John..no offense meant and apologize for an inadvertent slight
That term is often used throughout my early career in design. Even
Uncle Bill Leckilkner (who taught me my hands and design acumen) use
that term often...as he did NOT normally use a torque wrench, but was
'good' for it with his hard knock schooled hands
I did mention preload or tension for the shank. Even 'tried' to explain
why proper tension is very important here and many, many times
on other threads. Did also mention that anyone working on an ISO
certified production facility would be fired for not using or following
instructions on torque for a fastener
Also stated that there are years of courses in basic engineering that
folks here so cavalierly dismiss and have had a guy call it gobbledygook
Missed is that this stuff is of life and limb, but I am in the vast
minority vs the fat part of the bell curve (call them the herd)
Also lost respect for a few who I 'thought' had at least a basic understanding
or appreciation of how it is NOT a game, but serious engineering
or re-engineering discussions
So, am gone for a while as have more hobbies needing attention (OBTW
no longer just a hobby this forum, now serious as too many PMs and
even my email in box with real issues caused by poor to even dangerous
Not everyone will go to a pintle, nor weld, nor anything else...though there
will be some
Hope brought this down to a level for some here to understand what
the heck this is for an designer
Here is the formula to figure out the clamping force. Clamping force is
calculated according to the dynamic loads and shock loads the
designer worked out for the worst case...plus margin. Once they
have the clamping force needed, then the process of selecting a
bolt (shank) size, or bolts. Along with grade and another whole
discussion on the selection of grade...cascading failure is one
where you want the lower grade on the part you wish to fail first, etc
T / KD = P
D=shank dia or nominal thread dia
K=Constant and is the co-efficient of friction on the bolt/nut
On the constant and is the friction between the mating surfaces that the torque
must over come *BEFORE* the fastener sees any clamping force... 0.16 is a very
smooth and greased mating surfaces...rusty and rough surfaces would be around 0.75, or more (these numbers are IIRC, as it has been decades since the last
time I've calculated a fastener for a design)
Chose 1" shank dia for ease of math
Two thoughts on this.
The ball instructions of 450 ft/lbs
Theory of 150 ft/lbs & cotter/castle will do
Just the numbers for now
450 ft/lb / 0.5 x 1 = 900 lbs of clamping force
150 ft/lb / 0.5 x 1 = 300 lbs of clamping force, along with a cotter or castle
But there is more than just the clamping force, though the main component.
There is the hole that the ball shank goes through. It has tolerance, meaning
bigger than the shank by some designed in margin to allow the shank to easily
pass through...but that is part of the problem...that tolerance
If the hole is sized as a press fit, it will still have some movement of the
shank in that 'tight' hole
Movement is a VERY bad thing for this application
So if the clamping force is 1/3 of the designers spec, then the shank will
most likely move around in that hole...even it it has a cotter and castle too
Banging and over time will work the metal of both the shank and hole.
Moving like that to bang will also allow the nut to back off, but okay...the
cotter will stop that via interference...but the castle *WILL* back off, unless
it too have a cotter in the castles
Here is the biggie over and above the previous...the shank will be allowed to
lean and/or bend because it does NOT have the preload spec'd in by the designer
Since not enough preload for that application (meaning the static and dynamic
loads the designer worked to)...the loading will pull/push/etc the ball that
will then lever the shank.
All of that movement *WILL* cause other things to wear faster. Like the coupling
and it's latch
If tightened to the spec of 450 ft/lbs, which creates 900 pounds of clamping
force...it should not move when exposed to expected forces
Must qualify that...always say things designed are designed not for the good
days out there, but for the worst day out there when Mr Murphy crosses your path
'Maybe' the cotter/castle will keep the nut on, but with all of the increased
wear and tear...will the coupler hang onto the ball? Will the ball bend over
enough to create a condition where the couple dome recess will allow the ball
to move out of?
The more I read on these forums...the more concerned get about the setup next
to me going 65MPH or more...
Fastening science stuff...cotter pin & castle nut are for different applications
They are for 'not' too tight, but just enough for bearings or some such that needs
to be allowed to 'move'.
Clamping force is NOT the goal, but maintained 'gap' is
Curious why folks do NOT trust the designers who wrote the specification for the
torque on 'their' design
Know and understand that am in the vast minority because this is technology in
discussion...but...why don't you folks believe the instructions?
