The rotor blades on one of my commercial drones are held on by an M3 set screw that goes through the blade root into an alloy plate. The screws are threadlocked in but are subject to a lot of vibration.

After an incident last year where I lost a blade I am really keen to avoid that happening again.


I need to replace all of the blades so will have to disturb the threadlock.

The screws will be new but the alloy rotor head will still have traces of locking compound. Should I be cleaning out the old thread lock somehow before reassembling with new threadlock? Is there anything else that is critical to getting a good lock?

Once the screws are in I would like to put some marker paint on the heads so I can see if they are rotating out.... On full size aircraft this works really well... Any idea what I could use for this? Tipex isnt really manly enough....

[Edited on 7/5/16 by tegwin]

GBS sell a Yellow paint , nut/bolt marker.
http://www.kitspares.co.uk/index.php?route=product/product&keyword=paint+marker&product_id=1102

Aha, that'd do the job. Thanks

There are special low viscosity grades of Loctite for small diametre fine threads.

quote:

---

Tipex isnt really manly enough....

---

Torque seal... Cheaper than GBS stuff...

quote:

---

Originally posted by britishtrident
There are special low viscosity grades of Loctite for small diametre fine threads.

---

Search paint pens on ebay

quote:

---

Originally posted by tegwin

quote:

---

Originally posted by britishtrident
There are special low viscosity grades of Loctite for small diametre fine threads.

---

Thats an interesting point. Just looked at the pot of threadlock I was going to use and it says for threads over 1/4".... So that's clearly the wrong thing..

I see they do low, medium and high strength.... I wonder how strong the low strength stuff is!!


Thanks for suggesting torque seal, seems pretty cost effective.

---

Have you balanced the props? There shouldn't be a huge amount of vibration. If not then prop balancers are available cheaply or make one as I did.

As for thread lock, have a chat with a local model shop. I've always found they are willing to help.

Yeah I'd say prevention is better than cure here, get the assemblies balanced properly so the only vibration is turbulence induced from the arm or wind.

Loctite 241 is for small components 542 also works

quote:

---

Originally posted by Bluemoon
Torque seal... Cheaper than GBS stuff...

---

Loctite 243 will do the job nicely, it's medium strength but small screws can still be undone without the need for heat (unlike the high strength grades).

Ian