Do you it is possible to build this arm with 422’s and that it will be able at least to pick up… like sometyhing very small and light? When I have the money I will buy a tracked vehicle when it comes out and I would like to put an arm on it, if I have extra money I will buy some 5645’s…
thx, Sam
It depends on how many degress of freedom you want. A small SES arm might work, but anything with 5 (probably 4) or more degress of freedom is going to give you trouble on the shoulder servos for sure. You might be able to get away with 5645s on the higher stress joints near the base and 422s on the lower stress ones along with some balancing springs.
Yea, that isn’t going to work. It’s a 5 degree of freedom arm and too big. I’ve already talked to someone else on the forum who tried and didn’t have much sucess with 422s (though he also had power issues). I suggest using a shorter arm, or getting better servos.
Think more like this:
yeah, that was my other possibility… well it’ll have to do 
Im amagine the arm without the shoulder or elbow servos. Thats what I have sticking out of the front of my rover and it works great! I used 645’s and a load balancing spring for more lifting capacity though the gripper is limited and wont pick up any real wide things. Also, I just attached it by 1 screw throuhg the center whole of the C bracket and a spacer in between to protect the lexan. Works great, but the screw has to be super tight so it dosent slide side to side. Im sure if you drilled two smaller holes in the C bracket, ud be fine. 8)
you have to wonder if the shoulder/base of that will be strong enough with a single 422. you could use an ASB-13 and 2nd servo but I think the question then will be if it’s possible to adjust two analog servos to work well in parallel. a third option might be to just make that one servo a 645 and use 422 for all the rest.
I originally had the whole arm, but your right the servos on the shoulder and elbow were terrible and couldn’t hold up the wieght. When using them, it either could not lift itself up or it was really jerky and bouncy, so I took them off. It was a bit too big for the robot anyway. The other issue was for some reason, it did not work well with the lynx 5 software or ps2 controller?? kinda wierd but I think it manly had to do with the size differences.
I now have the 3DOF arm working with the Lynx 5 software with no modifications to it. The DOF that are connected work great with the software and havent given me a problem anymore.
Can you show me the conficuration of the arm please? or a picture?
Thanks
Sam
np, ill have it uploaded by this afternoon.
ok cool thanks man
Sorry about the pictures, I spent all day looking for my camera and came up with zilch. anyways, heres something very similar to my setup:
lynxmotion.com/images/html/build063.htm
The only difference is that I used the middle whole with a spacer in between becuase there was an existing hole there for a bracket. I also put a load bearing spring on the C bracket to the Top servo for better power and to hold the arm up while Im driving with the servos turned off.
Hope this helps, just PM me for details.
I don’t think it will work. As an example, I have a custom pan/tilt turret on W.A.L.T.E.R. which currently uses 2 HS-422 servos. The tilt servo can’t hold its position to keep the two sensors steady. All I have the tilt servo supporting is an ASB-10 and a 3" U channel with two sensors attached. I thought a 422 would be able to lift this and keep it steady, but apparently it won’t.
I’m going to change out the 422s for 475s which should be adequate for what I need, even after I add the 3rd DOF. This addition will create a sensor arm which will allow the sensors to be pointed up and down over the side of the bot. It will also allow some other interesting things to be done such as periscoping (3DOF required) and peeking around corners (with a 4th DOF).
Given my results, I wouldn’t recommend using 422s for any arm. Go with 475s as a minumum for arms.
8-Dale
Yupyup, I tried building that exact arm, but cheaped out on the servos. Everyone learns this the hard way once. The 422 in the elbow of that arm cant even lift whats attached to it. The pair of them in the shoulder just laugh at me when I try to command them. Hoping to upgrade it one of these months 
