I'm looking for what might best be described as a hybrid servo horn/clevis. What I need is basically a one-armed servo horn, but with a 2nd, parallel arm, spaced at about 3/32" from the first. This would form what amounts to a clevis that attaches to a hobby servo's output gear. It needs to be pretty strong, & I've considered making my own out of a pair of existing horns, but I'm not sure that'll be strong enough.
Any ideas?
JM
Thanks, but can you be a little more specific? I've looked all over ServoCity & can't find what I'm looking for. Here's a drawing, if that helps:
I figured that's what you're trying to do. I don't recall seeing one ready-made (doesn't mean they don't exist), but I don't see why it couldn't be made. To test my theory I tried one with standard nylon horns, and did it in a couple of minutes.
On one arm I enlarged the screw hole to the same size as the spline shaft. I just routed it out with a drill and used a rate-tail file for touch up. That horn goes onto the servo upside-down.
I then filed off the servo shaft socket on the other to almost flush with the face of the horn. That sandwiches over the bottom horn. I was able to use the regular servo horn screw but depending on the horns you use, and the length of the supplied screw, you might need a slightly longer one.
You *might* need a small shim -- a #2 or #3 washter or something -- placed over the servo shaft, as a spacer. Otherwise, the arm may sit too low and rub against the servo since there is no longer the usual clearance that a regular servo horn provides.
This double-horn seemed as strong, or stronger, than what someone would make, unless it's custom-machined out of aluminum.
-- Gordon
That may end up working just fine! Perhaps if I file down the "shaft socket" area of one or both...
Thanks for the good idea! I'll give it a try.
JM
I reread my message and all of its typos, and just wanted to add one thing: I tried adding a series of #3 flat washers into the bottom (drilled-out) horn, and that did indeed prevent the bottom horn from scraping against the body of the servo. A stack of three of them added just enough thickness to keep the horns a fraction of a millimeter away. You might find you need something similar.
-- Gordon
Typos & all, I got the idea. I may or may not need the extra spacing. Simple & head-slappingly obvious, once it's pointed out, like many great ideas! I may do my own slightly differently, shortening the hubs on a pair of horns to get the spacing I need.
Thanks!
JM
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.