Would love to have some of you folks hands on build any engine without using
a torque wrench...components and machining costs out of your own pockets (your
skin in the game)
Doesn't matter small block, big block, diesel or even a 2 cycle chain saw ICE
Then ask it to go +100K miles under very hard conditions
Oh well...moving on...and get off this soap box...
To the OP, thanks for posting this. Looks like you made an expensive mistake and by posting this you may keep others from doing the same thing.
Ditto that...many thanks for the OP for posting and getting the spears
and arrows in the back... :S Hope you stick around
In case folks didn't understand why asked what PSI/age/etc of the
impact gun...is that all air impact guns torque is at a specified
PSI and CFM. Oiled or not too. Over time the gun wears. More so if
not taken care of properly (oiled is the biggie) and will lose it
ability to meet torque spec. All my air tools get oiled before hooking
up and during their use
Some depend on torque sticks, which I have and use, but do NOT trust
them. Recheck with a properly set torque wrench and often find not
up to torque (most likely dirt/grim/etc on the mating surfaces)
Lock washer, nylon slug, etc assumes already tightened to spec. This
kind of 'back up' is no different than wired fasteners on airplanes,
race engines, nuclear plant stuff, military stuff, etc and more etc
All are tightened to spec by trained professionals who either know
what they are doing, or under threat of losing their jobs if they don't
Plus super critical will have a 2nd person double check the torque
Of course not rocket science here, but life and limb is on the line
Some of you 'Farmer Tight' folks have the risk of over tightening and
that then will have the stud and/or nut not able to hold...even at
lesser torque...some will actually get it right...but...how would one
be able to tell?
The way of it is that all things have harmonics (vibration) and either
matches the natural harmonic and/or amplitude so high...as to stretch
the stud to even the threads ever so SLIGHTLY.
The nut can and will back off a bit. Over time, the torque (clamping
force) is no longer able to provide enough clamping force to withstand
lesser vibration & amplitude
Back to the OP...again, say much appreciate your posting for 'some'
who might learn from your near disaster experience.
You're thinking like that which you are-- an educated RV & tow vehicle enthusiast.
The average person has no clue about GVW, GCWR, etc etc
Key to marketing sometimes is to "dumb it down" to speak to the majority.
As neat (and progressive) as it'd be to see change, half-ton, 3/4' and 1-ton terminology won't be going anywhere anytime soon.
I'm not suggesting the marketing material go away.. Just that when we discuss things here, we use measurable and specific rating (I.e. The numbers)...
You're right, it would likely work on this forum as at least most here understand the numbers.
Disagree...even too much of the advice given indicative of not
understanding the numbers themselves, or what rating means.
How many times will someone say they are rated for XX,xxx lb trailer
because they read it in their manual. AKA...MTWR, but out of context.
How many times have 'some' tried to inform them that they need to go
out and weigh their setup to truly know what their 'actual' MTWR is
Or how many times will you read advisers here say GCWR is meaningless
Surprised someone hasn't posted a nice list of different brands & model years and their accompanying GVWs & GCWRs for reference.
Too many and confusing to most of the herd
Plus with this pure marketing verbiage...it covers every thing and
across many eras.
My 1980 C10 Silverado Big Ten (half ton of that era and the HD version
to boot) with a 6,200 lb GVWR was the BIGGER half ton of that year.
Regular half ton's of that year less than 6.2K GVWR
Today's regular half ton is in the +7K GVWR range
Then again it's Sunday, football's on, and making that list would be dangerously close to work.
There are many who will advise newbies that they can do it, as they
also have a half ton of the same badge (OEM)
Have been doing that for loong time with no problems
Have had 2 or 3 (can't remember anymore) PM me asking what the...
One guy wanted to sue the guy advising that he could do it. That
guy had one of the smaller GVWR 'half ton' from that same OEM, but
since smaller GVWR...burned up his diff and wanted to sue the adviser
The other guys said the trailer manhandled them, but how did that advise
buy do it?
Well, it turns out that those advisers have the "HD" version of half
ton for that same year, same OEM and had a +8K GVWR...well over 2,000
more GVWR...but still a 'half ton'...
We are not the herd. We are RV.net! We shall overcome!
Use that vernacular to get folks attention...
