Hi. I just noticed the grub screws (Allex screws) of my dt700 motor's mount are way too loose and causing vibration. I want to buy a suitable Hex driver for that and use some threadlocker. What is the size of the grub screws? M1 or M2??? Also, are Hex-drivers normally available at hardware shops? And I found this threadlocker and the company has a branch in Hyderabad too: http://www.anabond.com/psc_thread_lockers.htm Is this threadlocker okay?

Vineet

Hyd, just take motor, or motor mount with you, to a respected tool dealer, and find an aproppriate one.. because, i found some inner play, between key and Allen key screw, while bought a key in to M2.. but later i bought an apropriate key from a tool shop, after taking motor with me..now serves better.. 

With the help of a vernier caliper (I got one cheapo but accurate for Rs.150/-) you can know what is the screw type. Got it figured out and cross verified it with shops in S.P. Road bangalore.

M3x3 = 3mm diameter with 3mm height. http://www.hobbyking.com/hobbyking/store/__6203__Grub_Screw_set_b_M3x3_10_Pack_b_.html

M3x4 = 3mm diameter with 4mm height. http://www.hobbyking.com/hobbyking/store/__6204__Grub_Screw_Set_M3x4_10_Pack.html

M3x20 = 3mm diameter with 20mm height.

For M3 a 1.5 allen key would be suitable. Invest by asking for a TVS make allen key, costs around Rs.8/- in SP Road, with M3x3 or M3x4 grub screw costing Rs.3.50/piece.

During one of my flights motor came off it's mount. So I used blue color anabond threadlocker (10ml for Rs.30). The grub screw surely held motor tight for many flights including many perpendicular crashes. Of course there was no intention of testing the thread-locker.

The problem came when I wanted to unwind the grub screw. Anabond just won't yield and in the process got my allen key damaged. Used a soldering iron to heat up the joint in a hope that the thread locker would give up. Had to scout for an allen key at SP road and got it opened. So be careful and have a few spares of 1.5 allen key. You may get it at an ordinary hardware/sanitary shop.

Can forum members suggest a way to "undo" a thread locker .... jisse ki saap bhi maar jaaye aur latthi (allen key) bhi na tute.

Heat is the best way to loosen threadlocked screws.

Thanks ashutoshn, roopesh sir and iamhuman!
And I forgot to tell you all a foolish thing I did: I was in an urgent need of threadlocker, but couldn't find it, so I used fevikwik and I want to remove it now. I heard a tinner or a paint remover (available easily in all hardware+paints shops) can remove fevikwik. Is that true? I am thinking of buying the Anabond 113E (medium strength, blue), is that okay or do I need to buy Red? Thanks.