Re: Destructive Lock Nuts Suck

On Fri, 12 Apr 2024 13:36:58 -0700, Bob La Londe <none@none.com99>
wrote:

On 4/12/2024 1:26 PM, David Billington wrote:

On 12/04/2024 21:14, Bob La Londe wrote:

I recently had to install new axles on a trailer in order to get
working brakes on the trailer... Don't lecture me about how you could
have done this or that and not replaced them. They were oddballs and I
wasted a couple weeks looking for other solutions.
>
The u-bolts that came with the new axles came with the destructive
style lock nuts. I don't mind to much. I hoped to never have to deal
with this again on this trailer anyway. On my second run to go pick up
a truck and haul it halfway across the state over some mountains and
some modestly substantial grades and weave through the Salt River
Canyon two nuts came off.
>
When the nuts came off I don't know, but when I went over a bump the
axle popped off the springs and the tire slammed into the tire behind.
I had just hit 65 mph and it suddenly felt wrong. I was running empty
and all of a sudden it felt like I was running with a load. I glanced
at the mirror and smoke was pouring off those tires so bad I thought a
hub was on fire. Fortunately, there was on old stock yard just ahead
with a lot of flat ground out front where I was able to safely pull
out somewhere west of Coolidge. The axle coming loose turned out to be
an easy fix. Since I was still running empty I just jacked the side of
the trailer up, rolled the axle back in place, and ratchet strapped it
tight. Then I whipped out my cell phone and entered NEAREST HARDWARE
STORE into the search window.
>
The U-bolt that had fallen off was just barely hanging onto the axle
still by the extra friction of the threads. The other U-bolt was still
attached to the cross plate by the nuts. At least I wasn't wondering
where in small town Arizona I was going to find U-bolts.
>
There was a Tractor Supply store in Coolidge that had TWO (2) (just
two) 9/16 fine nuts. They were in the wrong bin, but I found them.
With that, a couple fresh lock washers, and copious amounts of red
high strength Permatex thread locker I crawled under the trailer in
the parking lot to fix it.
>
Coming back I stopped and checked the trailer and my load at every
brake check lane and pullout. With a 3/4 ton Dodge w/ Cummins on the
back I made it back through the mountains and across the Salt River
Canyon almost with out incident. Somewhere on a long flat Southwest of
Globe/Miami I glanced in the mirror to see one of the hooks for a
front strap laying on the trailer deck. The strap broke where it went
over the frame.  Fortunately I had left the winch cable tight or I
might have lost the truck.
>
I'm too old for this sort of adventure. I prepared for everything I
could think of. Brought tools, and materials for emergencies, and did
everything I could think of to prevent problems before setting out.
>
Yes, the nuts were torqued down properly both times. LOL.
>
Yeah, I know... there are plenty among you who can tell me everything
they think I did wrong, but at the end I made it home. Now I have to
get that truck back off the trailer.
>

Good to hear no serious damage or injury. What do you mean by a
destructive locknut, It's not something I've heard of before. I wonder
if it was poor quality hardware. I was reading recently about a guy that
was rebuilding the diff and final drive in his car and decided to use
new bolts for the CW fixing but they failed when tightened before he
reach the correct torque, apparently made in Asia, he re-used the
original ones in the end and no problems.
 

>
I know you guys have to know what I am talking about.  There is a type
of lock nut that is dimpled or punched that partially mangles the
threads when installed to lock it in place.  These have square punch
marks on the flat.
--
Bob La Londe
CNC Molds N Stuff

 They are called a "prevailing torque"  "top distortion" nut -or a
"side distortion" nut. There are also "two way" locknuts Then there
arer "gripco" "crownlock" nuts
 NONE of them are inherently "destructive" and all are considered
"re-useable"
 There are also "stover" nuts and "FujiLoks"

 All of these can be used in various temperature situations including
under cowl in aircrafdt - while "nylock" and "fiberlock" are
restricted in aviation - and should be used with caution anywhere
higher temps are anticipated.
 The only "destructive" locknuts I've run into are stainless steel
nuts - paricularly on stainless fasteners - sometimes even with
anti-seize, which gall and microweld themselves together - - - -   The
square punch marks centered on the flats sound like possibly 2 ways.
Not flanged nuts, right? What grade bolt? Using prevailing torque nuts
designed for a higher grade bolt CAN make them "destructive"