Am a technologist and bell curves a key component of most everything
done in design.
In design it is also known as tolerance. With the quality engineers
on my teams...it is part of their AQL (acceptable quality level) metrics
Using 'bell curve' does NOT get their attention as much as 'herd' (the
fat part of any bell curve)
What is your impact gun rated for?
At what PSI?
They do lose torque capacity over time...how old and how well maintained or used is it?
Without a torque wrench or some such, calibrated tool...no one knows what the
torque was on that nut.
What is the torque required on that ball/nut? The info is on the label/package/etc
it came in
Another thread on this topic here at this link: How often do you need to tighen your hitch ball?
Another thread on this topic...link below
t backed off ball caused accident
I was heading up to santa cruz ca. in my 40' american eagle I had my motorcycle in tow on a utility trailer. Before I left I had tighten the nut on the ball with an air impact driver the kind that you take lug nuts off a car or truck it was tight lock washer in place. safety chain hooked up all was good. traveling down the 101 near north Hollywood ca. I saw the trailer jumping in my rear camera as I slowed the trailer let loose breaking the safety chain and hitting another car. what a mess. I have never had this happen before but the nut from the ball was laying there on the freeway. now I am having insurance issues on the trailer and coach it was the vacation from hell and it's not over. The only type of ball I will use from now on is one with a cotter pin going through the bottom of the shaft. Uhaul carries them. Sorry for the sad story but i hope this will help others. I still do not understand why that nut backed off
The herd does NOT like real or meaningful numbers/nomenclature/badging
Marketing works so well on that portion of the bell curve that I call the herd
Hopeless...below are just some of the threads on exactly what you speak...plus
so many do not either understand what RATING means, and/or do not
believe in them...worst are the advisers who either don't understand
themselves and/or provide advice..."sure you can"...."been doing that
for decades or thousands of miles with no issue/problem"...
Or that most newbies will only own a 'half ton'...biggest vehicle they
have EVER owned/driven...so of course a monster to them...or that they
will read/hear/see marketing of the HD/MAX TOW/MEGA/SUPER/etc half ton
so it is more capable than then higher classes (+8K GVWR's)
Why another member went out and checked to find IIRC, 15 different
GVWR's all marketed as 'half ton'...and...all from the same OEM/badge
Careful...you will be called "The Weight Police" ! There is no
policing on any of these freebie forums, nor liability. Called that
as a derogatory to reduce the validity because they did not get what
they wanted to hear...or again, do not understand what rating means
and/or do not believe in them
Ratings, terms and opinions of what they mean... 5 pager
Ratings & specifications...is it that hard ??? 3 pager
The Problem With GVWR and GCWR 4 pager
should yave done my weight homework. 3 pager
Stay here mainly due to the numbers of PMs and newbies who might listen
and help them figure it out. Buddies dad came here and found what he
was looking for...but his is an old farmer and almost got killed using
bad advice here...another main reason I'm here...real world experience
of what can and did happen
Example of how folks get the wrong advice
Why so many packages almost impossible to open without a knife...even then
the thieves manage
We honest folks pay for their thievery and they know it.
Why I most always insist on opening it while still in the store and the few times
don't...too often screwed like this
Going back a few years was it Toyota that had a small diesel in a small pu?
Not just Toyota. Nissan, Isuzu, Mitsubishi and Ford also sold small diesel pickups in the US in the '80s. Good mileage, but the only one that had enough oomph to pull more than a kid's tooth was the turbocharged Mitsubishi.
Know a guy who still commutes with his VW mini pickup diesel
A real dog, but he doesn't drive hard, so a dog is just dandy for him
I bit the bullet and bought a 1 7/8" 3/4" drive socket and "T-Handle" breaker bar.
I will say that there's no way the existing ball was torqued to 450 ft/lbs. I was prepared to struggle for a while to get the old one off and it broke loose way easier that the 5/8" lug nuts do on one of my trailers!
This was originally installed by the the trailer shop that sold me the hitch.
I agree that you should be able to have a shop do it, but I also think that you either need to watch over their shoulder every step of the way or you have to **really** trust them.
Not just the 'shops', but also the folks who tighten it 'Farmer Tight'
Some match torque wrench tightened...some over to weaken the bolt...some
There was an old thread where a member drilled a dimple for a steel
BB on both the flat surface and the bottom flat of the ball.
