# Clevis Vs. Shackle Vs. Clevis . . . PLEASE define . . .



## RonHebbard

Decades ago, if I called something a clevis someone would correct me explaining it was a shackle. You can see where this is going. If I called something a shackle, I'd be told I was wrong, it was a clevis. About a week ago I asked CB if we could make this a 'Question Of The Day' as the current question about the quantity of dimmers has been up for many a moon. I was told my query could not be posted as a Question Of The Day as I couldn't provide an answer. Silly me! I didn't know a Question Of The Day couldn't be posted without a succinct / definitive answer. 
Next I took my query to a friend of some 30 years who's spent at least the last two decades teaching college level millwrighting to folks apprenticing to become journeyman and / or Master millwrights. My associate provided two PDF's from his course of study but, in typical college fashion, I perceive them to be verbose and far from concisely definitive. I questioned my friend further and the more he looked into this, the more convoluted the differences and similarities become.
*Thus my query:* @egilson1, @Whatrigger, @derekleffew, @dvsDave, @skatersdad and @anyone else. 
*What are the definitive differences between a clevis and a shackle?*
From the digging I've done thus far, here's where things seem to be heading:
It appears a clevis is a three piece coupling device with two parts attached / welded to items and only one loose, non-attached, piece with that piece being a clevis pin. 
For example: You may find the female portion of a clevis welded to the frame of a tractor or caterpillar-tracked bull dozer and the male portion of a clevis permanently attached to the tongue of a trailing device; such as a cart, plow or tiller for instance with the only loose, readily removable, part of the clevis being the clevis pin. 
Typically, the clevis is arranged to afford a reasonable amount of vertical movement or play and an appreciable amount of lateral movement. A shackle, on the other hand, appears to be a two (versus 3) part device with both parts loose / conveniently transportable, such as shackles often used to temporarily couple items used in rigging.
Some sources informed me that clevises had non-threaded clevis pins while shackles ALWAYS had threaded shackle pins although sufficient Googling appears to show both clevises and shackles with threaded and non-threaded pins. 
*Come one, come all.* *Please* educate and elucidate this poor old blind geezer.
Toodleoo!
Ron Hebbard.


----------



## gafftaper

Well you have me interested Toodles. I thought Clevis was just an old term for Shackle, possibly a brand name from back in the day. 

@porkchop would be another good person to call out.


----------



## derekleffew

Clevis is Butthead's friend.
Shackle is the sound a chicken makes.


----------



## RonHebbard

derekleffew said:


> *Shackle is the sound a chicken makes.*


When you chain up its cackle with a shackle no doubt.
Toodleoo!
Ron Hebbard.


----------



## porkchop

I've been paged, but it's the first day. Now I'm confused.


----------



## BillConnerFASTC

Well, first all shackles are clevises but not all clevises are shackles. A shackle is a name for a specific piece of hardware. A clevis is more if a design or approach, a part of another piece, and less the name if a specific piece of hardware.


----------



## porkchop

Since Bill gave a real response I'll repost my original answer before I rethought the QotD rules:

My understanding is that clevis is a more generic engineering term for a load bearing element where the load is inserted within the device and then secured with a pin of some type. A shackle is a specific tool made for rigging. I also feel like the straight walls of the clevis that are designed for some amount of rubbing against the load are an important element of a clevis that generally you don't want on a shackle.

Mcmaster-Carr calls this a "Rod Clevis with Pin" and I am sceptical of anyone who would argue the rod end is a shackle.



That being said, does that make a spigot a clevis?


----------



## What Rigger?

Well, in my world, this has always been a clevis. But that doesn't stop the current employer from publishing internal documents calling a clevis pin a "detent pin". And then a shackle is a shackle.


----------



## gafftaper

porkchop said:


> I've been paged, but it's the first day. Now I'm confused.


This started out in rigging, but somewhere along the way this was moved to become the QOTD.


----------



## RonHebbard

BillConnerFASTC said:


> *Well, first*


And second?
Toodleoo!
Ron Hebbard.


----------



## RonHebbard

porkchop said:


> Since Bill gave a real response I'll repost my original answer before I rethought the QotD rules:
> 
> My understanding is that clevis is a more generic engineering term for a load bearing element where the load is inserted within the device and then secured with a pin of some type. A shackle is a specific tool made for rigging. I also feel like the straight walls of the clevis that are designed for some amount of rubbing against the load are an important element of a clevis that generally you don't want on a shackle.
> 
> Mcmaster-Carr calls this a "Rod Clevis with Pin" and I am sceptical of anyone who would argue the rod end is a shackle.
> 
> 
> That being said, does that make a spigot a clevis?


