Servo Horns (Bruce Bates question)
Archiver
Posts: 46,084
Bruce-
I never saw a response to your request regarding dimensions on "standard"
servo horns. I don't know if there are standards across all brands, but here
are some dimensions for the Futaba and compatible (e.g. Tower Hobbies)
large-scale servos. It appears from my box of "parts" that the servo horn
dimensions are directly related to the ounce-inches of torque of the servo:
the greater the torque, the larger the span on the servo horn.
The figures below were measured hole-to-hole. Many of the servo horns have
multiple holes that allow for span reduction (figures below are the maximum
span). Some of the holes are spaced 3/32" apart (smaller horns), while others
are 3/16" apart (larger horns).
"X" - 1 5/16" and 2 1/8"
double "X" (6 arms) - 1 1/16"
circle - 1 9/16", 1 5/16" and 9/16"
single arm, across both sides - 2"
single arm, one side only - ¾", 1 ¼", and 1 11/16"
All in all, it looks like a mixed bag to me. I think that I get a different
set of horns for each torque size servo that I buy.
Just for your information, I use the servos to move metering plates on
handheld equipment used to dispense good "bugs" for agriculture. I use the
STAMP to activate the servo to move the metering plate on command from a
momentary switch.
I don't know if I helped, and maybe someone else has better information.
Could Tower Hobbies (or Futaba, etc.) provide such information?
All the best to you, Warren Sargent
I never saw a response to your request regarding dimensions on "standard"
servo horns. I don't know if there are standards across all brands, but here
are some dimensions for the Futaba and compatible (e.g. Tower Hobbies)
large-scale servos. It appears from my box of "parts" that the servo horn
dimensions are directly related to the ounce-inches of torque of the servo:
the greater the torque, the larger the span on the servo horn.
The figures below were measured hole-to-hole. Many of the servo horns have
multiple holes that allow for span reduction (figures below are the maximum
span). Some of the holes are spaced 3/32" apart (smaller horns), while others
are 3/16" apart (larger horns).
"X" - 1 5/16" and 2 1/8"
double "X" (6 arms) - 1 1/16"
circle - 1 9/16", 1 5/16" and 9/16"
single arm, across both sides - 2"
single arm, one side only - ¾", 1 ¼", and 1 11/16"
All in all, it looks like a mixed bag to me. I think that I get a different
set of horns for each torque size servo that I buy.
Just for your information, I use the servos to move metering plates on
handheld equipment used to dispense good "bugs" for agriculture. I use the
STAMP to activate the servo to move the metering plate on command from a
momentary switch.
I don't know if I helped, and maybe someone else has better information.
Could Tower Hobbies (or Futaba, etc.) provide such information?
All the best to you, Warren Sargent
Comments
>Bruce-
>
>I never saw a response to your request regarding dimensions on "standard"
>servo horns. I don't know if there are standards across all brands, but here
>are some dimensions for the Futaba and compatible (e.g. Tower Hobbies)
>large-scale servos. It appears from my box of "parts" that the servo horn
>dimensions are directly related to the ounce-inches of torque of the servo:
>the greater the torque, the larger the span on the servo horn.
>
>The figures below were measured hole-to-hole. Many of the servo horns have
>multiple holes that allow for span reduction (figures below are the maximum
>span). Some of the holes are spaced 3/32" apart (smaller horns), while others
>are 3/16" apart (larger horns).
>
> "X" - 1 5/16" and 2 1/8"
>double "X" (6 arms) - 1 1/16"
>circle - 1 9/16", 1 5/16" and 9/16"
>single arm, across both sides - 2"
>single arm, one side only - ¾", 1 ¼", and 1 11/16"
>
>All in all, it looks like a mixed bag to me. I think that I get a different
>set of horns for each torque size servo that I buy.
<snip>
Thanks Warren
Regards,
Bruce