After calibrating the servo (finding the center point) with the SSC-32 and finding the offset, say:
Ideal PWM Center = 1500
Actual PWM Center = 1430
How far off does the PWM have to be from the “Ideal” 1500 to warrant the removal of the servo horn to mechanically re-center it onto the spline???
pretty sure the hitec splines are 15 degrees so, unless it is too early and I need caffine, that any more then +/-7.5 degrees can be improved upon by re-positioning the horn on the output shaft.
Yes that’s it. The spline has 24 teeth, so 360 / 24 = 15° I have always liked that about the servos spline. 8)
Another way to look at it is the offset is +/- 100uS. So if the software offset can’t fix the physical offset you must remove and reposition the horn on the spline.
Thanks guys!!! I think I need to take a phillips screwdriver to a couple of them…
You don’t necessarily have to take everything apart!
After you unscrew the servo horn screw, you can often just pull the servo horn off of the splined shaft, rotate it a spline, and push it back on.
Alan KM6VV
Thanks Alan, that’s what I was referring to, the Phillips to take the horns off…
Is it recommended to put some thread lock compound on the “self-tapping” screw that keeps the horns onto the spline?
I noticed that several of my servo horns worked its way loose from continued use (and abuse) on my hexapod…
I haven’t heard any one say that thread-lock is needed on the servo horn screw. Most seem to be self tapping. On the real threaded servo horns it might be effective.
I’m wondering why lock washers aren’t used on all the little 2-56 attachment screws! I’m switching to allen head cap screws (button head) to hold stuff together better.
Alan KM6VV
If you find that your screws are backing out then blue loctite would probably be all you need. I would stay away from loctite if you can avoid it because it can really make removing screws a chore. I don’t have any problems with my screws backing off, probably because the horns have a nice tight fit over the splined servo shaft.
If there’s a need, use it. I would not use loctite on screws that don’t back out. If you have to use some, use a small amount. It might even be best to use a toothpick to apply it.
I have never seen a servo horn screw back out on a hexapod, ever, um, well except the Phoenix! lol Yes, it’s a good idea to use some locktite on the servo horn screw on the vertical servos. A little bit will do it.
There shouldn’t be a need to have tiny lock washers on the 2-56 hardware.