*Perhaps not* but possibly a *spigot* is a* faucet* or a *tap*??
Next we could delve into root words and learn if there are any connections between clevises and cleavage. 
Perhaps we could use a clevis to cleave between two spigots?
Toodleoo!
Ron Hebbard.


----------



## egilson1

I tend to like Bill's answer, that a shackle is a clevis but not all clevises are shackles. you'll tend to find that most non-shackle clevises are designed for linear loading along their major axis. That's not to say there are not shackles that are also only designed for linear loads.


----------



## BillConnerFASTC

gafftaper said:


> This started out in rigging, but somewhere along the way this was moved to become the QOTD.


I thought this was rigging. If I answered QOD I apologize.


----------



## dvsDave

BillConnerFASTC said:


> I thought this was rigging. If I answered QOD I apologize.



No worries, Ron had asked me to post this on QoTD but I had asked for a definitive answer first. Turns out that wasnt as clear cut as we thought, so it was posted in rigging. Eventually, we moved it over to QoTD, but more.for discussion reasons.


----------



## BillConnerFASTC

If you Google "shackle" and "clevis" and select "images", I think the difference is graphically clear. Whether a clevis is a bent flat bar around a board secured with a pin, two parallel "tangs" or plates with a pin, or a shackle like design at the end of a threaded rod - a clevis end on a turnbuckle - it seems clear. Maybe wishy washy but a clevis seems to be used for attachment, and a shackle is simply a connector or link. Clevises are used in tension and compression, shackles seem only useful in tension. And while a shackle may "bend" a little, a clevis may purposefully be designed to pivot at the pin.

At least in the good old US of A. North of the border all bets are off.


----------



## epimetheus

In my industry, high voltage substations, we use clevis (not sure what the plural is, clevi?) and shackles for transmission line hardware. Comparing the hardware we use, I would say the a clevis has parallel "arms", where as a shackle has rounded "arms". See this page. Then there's also a Y-clevis...

IMO (I'm electrical, not civil/strucural/mechanical), a clevis would be used for inline forces only, where as a shackle would be more tolerant of off angle forces, as others have said above.










Untitled



__ epimetheus
__ Jun 30, 2017


----------



## Amiers

I didn't feel like getting up in the middle of the night to shoot this so I waited til this morning. 




We just call it a hookup for our tractor but I guess it has a real name 'clevis'. For those interested this is our spreader hookup. The ridden wagons and hay wagons have the same hookup as well.


----------



## RonHebbard

BillConnerFASTC said:


> At least in the good old US of A. North of the border all bets are off.


Border? Do we still have one?? Hasn't the Donald merged us yet???
Toodleoo!
Ron Hebbard.


----------



## Van

I thought Clevis was just another term for 'decolletage'.


----------



## BillConnerFASTC

epimetheus said:


> In my industry, high voltage substations, we use clevis (not sure what the plural is, clevi?) and shackles for transmission line hardware. Comparing the hardware we use, I would say the a clevis has parallel "arms", where as a shackle has rounded "arms". See this page. Then there's also a Y-clevis...
> 
> IMO (I'm electrical, not civil/strucural/mechanical), a clevis would be used for inline forces only, where as a shackle would be more tolerant of off angle forces, as others have said above.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Untitled
> 
> 
> 
> __ epimetheus
> __ Jun 30, 2017


 In your diagram, everything with the name "clevis" has an anchor point. I still think more than inline or off angle that compression and tension is more important. A shackle would never have a compressive force, and never be anchored to a pole or structure. Those clevises and "ball" devices re very specific to your trade - ball and socket insulators.


----------



## BillConnerFASTC

Amiers said:


> I didn't feel like getting up in the middle of the night to shoot this so I waited til this morning.
> View attachment 14957
> 
> 
> We just call it a hookup for our tractor but I guess it has a real name 'clevis'. For those interested this is our spreader hookup. The ridden wagons and hay wagons have the same hookup as well.



And you can back up with that, right, so the clevis is in compression?

The unused "ring" to the right - wouldn't that be for a pintel hitch?


----------



## Amiers

Correct you can backup with it and it will do pretty much a 90. Not recommended as you could snap the PTO but things have happened where it's been close.

What ring to the right?

The ball in the bottom left is part of our three point hitch for our chopper and grader.


----------



## RonHebbard

Van said:


> I thought Clevis was just another term for 'decolletage'.


