Deadly servo breakage epidemic!

Help & Support Robot Parts
1

I am building a sort of snake type robot and i invested in cheap GWS servos (s03t). I bought 10, and had to order replacements as they started dying one by one. now 4 of them have shredded gears :angry: !
(i also fried one with a dumb mistake). anyways, i am giving up on these servos, and i am wondering if anyone has any suggestions for what i can use instead. I am on a low budget so they should be cheap, yet somewhere around the specs of the S03t (i liked them other than the fact that they kill themselves :angry: ). so somewhere around 100 oz-in. also, i am in Canada so if it is available on a Canadian site that would be nice.

Update:
At the moment i am considering the Hitec HS-475HB.
robotshop.ca/hitec-hs475hb-servo-motor.html
It seems suitable because it has similar dimensions so i wonā€™t need to re-cut my metal parts.
Will this be suitable?

2

You probably need to figure out what killed the servos you have as it may kill any servo you use as a replacement.

3

I think it was too much strain on the servos. they are lifting up sort of considerable weight, and they arenā€™t perfectly calibrated so they are fighting each other slightly, but only indirectly. i have a feeling it was just the wrong servo for the job.

4

you will prob find that the 475ā€™s wont be strong enough, so i would go for these: robotshop.ca/hitec-hs645mg-servo-motor.html 645ā€™s!

i know they are more expensive and prob over your budget but you get what you pay for with servos so i would consider them!

the project sounds really cool!
how many segments (servos) will you have?

5

645s are definitely over my budget, but thanks for the suggestion. I have researched around and found some servo called the Tower pro MG945. i am a bit leery about this servo because i have never heard of Tower Pro, and it looks too good to be true ($14 at peakmodel.com/index.php?main ā€¦ cts_id=208 ). especially after my experience with GWS, i am afraid of cheap servos. anyone have experience with Tower Pro?

Also, thanks innerbreed for your comment. i guess i described my robot completely wrong. by snake i meant a chain of servos. but not at all snake - like. they form a sort of loop and the entire thing rolls around. it has 10 segments but i am thinking of downsizing to 8 to reduce strain on the servos. iā€™d post some pics but iā€™m entering it into a science fair and i donā€™t want this robot online until after the sciencefair (march - ish, maybe april)

6

yes too good to be true. i also once had this in mind, but trust me, they will fail you. there are a few threads on these! not good!

7

this sort of thingā€¦
youtube.com/watch?v=eOX6W2kF ā€¦ re=related

8

yes sort of like that. just that i donā€™t have as nice looking metal parts (iā€™m too cheap for SES), and it moves like a rectangle rather than an oval. It will also deform to take the shape of its surrounding terrain. iā€™ll start a thread on it in the projects section after sciencefair.

Thanks for the advice on the Tower Pros. Any chance you could point me to the threads about them? I heard that they are Futabas in disguise.

9

got my numbers wrong. its the MG995ā€™s that we have all talked about not MG945ā€™s. but this being said, the manufacturer (Tower pro) are shocking!!

LM uses the best they can find so thats why the 645ā€™s are top for many of their application.

here is the link to Tower Proā€™s MG995ā€™s!!
lynxmotion.net/phpbb/viewtopic.php?t=4576

10

okay i guess i am not getting the tower pros then.
i guess iā€™ll do Hitec HS-475HB. it has less torque than the servos i had been using, but i can downsize my robot from 10 down to 8 segments if i need.
(no way i am doing 645s, too expen$ive)

thanks

11

yeah its a shame to get set back by the cost of servos. down-sizing the amount for segments will help.

good luck with the sciencefair, and cant wait to see it.

12

There was a time when I thought regular plastic gear servos were ā€œgood enough.ā€

After tapping a wall with RC10B4 (1/10th RC buggy) and replacing the gear set twice (it gets costly) in my ā€œstandardā€ servo, I finally started to look into metal geared servosā€¦

For robotics, you really should consider getting metal geared, dual ball bearing servos with the appropriate torqueā€¦

The only time I would drop another nylon or karbonite geared servo would be if it was just carrying some sensors (very light)ā€¦

Like many things, not just robotics, if you decide to save money by going for lower price, the end item that you will finally end up buying will cost more, since itā€™s that cost, plus the cost of the cheap servo that made you realize thisā€¦

All is not lost, I would stop using the cheap servos for your snake bot, get some proper ones (do some load calculation or estimation and choose the right torque/speed), metal geared (steel or titanium), dual ball bearings (your slop will not increase as rapidly as nylon bushing ones)ā€¦

Keep the cheap servos for something thatā€™s not torque intensive, such as carrying sensorsā€¦

13

wow sorry everyone i have been away from this forum for a long timeā€¦ anyways, science fair had decent success, unfortunately i did not go to nationals, unlike the previous year. anyways, the whole robot was a bit wobbly due to crappy construction. if this were anything other than a sciencefair project i would post my new design ideas like crazy, unfortunately that could cause some issues. anyways, i ended up with some futabas with karbonite geartrains, and they did not let me down. iā€™ll upload some pics of the finished robot later. It was a very sketchy prototype, i am right now deciding whether or not to continue the project. this year my budget is a bit over $1k, so i will have a bit more room to breathe. I plan on getting some laser-cut parts if i continue with this. if i donā€™t, im gonna get a hexapod and mess around :smiling_imp: .

thanks for the advice, i guess i will start a thread for this project if it gets off the ground