Going thru some hardware I came across a box of 7/8" roofing nails. This type of nail has a large flat head to keep the head from pulling thru the roofing. Doing some tinkering, this type of nail could be used to supply load support on the servo side opposite to the servo horn. I think there are ball bearings sets and such sold to do this for heavy loads, but for lighter loads, just a hard point pin might be of use. The nail shaft is ~1/8" in diameter. For this test setup, I used hot glue to attach the nail to the servo, which is easy to remove when desired. Epoxy would make for a stronger perminate attachment if required. The nail shaft could be trimed to a shorter desired length.
So, I actually bought a HRS5995TG case set to see if I could use the bottom cover (the one with the built in axial mount) on a 475 or 645. No such luck. Looks like I will be doing something like this soon.
The hot glue is surprisingly strong as the nail is still tightly attached after a year and a half. Cut the nail to a short length with a dremel tool cutoff disk where the shaft length is just long enough to have the brace and a small washer keeper on the shaft with a small drop of glue behind the washer to keep it on the nail shaft. Another approach where arm is a fixed width and not easily spread over the width of the servo would be to use a very small nut and bolt to make a brace mount where the bolt can be removed. Put the bolt thru the arm hole and run the nut down on the bolt on the opposite side until the slack is out but the bolt still freely rotates in the arm hole. Cut the excess bolt length off flush with the back of the nut. Disassemble, and with the bolt threaded in the nut with the bolt shaft flush with the rear of the nut, hot glue the rear of the nut to the servo. When the glue cools, remove the bolt and then install the arm and reinsert the bolt. Something easy and quick to try if one has a dremel tool.
Somebody say hot glue? Below is a quick setup I previously described using a nut/screw setup to make a hot glued back side servo horn piviot point. The #8-32 x 3/8" nut/screw eight pack was $1 at Home Depot. Putting some force on the nut/screw, it isn’t going to be broken lose by force generated by just a servo alone. Quick and inexpensive to “get’er done”. Get longer length screws than I did if doing this so they will be much easier to hold when working with them.
I used to use hot glue for stuff all the time. But then I realized when you try to take it off something…lets just say it’s a bit messy and a big pain to remove.
Did a quick stress test on the hot glued nut/screw combo and it successfully supported 10 lb in both shear and tensile loading. Plenty strong enough for hex bot use.
I agree about the looks thing. If I had $1,200+ in a bot, I’d pay the extra $$$ to make it look good. On the other hand if I only have $12 in a project or just doing some testing, then I doubt I’d spend the extra $$$.
