Securing servo screws
#1
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Securing servo screws
The servo screws on the Hitec servos i'm using are vibrating loose, and in one, came out all together. The engine is a ryobi 31, so vibration is present. Would medium strength thread lock be good here to secure the small screws into the horn ?
Thanks
Cary
* EDIT: Did a search on this and found out that Locktite will attack plastic servo horns. Instead use CA to secure the screw to the spine.
Thanks
Cary
* EDIT: Did a search on this and found out that Locktite will attack plastic servo horns. Instead use CA to secure the screw to the spine.
Last edited by mustangman177; 03-09-2014 at 11:34 AM.
#5
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And how do you get it back out?
Are we talking about metal gear servos or plastic geared servos? I've never heard of screws vibrating out of plastic gears before since the holes are so tight anyway. A thin piece of teflon tape would probably tighten it up though and would still be removable. For metal gear servos, put a drop of medium threadlocker in the hole, not on the screw. That will let you lock the screw in place without any worry of damaging the control horn.
Are we talking about metal gear servos or plastic geared servos? I've never heard of screws vibrating out of plastic gears before since the holes are so tight anyway. A thin piece of teflon tape would probably tighten it up though and would still be removable. For metal gear servos, put a drop of medium threadlocker in the hole, not on the screw. That will let you lock the screw in place without any worry of damaging the control horn.
#6
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Most Hitec servos with metal gears have a small star type lock washer with the control horn screw. You may have lost it. I had the same issue a few years ago and Hitec did recommend a very small dab of blue thread locker. But I came to prefer a surface mount application of silicon or a dab of hot glue. Much easier to remove when you need to.
#8
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Thanks for the advice. I too have never had this issue. The engine is a Ryobi 31, so vibration is definitely a problem. I still am using the star type metal lock washers. Have applied the RTV silicon to the screw threads. Will check screws after the next flight.
Cary
Cary
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I had the same thing happen on mini metal gear servos on a .15 size plane. It could fly 3-channels easily. One time the plane landed with both aileron pushrods hanging straight down from the ailerons with the servo horns attached. Star washers resolved the problem but the next step would have been a very small droplet of blue loctite.
#10
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I don't see why anyone is resistant to use loctite on metal gear servos. That's exactly the sort of application the stuff is made for. It won't make it hard to get the servo horn off again when you need to. It only provides enough adhesion to keep screws from vibrating loose on their own.
#13
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Loctite is the way to go on metal geared servos when using metal arms. Even though you apply the loctite to the threaded hole only some vapor will get to the plastic arm and you might have an issue. The first thing to do though is to get rid of the crappy screw that comes with the servos and order up some 2.6mm socket head screws. With the better screws you can get the screw tighter and then if using metal arms apply loctite, if using plastic arms then stake the screw with RTV.
#15
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It is not advisable to use silicon RTV anywhere near electronic assemblies as the fumes are very corrosive. They do make a special formula for use in electronics but it is quite expensive.
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Bob
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Hi!
I thought we were talking of the four wooden screws holding the servo to the wooden tray...not the 2,6mm screw securing the servo arm.
I have never in my 40 years flying R/C had a servo arm screw comming loose! Just tightening it!!!!
I thought we were talking of the four wooden screws holding the servo to the wooden tray...not the 2,6mm screw securing the servo arm.
I have never in my 40 years flying R/C had a servo arm screw comming loose! Just tightening it!!!!
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Thanks for all the replys.
#22
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Oh yeah, then you were right Jaka. A drop of thin CA in a wood hole does wonders for keeping the screw where it belongs. It swells the threads a little and hardens up the wood so the screw won't ever come out until you are ready for it to.