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threadlocker stronger than loctite 270 ??
Posted: Sat Jul 07, 2007 11:47 am
by modman
anybody got ideas about a permanent threadlocker stronger than loctite 270??
the threadlocker will be used to locate a nut on a stud where the thread changes size 20mm unc to 22mm unc.
engineer says i am not allowed to weld the nut to shaft (undercutting thread, surface raisers yada yada)
it will be permanent and of coarse needs to be strong.
heat and oil are not major issues.
i was quoted to make the studs out of a larger solid bar and have the 'nut' machined as part of the whole stud but not even a politicians super comes close to the cost
thanks,
David
Posted: Sat Jul 07, 2007 12:08 pm
by nastytroll
sounds like your talkin 3/4 unc to 7/8 unc as it is an american imperial thread. I would use prob 680 locktite but only put it where the nut will finish n wind the nut over it. It will set inside the nut n blow the rest off with compressed air n wash with metho or similar. 680 is bearing retainer or I think 660? shaft retainer. very hard to break but can be done if heated with an oxy.
Posted: Sat Jul 07, 2007 5:02 pm
by Vulcanised
use Loctite super nut lock..... it's red!! the bearing retaining one does work, but not as good. If you want it to lock super tight, use the 720 primer spray as well to clean it.
Posted: Sat Jul 07, 2007 5:08 pm
by Spimon_NH
Are you allowed solder/braze it on?
Posted: Sat Jul 07, 2007 8:00 pm
by modman
solder/braze????:P
will have to check with the engineer.
stud is 4140 so as long as it cools by itself material integrity will stay.
david
Posted: Sat Jul 07, 2007 8:45 pm
by Shorty40
I have some Volvo Metal Adhesive and I have snapped bolts trying to undo them after using this stuff
Volvo Metal Adhesive (Contains Acrylic acid, hydroxypropyl methacrylate)
Strong stuff
Posted: Sat Jul 07, 2007 10:19 pm
by Shadow
might be a stupid idea, but could you just put two nuts on and lock them up to eachother?
Posted: Sun Jul 08, 2007 12:53 am
by Spimon_NH
It's been a while since I did any materials science subjects but I think you should be able to get away with soldering (possibly not brazing) without causing much disruption to the microstructure.
Soft solder melts at about 180 deg'C (possibly higher for a suitable solder for 4140). I don't think HAZ really came into it until about 890 deg'C.
If I remember correctly (it's been a while and it's late!) brazing requires about 420 deg'C so might not be as safe.
Then again, some of these 'glues' people are suggesting sound mighty impressive and could be easier.
Anywho, something to ask the gingerbeer.