That goes along with the discussion of wired, etc
Bottom line is that if it is torqued to spec, it 'should' not come
loose. That torque is what the designers calculated according to their
design spec loading
That design spec loading is for the worst case conditions and a lever
arm the length of the trailer...which can be over 30 feet long vs
the breaker bar in discussion (inches)
Why I recommend greasing the coupler/ball interface
The 3/4ton Suburban has over 1000# more payload than the Excursion.
2003 Suburban 3/4-Ton 2WD 8.1L(496ci)V-8 CurbWt:5620#, GVWR:8600#, Payload:2980#
That is just not accurate. Payloads for 8.1L 3/4 ton 5WD isright aroudn 2000 pounds. 2WD adds 300 pounds. 2980 might be a stripper 2WD 6.0L, but that big block is heavy.
Why always recommend going out and actually weighing your setup, axle
by axle. Both empty and fully loaded. As the only way to *KNOW* where
you are in reference to the ratings
Think about it...the options matrix is huge and these labels would then
have huge numbers of *DIFFERENT* payloads
One for the AC option. Another for 4x4. Another for power door locks
Another for power window. Another for automatic. Another for upgrade
interior. Another for upgrade exterior. Another for 2nd and 3rd row
seats. etc etc etc....then one with the combined AC & 4x4...then the
huge ETC for the multiplexing of all of the above or option combo
Then the other stuff folks load into and onto their TV's and
trailers...multiplexed with the above multiplexed label listings
They have to use the 'curb' and so many have no clue what that is
Here is a link to a thread where try to explain how it works and an
example is my Sub's simple math using the curb (link shows my last
smog test data sheet that lists the 'curb' for my 7.4L 2500, which
is the data from GM (all OEM's provide their curb to all DMV's for
this testing and other usage requiring a 'curb' number)
So according to how most folks 'think' it works...taking the GVWR of
8,600 minus the curb of 5,250 = 3,350 lb payload or cargo capacity or
They think an injector went and then when to hell from there in 15 minutes!!
I don't see that at all. No heat damage that I see on that piston.
Looks like it dropped a valve and BOOM.
No temp based damage at all
Question is why continue with the racket it MUST have been making....
Thought you said first time saw 220, right after fresh charge of synthetic along
with our religious maintenance with the good stuff...
And that the forward gears rock solid, but reverse gone
Oh well...I'm still going to add an extra external on mine...
Dislike this stuff immensely...mom'n dad owned a 'small' grocery/butcher shop
and slim margins
These things took directly from their pockets and hate how folks say your insurance
will make up, or you make so much already
After someone yelled that they could buy it cheaper at Safeway...dad had me
go around the store looking...some times a carton of ice cream left on top of
some dry goods to mess with us some more.
For me, bleeds over to folks who lie about a tuner or over loaded when they
bring their vehicle back for warranty work
Ditto checking most anything before leaving the store. Ditto have found stuff
switched. Like water filter (plain vs carbon filled), a 12 package of fasteners
to find 11 in it when get home...missed that tiny hole where they took one out
Can NOT remember HOW2 in all of vehicles that I work on
Dad's Caddy needed a pencil/pen/paper-clip poked into a hole in the radio while
turning it on/off. Maybe not radio, but a module next to it
Others hold two buttons while turning it on/off
Have to look it up on the glove box manual each time to make sure got it right
and not mixed up with the others
So they are NOT all the same...maybe same OEM, same model line, but check to be sure
Don, consider installing another external ATF cooler, as you camp in some tough
on automatic tranny places...me thinks you have lots of 'boy racer' in you too... :)
Stacked plate and either parallel or series to the existing OEM stacked plate
Have made my own with electric fan and thermal switch (plus manual switch) parts
in ready for the day when mine is rebuilt. No bypass, as long as the ATF goes
into the OEM radiator's in-tank ATF cooler
Series...on the 'tranny out' line to the OEM in-tank ATF cooler
Did one for a buddy who had a '95 7.4L TBI Sub and we could see the dash eng
temp gauge cool down when his 2nd external ATF cooler kicked in. He was noodling
a severe duty fan clutch like mine, but we lost touch and don't know what happened
He towed a huge dirt bike trailer and off roading when all that
cooling needed for ATF.