Maybe Clevii are Levi's for Clever people?
Not being clever, I wouldn't know.
Toodleoo!
Ron Hebbard.


----------



## BillConnerFASTC

Amiers said:


> Correct you can backup with it and it will do pretty much a 90. Not recommended as you could snap the PTO but things have happened where it's been close.
> 
> What ring to the right?
> 
> The ball in the bottom left is part of our three point hitch for our chopper and grader.



I did mena lower left but I get it now. I did once upon a time, when Toodles was a wee boy, work on a farm, drove tractors, shoveled BFM (bovine fecal matter), etc. Some things don't change much.


----------



## Amiers

I'll get a picture of the full rear end for ya after the show. 

Working here I've learned to drive the equipment but try to not get into dealing with the poop stuff. Gotta draw a line somewhere.


----------



## RonHebbard

BillConnerFASTC said:


> I did once upon a time work on a farm, drove tractors, shoveled BFM (Bovine Fecal Matter), etc. *Some things don't change much.*


Perhaps the major change is you get paid more for it?
Toodleoo!
Ron Hebbard.


----------



## Van

On a more serious note:
*Etymology[edit]*

First attested in 1590s. Origin unknown; probably derived from the verb "to cleave". If so, the word ultimately may stem from Scandinavian: compare Old Norse _kljufa_ (to split).
*Noun[edit]*



Wikipedia has an article on:
*Clevis fastener
clevis* (_plural_ *clevises*)


clevis

A U-shaped coupling having holes at each end, through which a bolt is run; used especially to fit attachments to a tractor or other vehicle as it allows a degree of rotation about the bolt.


----------



## RonHebbard

Amiers said:


> I'll get a picture of the full rear end for ya after the show.
> 
> Working here I've learned to drive the equipment but try to not get into dealing with *the poop stuff*. Gotta draw a line somewhere.


You can get into more than enough "poop" right here on CB.
Toodleoo!
Ron Hebbard.


----------



## Amiers

BillConnerFASTC said:


> I did mena lower left but I get it now. I did once upon a time, when Toodles was a wee boy, work on a farm, drove tractors, shoveled BFM (bovine fecal matter), etc. Some things don't change much.



Here ya go.


----------



## BillConnerFASTC

Yeah - I got it as soon as you said what it was for. I think I called it a three point hitch. Mowing machine - in antique terms at least. Something like this with a sickle bar:


----------



## Amiers

BillConnerFASTC said:


> Yeah - I got it as soon as you said what it was for. I think I called it a three point hitch. Mowing machine - in antique terms at least. Something like this with a sickle bar:



Showing your age there Bill, with that 55 Ford and a simple sickle hook up :shock::shock::shock:


----------



## Blacksheep0317

I agree with @porkchop . Shackles are an in-line connection device, with no fixation. A clevis refers to an anchoring device.

So yes, a shackle can be made into a clevis, but a clevis cannot be used as a shackle. 

Shackle goes between things, clevis is the thing.


----------



## sloop

A clevis is a pin you can lock in place. A shackle has a clevis. A clevis is NOT a shackle, but a shackle has to have a clevis pin to work. I sail, we use a LOT of clevis's to attach stays etc on the boats, often at the end of a turnbuckle.


----------



## BillConnerFASTC

sloop said:


> A clevis is a pin you can lock in place. A shackle has a clevis. A clevis is NOT a shackle, but a shackle has to have a clevis pin to work. I sail, we use a LOT of clevis's to attach stays etc on the boats, often at the end of a turnbuckle.


I think that is a local or nautical only application. Clevises have clevis pins and shackles have shackle pins.


----------



## Van

Gotta go with Bill. The etymology of the word 'Clevis' is from 'Cleave' to make a split through. A clevis pin, ties together the sides of the Cleaved are or, the clevis.

Edit: Oh, except the pin in a shackle is, technically, still referred to as a "clevis pin" as it spans the Cleave.


----------



## egilson1

sloop said:


> A clevis is a pin you can lock in place. A shackle has a clevis. A clevis is NOT a shackle, but a shackle has to have a clevis pin to work. I sail, we use a LOT of clevis's to attach stays etc on the boats, often at the end of a turnbuckle.



Having also grown up building and racing sailboats, I would respectfully disagree that it's just the pin. You can look though a West Marines catalog and find many U shaped objects called a Clevis, with and without a Clevis Pin.


----------



## sloop

egilson1 said:


> Having also grown up building and racing sailboats, I would respectfully disagree that it's just the pin. You can look though a West Marines catalog and find many U shaped objects called a Clevis, with and without a Clevis Pin.



