the 3004 weighs 1.3. I'd guess the bushing helps reduce wear at the bottom of the shaft and makes it maintain adjustment better over time.

I don't have either of those servos to open up, but . . .

If you surf to

and note the terms "Top/Oilite" in the bearing column for the S3001, and "Top" in the bearing column for the S3004, it's gotta mean something.

I'd bet the 3001 output shaft has a top ball bearing and a lower oilite bushing, and the 3004 output shaft has a top ball bearing while the lower end of the shaft runs in the case itself.

You can also get a sense of Futaba's use of bearing terms if you look at the servo application chart on the same site. Some servos are listed as "1BB/1MB" meaning a top ball bearing and a bottom oilite bushing, "1BB" meaning a top ball bearing only, and "-" meaning no bearings at all (the shaft runs in the case itself - the bottom line servos). Cheers, Fred McClellan the dash plumber at mindspring dot com