# LA120 Blade "Deformed Thread" Lock Nut



## DCLINE (Apr 21, 2009)

My blades are held on with the "Thread Damageing" deformed thread lock nut. 5/8-18 UNF. I took the blades off to sharpen them and the nut damaged one of the shafts pretty good. I chased the threads and installed new grade 8 standard nuts and used blue loctite. Will the loctite suffice instead of the screwy locknut?

Thanks!


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## chrpmaster (May 5, 2004)

Welcome to the Tractor Forum DCLINE!

I have never tried that method of keeping deck blades tight. Was it the nut itself the problem or what? I have used the self locking nuts before and never had a problem so I am curious what happened on yours.

Andy


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## poonstang90lx (Mar 8, 2007)

> _Originally posted by DCLINE _
> *My blades are held on with the "Thread Damageing" deformed thread lock nut. 5/8-18 UNF. I took the blades off to sharpen them and the nut damaged one of the shafts pretty good. I chased the threads and installed new grade 8 standard nuts and used blue loctite. Will the loctite suffice instead of the screwy locknut?
> 
> Thanks! *


I would think that the blue would probably work, me myself I would use red, but I am sure the blue will get the job done.


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## DCLINE (Apr 21, 2009)

These are not the lock nuts with the nylon inserts. They are 100% metal and have factory indentions in the threads to slightly deform them to make them tight fitting. These nuts are not re-useable. They are a one time deal. This was the first time that the nuts had been removed to take the blade off for sharpening. One side came off "OK" and the other was very difficult and screwed-up the threads on the shaft. These are grade "8" nuts that are very hard. I think this is a very poor design for holding a blade on. Usually, it is a bolt holding them on, or at least that is all I have ever seen in the past on other mowers. If you haven't seen this type of lock nut before, Google "Deformed Thread Locknut". This was a factory installed nut.

Dan


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## tyco (Apr 22, 2009)

*locknut*

hey dcline, i just happen to build the L100 series...it will be perfectly fine to use the locktite or you can just put a lock washer with a regular nut on it....won't be a problem at all


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## MFreund (May 2, 2008)

Those "lock" nuts are becoming more common because they are cheap. I have never seen one mess up the threads. It could have been assembled cross threaded.

If you have enough thread I would use a lock washer. If not then blue Locktite will be fine. If you use red Locktite you will have to use heat to release the nut to sharpen the blades next time.


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## DCLINE (Apr 21, 2009)

Thanks for the replies!. I really appreciate the help!

Dan


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## crossthreaded (Apr 11, 2009)

I would probably find some of the metal lock nuts and put some anti seize on the threads to keep them from getting boogered up again


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## CHUMP101 (Jul 9, 2009)

There is a particular type of locknut that is used as a drop dead, won't fail locknut. These nuts deform the last thead as they are installed to the point of galling the threads. They are designed not to be reused plus the bolt can't be reused. My former employer used them to install planetary drive axles in front end loaders. They really work, but you have to know the ramifications.


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## tonyennis (Jun 10, 2012)

I can't get the blades off of my LA120. The blades are as dull as they can be now. Are you positive the nuts aren't metric, by the way?


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## stickerpicker (Sep 16, 2003)

tonyennis said:


> I can't get the blades off of my LA120. The blades are as dull as they can be now. Are you positive the nuts aren't metric, by the way?


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