Threadlocked.

[john stones 1 - Moderator]

Bought a model of someone, the servo screws have been threadlocked, doesn't appear to be a solvent, what's the thinking ? soldering iron tip, would I ruin the servo with the heat ?

[Simon Chaddock]

john

I presume you mean the screws holding the servo. I doubt if touching the screws long enough to soften the thread lock would damage the servo. It might damage the grommet, if there is one, but that is replaceable.

[john stones 1 - Moderator]

Screw holding the horn on Simon, it's well stuck.

[Denis Watkins]

If John Stones comes on here asking for help, then it has to be a real problem

You are almost doomed to damage the servo, as you well realise John

My own desperate measure would be to sacrifice the servo arm

Cutting slots down to split the arm off, then fit a new arm

[john stones 1 - Moderator]

Yep I feared the nurse, it's a top servo and a great big metal horn, dreading looking at the ailerons.

[J D 8]

Shock loading, tapping the screwdriver with a small hammer as you try to turn the screw may make it release if it is threadlocked and not fixed with something else like super glue.

[wingcoax]

Hopefully it will be 242 (blue) and should move with only a bit of shock.

[PatMc]

If the servo is out of the model or you can remove it, try leaving it in the freezer for 30 mins or so then heat the screw with a soldering iron for just a few secs or carefully hold the servo arm in a cup of boiling hot water. The sudden changes in temps may give enough variation to do the trick.

[Nigel Dell]

Posted by PatMc on 21/02/2020 16:00:26:

If the servo is out of the model or you can remove it, try leaving it in the freezer for 30 mins or so then heat the screw with a soldering iron for just a few secs or carefully hold the servo arm in a cup of boiling hot water. The sudden changes in temps may give enough variation to do the trick.

I concur have done it this way with success, sometimes just a few seconds of the soldering iron without the freezing works fine, is it a metal geared servo?

You can afford a little more time with the heat, also a small point but using a pointed bit seems to work easier than a flat blade bit but only in minimising the damage done to the horn for me.

[Andrew Calcutt]

Hold the arm in a vice and use an impact driver on it,make sure it is the right screwdriver bit.

[Martin Harris - Moderator]

If they've used threadlock then I'm assuming it's a metal geared servo? Localised heat from a soldering iron on the screw head shouldn't hurt the servo unless you leave the iron on for a very long time.

[Joe Beavis]

I am guessing that the thread is M3 ish, and the screwhead socket is now in less than new condition. I would favour Dremelling a new screw slot, preferably inline with the arm - you may be able to save it, select a screwdriver with the widest blade that will fit, grind it if necessary to really fit the slot, and apply steadily increasing torque. If you can hold it in the vice, that's good. If it is Loctite, then any heat will help. Also, if it is Loctite, I would not use an impact driver. It yields best to steady and overwhelming force! Good luck!

[john stones 1 - Moderator]

Ground a dremel wheel down first then slotted it, out it popped and I can't see any threadlock on it, all the others had and they came out easy.

[Stephen Smith 14]

Always use socket head screws on metal geared servos, can tighten them to the correct torque easily and are easy to remove.

[john stones 1 - Moderator]

Posted by Stephen Smith 14 on 22/02/2020 18:59:26:

Always use socket head screws on metal geared servos, can tighten them to the correct torque easily and are easy to remove.

Agree, replaced em.