I stand corrected. A simple search.. clevis----"a U-shaped or forked metal connector within which another part can be fastened by means of a bolt or pin passing through the ends of the connector."


----------



## curtis73

I grew up on a farm, so we used different terms. Here is the actual breakdown on the most universal terms I have found:

The Shackle is the whole thing and applies to a variety of terms, including a verb (I shackled this to that) or a noun referring to any one of several means of attaching two things together via some form of yoke or basket and some form of retaining pin or bolt. At it's most base level, the Clevis is the retaining element, the Basket or Yoke is the connector, and the Shackle is the whole kit.

When attaching an implement to a tractor with the typical method, you slide the yoke or basket over the drawbar and insert a Clevis pin which makes the whole apparatus a shackle.

So to be plain, the Shackle is the method, and the item pictured below (in theater) is usually called a Shackle. Much like calling a 3/8" grade 8 bolt a "fastener." It's a bit of a generic name. The real name for what is pictured below first is a Clevis-and-yoke Shackle. In truth, a quicklink (threaded chain link) is a "shackle," but not rated for rigging. In theater terms, calling the whole thing a Clevis is less accurate since the clevis is just the pin part.

Things get tricky when you talk about threaded versions where the basket has either male or female threads... for instance, a turnbuckle like the second picture has what appears to be a Clevis Shackle on the end, but because it is a threaded fastener, they are commonly referred to as "jaws." The retaining pin is still called a Clevis and can be either a slip-fit pin with a cotter key, wire, or other retention device, a bolt and nut, or one side of the jaw may be threaded and the clevis itself is threaded. In that order, they are usually called Clevis Pin, Clevis bolt, or clevis screw.


----------



## BillConnerFASTC

What you say may be true on a farm, but in my experience, not so much on a stage, and will just confuse communication. 

I believe even on a farm the clevis is not the pin or bolt as your second illustration indicates. The pin can be called a clevis pin, but not just a clevis. 

Everyone in rigging understands what a jaw-jaw turnbuckle is, or a an eye-jaw. Call it a clevis clevis turnbuckle (or shackle shackle turnbuckle) and I think you'll just confuse the situation.

And unlike the clevis or "U-shaped coupling having holes at each end", a shackle (and a turnbuckle) is useless for compressive loads. I've had good luck backing a load on a wagon attached to a tractor with clevis and pin, not such good luck pushing a load with a lift line with turnbuckle and shackle.

On the other hand, google clevis on a farm and I get:



So maybe no difference to some in a multicultural world. (farm hands and stage hands?)


----------



## BillConnerFASTC

And this, called a twisted clevis. Notice which part is twisted. Not the pin...


----------



## BillConnerFASTC

And here's a farmers bulletin board on the same issue - sorta - with a few tangents. Its starts a little slow but I encourage you to keep reading.

https://talk.newagtalk.com/forums/thread-view.asp?tid=223642&DisplayType=flat

I wonder if they read this CB thread is they would laugh as much as I did reading theirs....


----------



## BillConnerFASTC

I apologize to Curtis as what he suggest does seem suitable for agriculture. Take a look at this data sheet but the key part is a quote from a DOE publication:

"Shackles are primarily used in construction, rigging and lifting. A clevis is used in less demanding applications such as farming and towing."

So both right - just don't use a (farm) clevis in my stage rigging - shackles only - and specifically anchor shackles with screw pins please.


----------



## Ravenbar

Honestly, for something I'd be visually able to inspect while in use(and with load ratings), I'd prefer a twisted clevis, as it's got a built in weakness / obvious visual indicator of deformation (twist wouldn't be at 90deg if any deformation.) 

I rarely do any real rigging as the 1 show I do a year, I'm only handling lighting. I have been known to look at what their doing, say no, and hand over the 5000lb BS carabiner I use for my keys(I had no input, but they were suspending a student a couple feet over a bed... using hardware store grade, unrated hardware. I've seen those carabiners open up before...)


gafftaper said:


> Well you have me interested Toodles. I thought Clevis was just an old term for Shackle, possibly a brand name from back in the day.
> 
> @porkchop would be another good person to call out.



That's what I've always understood...

What Rigger? said:


> Well, in my world, this has always been a clevis. But that doesn't stop the current employer from publishing internal documents calling a clevis pin a "detent pin". And then a shackle is a shackle.



The detent pin in that picture is a bolt. a Detent pin has a spring powered ball bearing in the side at the end to retain it... Think of the socket retaining bump on a ratchet, that's a ball detent.


----------

