View Full Version : Spindle Bolt - How Tight?
I flew yesterday and during my second flight, I heard an explosion after my blades shot out from both sides...fortunately, it was a good 75 yards in front of me (and my son) so totally out of harm's way....and the damage, well, could've been a LOT worse!
So I thought I cranked the spindle bolt tight enough (with blue loctite) but the question is, should I have cranked them down even tighter (like as hard as I could)?
Casualties of this:
Boom, TT, front/rear TT Gears
Main Bearings
Main Shaft (first time I bent one of these)
Canopy
FBL main blade links
Swashplate - it might be ok, but wanted the Quick UK one anyway
ESC - well, it was mounted inside the frame w/ double sided tape and when the bird landed nose first, the ESC pulled loose from the tape and hit the motor which dented one capacitor and sheared off some of the Red power wire.
Bottom line...I guess I should have cranked the bolts as tight as humanly possible.
teshreve
03-28-2010, 06:01 PM
I am using MIP drivers, which have nice big handles and really high quality tips. And I put some serious force (and thread lock) when I tighten mine. A friend actually uses two socket wrenches with the MIP speed bits and REALLY puts those on tight. That is going a bit far IMO, but he hasn't had any problems either. Hard to argue with results.
http://www.miponline.com/MIP/STWrench_files/original.jpg
minititinflyer
03-28-2010, 06:11 PM
yes as tight as u can and lock tight and did you use GREASE WHITE LITHIUM on the thrust bearings?
povern
03-28-2010, 06:13 PM
1/4 to 1/2 turn before breaking the bolts.
povern
Yes, I used white lithium grease on the thrust bearings.
OK, clearly I should've tightened them down more. I guess I was afraid I wouldn't be able to get one bolt out in the future when doing maintenance. One time, I had to dremel a notch in one side of the spindle shaft in order to get the other bolt out. I guess I'd much rather have to replace a $3 spindle than what I just went through.
Thanks guys...gonna put some serious muscle into it this time around!!!
ualdrivr
03-28-2010, 07:31 PM
Yes, I used white lithium grease on the thrust bearings.
OK, clearly I should've tightened them down more. I guess I was afraid I wouldn't be able to get one bolt out in the future when doing maintenance. One time, I had to dremel a notch in one side of the spindle shaft in order to get the other bolt out. I guess I'd much rather have to replace a $3 spindle than what I just went through.
Thanks guys...gonna put some serious muscle into it this time around!!!
Now hold on a second Phillip, I mean, they have to be tight but if you over tighten them too much then you run the possibility of stress fatiguing the bolt and then you run into the same problem.
This is a good thread on the 700 forum, where a guy had the same problem like yours but he over tighten the bolts.
http://www.helifreak.com/showthread.php?t=171363
So I guess, the conclusion would be that the tightening of the bolts is subjective. The important thing is that the spindle and the bolts have to be free of manufacturing debris and grease. Bob suggests and I do it on every build, that you submerge the spindle and the bolts in alcohol for a few minutes, then let them dry thoroughly, apply the LockTight in the threads of the spindle and then assemble.
If the LockTight has time to cure, you should have no problems. If there is any grease in there, then the LockTight is useless.;)
Hope this helps. Now get busy rebuilding:Bang:). How is things otherwise? Go to my profile and look at my albums to see what I've been building and messing around with since February...:banana
:cheers Panos
Great call submerging the spindle in alcohol...I'm definitely going to do that this time around.
She's actually rebuilt, but I sent the ICE to CC today for repair. I don't know that she definitely needed it, but why risk it with that much $$ in the air. I'm gone for the next 10 days anyway so it's not like I'm in any rush.
Thanks for the tips guys! On the bright side, at least I'm finally using up all my spare parts.
ps. nice 700LE Panos!! we'll def get out this Spring!
By the way, my issue was not the same as what happened with the 700 from that thread. My bolt backed out while his snapped....that would make me really really nervous!
azheliguy
03-29-2010, 09:20 AM
Shef, Sorry about your crash.
I try to push and pull on the blades after two or three flights. I also try to get then tight and I use blue loctite and clean with alcohol:thumbup:
ualdrivr
03-29-2010, 09:35 AM
By the way, my issue was not the same as what happened with the 700 from that thread. My bolt backed out while his snapped....that would make me really really nervous!
Yes Phillip, I read about the fact that the bolt backed out, I was just trying to make a point that the problem can occur both ways. Either the bolts are not tighten enough or they are over tightened.
There is a happy torque setting that the bolts like, what it is no one knows because the manuals don't specify:thinking. I think the most important thing is that the spindle is clean and dry so the LockTight can do it's job.:YeaBaby:
Come out on the Island this Spring, we'll burn some Nitro:YeaBaby:.:)
Can't wait!
Hopefully, I'll find that happy bolt torque by then :)
Wahoo
06-11-2012, 10:24 PM
My problem with tightening the spindle bolts tight is that the blade holders start to bind if I get them as tight as I would like, even with one shim on each side. Its like thiner shims are needed, but I don't know where to get them.
rcflyerheli
06-11-2012, 11:30 PM
My process is that I soak the spindle threads in alcohol, then use a Q-tip to run in the threads and rub out whatever is in there. I also use loctite 243 which is an oil tolerant threadlocker, just in case you missed some cutting oil.
As far as tight, I wouldn't worry about not being able to get both bolts loosened. One or the other will loosen and then you can get the spindle out and use a grippy or one of the other spindle wrenches to get the other one loose. I use an appropriate "L" shaped allen wrench on one side when I tighten and an Align knurled handle wrench on the other and tighten as hard as I can by hand. I learned early on with a 400 spindle bolt letting go and hitting me on the kneecap. I definitely don't want that experience with a 700 sized heli.
trexpup1
06-12-2012, 08:08 PM
I use brake cleaner to clean out anything with an internal thread,that little spray tube gets right in there. I take the part out side and hold it over the garbage can while wearing safety glasses and facing the part away from me. Things can get messy do not try this inside.
Cheetah62
06-13-2012, 10:25 AM
Using this as a rough guide:
http://www.imperialsupplies.com/pdf/A_FastenerTorqueCharts.pdf
I would think the metric cap screws we use most - M3 and M4 bolts - are rated somewhere around 2 ft./lbs. This would be about six or seven lbs. force on a hex wrench three or four inches long.
As the above thread shows, there are risks in both under- and over-tightening.
Personally I tend to favor clean bolts (washed in alcohol), liberal use of Locktite and a firm torque. Iron-fisted smack-down can crack or seize the bolt and leave hidden damage that could cause catastrophic failure.