DO NOT USE LOCKTITE ON DS821

[Deohgee]

I cant believe I did this:arggg:
When installing the servo wheels on the DS821 servos (supplied by my Spektrum dx7 radio) I decided to use the blue locktite on the screws to secure the horn wheels....BAD MISTAKE!!!
The Locktite had weaken the middle gear and broke in half.....they literally fell off while I was working on another area of my heli............

I thought the gears were made of metal...evidently not......not sure what material gears are made of.

Deo:arggg:

[odieser]

The gears are plastic use a little ca if you want but a little longer screw which will go into the gear further is the answer as they have had a tendancy to break near the servo case as screws are too short but yes no loctite it breaks down the plastic to goo

[Deohgee]

Thanks Odieser,
What length is recommended and where can I buy these?

[BarracudaHockey]

What helicopter?

FWIW you never use locktite on nylon, karbonite, or any type of plastic.

[Deohgee]

T-REX 600CF E

[odieser]

http://www.readyheli.com/JRPA232L_Servo_Arm_Horn_Screws_Long_10_p/jrpa232l.htm
Deohgee these are the ones you need
Mark

[marchambault]

As per JR / Spektrum ... do not use thread lock on DS821

http://www.jrradios.com/Products/TechnicalSpecs.aspx?ProdID=JRPS821

"Important: Do not use liquid thread lock with the DS821 servo!

Do not use any form of liquid thread lock to secure the servo arm screw to the output shaft of the DS821 servo. Chemicals in these liquids react with the polycarbonate gear set causing the plastic to become brittle, fracturing the final output gear."

[jeffk]

Honestly, I'd open up the servos and rebuild them before I'd try to use them like that. It doesn't sound very safe to me, especially on a flying lawnmower. Those gears see a LOT of torque when maneuvering and if one of them fails in flight, you're done. The gears are likely soft(er) now and could strip out in flight.

Not only that, but the DS821s are not recommended by Spektrum for use on helis. I use them in my planks where they work beautifully, but I spend the extra coin and buy decent cyclic servos for my Trexes.

[MXRACERX43]

DS 821 bad servo for a Trex 600.:thumbdown:

[Deohgee]

Thanks everyone.

MX, why do you think the DS821's not good for 600?
I've heard others say they have not had any problems..
Would like to hear what problems you had.
Thanks,
Deo