Notorious Can't make 25t servo horn work with linkage. DS3225MG install

[Yazman]

True to form, I was unhappy with the stock servo that functioned absolutely fine it had nothing wrong with it, and decided to "upgrade" it and make it "better."

I think you know the end of the story. I now have a plastic 23t servo arm that fit the linkage perfectly but doesn't fit on the new 25t cheap server I bought. Likewise, the aluminum 25t servo arm fits the servo but won't work with the rest of the linkage. The horn is so close to the servo itself that there is no way to install the nut with the aluminum 25t that came with the servo. Even if I flip it upside down, it still doesn't work because then the angle of that middle piece is all wonky and messed up.

I don't even think grinding down the aluminum horn will work. Am I looking at just putting the stock one back in? We're ordering some 25t servo horn that probably costs more than the servo?

I'm such a noob

 

[Engineer]

Yes. You need a 25T servo horn. There are several options. The stock Arrma horn, a Hot Racing horn with metal linkage and an aluminum horn off of Amazon.


1: https://www.arrma-rc.com/part/AR340061
2: https://hot-racing.com/?partnumber=AON48SH25;c=938
3: https://www.amazon.com/Hobbypark-Aluminum-Clamping-Futaba-2-Pack/dp/B07Z1ZV1L5/ref=sr_1_10?crid=DAYR8F5T2RM1&keywords=Servo+horn&qid=1642884243&sprefix=servo+horn,aps,126&sr=8-10

 

[norcalsc]

servo horn needs an offset like the one on the top

 

[Yazman]

I chose the hobbypark since it was prime and cheap! Thanks fellas!

 

[Yazman]

Thanks all! The hobbypark horn fits great. I used the stock servo screw for the horn and it doesn't tighten all the way, it just keeps spinning. I just fed it a bunch of blue loctite; hopefully that'll hold lol.

 

[drkern88]

Yes. You need a 25T servo horn. There are several options. The stock Arrma horn, a Hot Racing horn with metal linkage and an aluminum horn off of Amazon.


1: https://www.arrma-rc.com/part/AR340061
2: https://hot-racing.com/?partnumber=AON48SH25;c=938
3: https://www.amazon.com/Hobbypark-Aluminum-Clamping-Futaba-2-Pack/dp/B07Z1ZV1L5/ref=sr_1_10?crid=DAYR8F5T2RM1&keywords=Servo+horn&qid=1642884243&sprefix=servo+horn,aps,126&sr=8-10

I had trouble with the HR metal linkage that came with the SS I got. However using the HR SS worked out well

 

[Engineer]

Thanks all! The hobbypark horn fits great. I used the stock servo screw for the horn and it doesn't tighten all the way, it just keeps spinning. I just fed it a bunch of blue loctite; hopefully that'll hold lol.

Are you talking the horn to the linkage? If so, put a locknut on it or it will loosen.

 

[slick2500]

Thanks all! The hobbypark horn fits great. I used the stock servo screw for the horn and it doesn't tighten all the way, it just keeps spinning. I just fed it a bunch of blue loctite; hopefully that'll hold lol.

It will come out, just use a 2mm longer screw to start.

 

[Yazman]

Are you talking the horn to the linkage? If so, put a locknut on it or it will loosen.

View attachment 195123

I mean the screw that goes through the horn to the gear on top of the servo. May try a longer screw like slick2500 suggested

 

[Engineer]

I mean the screw that goes through the horn to the gear on top of the servo. May try a longer screw like slick2500 suggested

Ahh, gotcha. Yeah - slightly longer screw would work.

 

[Yazman]

You guys rock! I put in a longer screw and confirmed that was the problem when looking at my stock rig and the upgraded one side by side. The longer screw actually threads in and feels firm.

So far I'm impressed with the egg roll servo I bought from the jungle store (Amzone)