I am designing a mounting plate for a few servos using ponoko. These will be HS-422 servos, and I cannot find some crucial information about these. First of all, there are no mounting hole diameters listed anywhere. Does anyone know these? Also, the location of the servo “shaft” is the important thing for me. Why isn’t the shaft location on the datasheet at all?? Does anyone know this inormation? I’ve tried googling, but with no luck.
Thank you!
Justin W
Welcome to the world of hobby robotics. lol
You can sit down with a pen, paper and a caliper and figure it out. I have found generally that the output shaft is usually set-in from the end about half the thickness of the servo. Beyond that every one is slightly different. Try making brackets that fit a range of servos! lol
Try searching. There are some dimensions out there. Often contradictory! Just yesterday I was able to find good data on a Parallax (Futaba) continuous rotation servo:
parallax.com/Portals/0/Downloads/docs/prod/motors/ServoDimensions.pdf
It fits the ASB-13B bracket, as does the HS-422, so you might be able to use the data. A few critical measurements should verify that.
Less then a minute of searching found this data sheet:
usna.edu/EE/ee411/EE411RobotProject/Motor%20hs422.pdf
Alan KM6VV
Alan he has that data sheet, just like we do.
lynxmotion.com/images/data/hs422.pdf
He’s complaining that the measurements he needs are not on the data sheet…
Jim,
The Parallax PDF has a shaft offset dimension, as well as the mounting hole dimension. Different servo, but should be close. 10.4mm from the case edge.
The hole-to-hole dimension is probably more demanding, and I’ve seen it vary in documentation as well. but luckily (?), the mounting holes in the tabs are rather sloppy, to allow for adjustment. the mounting holes are also (I believe) designed to take flexible mounting, i.e., some sort of rubber bushing.
Actually, I’d be more inclined to reference the shaft centerline from the center between the two mounting holes. Makes it a little easier to ignore body size differences…
Alan KM6VV
Hi Jonny,
Thanks for verifying that.
Alan KM6VV
The holes size was initially designed to accept these push in fasteners.
These are great for quickly building assemblies that do not require a lot of rigidity. But the larger holes do make it possible to properly align all the different servos. Zenta also uses a larger screw, maybe 4mm? and it fits the holes much better. It’s all about versatility.
If I’m going to mount the R/C servo on a plate, then I like to tap the plate 4-40, and use a SHCS with a washer.
Perhaps if we could see a pix of the intended mounting, we could suggest more…
Alan KM6VV
Servo are RC stuff at the base…
And they, most of the time, need damping, that’s why they have big hole.
Just to mount those damper
I do use bigger screw on mine and only 2 is needed (for me).
no need for dampeners on a robot, at least untill you put a engine or motor on it … or something else powerfull and vibrating 
LOL… i know
was just an explanation 
Not too keen on the push-in plastic fasteners; I’d like to be able to locate the R/C servos a little more accurately. SHCS and a washer on a 4-40 thread work well. And I’m thinking about going over my hexapod and replacing the 3mm hardware with these, and a integral star-washer nut.
There is vibration, at least on a walking 'bot. I’ve wound up loosing a nut here and there after each demo at a club meeting. The new nuts should fix that!
I’ll bet we could find 3mm (I think that’s the size) integral star-washer nuts if we looked!
Alan KM6VV
