Washers for link bolts?

[RunningProblem]

Does everyone use washers for 3 link and 4 link bolts or are the link brackets acting like a washer? I’ve honestly not pid any reaal attention to it ever and my guess is everyone runs a washer on both sides.

 

[Dookey]

I always bought my brackets with the bolt hole too small and drilled them out to my exact bolt dimension. I bought weld washers the same way to beef up the brackets and welded them in place. Always bought a bolt that was too long so the bolt shoulder sat in both brackets. Then cut the end of the bolt off with enough threads sticking out the nut. And loctite.

 

[RunningProblem]

I never thought about weld washer.

 

[CarterKraft]

I always bought my brackets with the bolt hole too small and drilled them out to my exact bolt dimension. I bought weld washers the same way to beef up the brackets and welded them in place. Always bought a bolt that was too long so the bolt shoulder sat in both brackets. Then cut the end of the bolt off with enough threads sticking out the nut. And loctite.

All this the right way.
Also I am fond of CAT thick hardened washers and CAT bolts torqued to spec.
Shitty washers are worse than no washer IMO.

 

[RunningProblem]

What is so special about CAT 9/16 vs grade 8 or 10.9 metric equivalents?

 

[Bray D]

At the end of the day, torque your fasteners, recheck often, and your shit will stay together. Everything else is splitting hairs. Since the question was asked, I'll get out my hair splitter

I use hardened washers on the bolt and nut side. Most bolts have a radius under the head. The 'loose' washer will self locate and eliminate the potential for deforming that radius and creating a stress concentration under the bolt head.

Washers are harder than your mild steel brackets. It influences the coefficient of friction between mating faces that slide against each other as you're applying torque, changing your fastener preload as a result.

Those hardened washers will also distribute the clamp load better onto your soft ass bracket steel, reducing the likelihood for deformation once it's torqued. If your bracket has local deformation during use, you lose clamp load.

Size the fastener so the clamp load once torqued does the work, then make sure it's always torqued. If things go sideways and you DO lose torque, or your fastener was undersized and couldn't keep things from moving once torqued, Dookey's method of doubling up the bracket thickness with weld washers, ensuring close clearance with the bolt, and maximizing bolt diameter within the joint will be putting your best foot forward against catastrophic failure.

 

[RunningProblem]

So using a 2 5/8 wide joint, with 1/4” thick material using Dookey ’s method is probably going to use a 4” bolt so the shoulder goes the whole way through both sides of the bracket. Cut extra threads into the shoulder exposed past the bracket and cut the whole bolt to whatever length is a few threads past the nut. Correct?


Torque to 100 ft pounds, or more?
First generic bolt torque chart I found for grade 8 hardware.

https://www.aftfasteners.com/content/Technical%20Guides/ASTM%20A354_Torque%20Values%20Pg%205.pdf

 

[Bray D]

I wouldn't be cutting fresh threads into fasteners. As far as the stack up goes, you only 'need' full shoulder diameter to the interface of the joint and the bracket - that's your shear plane.

1/4" weld washer + 1/4" bracket + 2-5/8 joint = 3-1/8" shoulder length minimum. Add another 1/4" for your nut side bracket plate and another 1/4" for your other weld washer and your absolute max shoulder length would be 3-5/8".

Looks like a 5" bolt will put you right at your 3-5/8" shoulder length. If you find that's a touch too long to get a nut on it, add a hardened washer.

Alternatively, a 4.5" bolt will give you right at the calculated minimum shoulder length and would ensure 100% that you would be able to get a nut on it without cutting threads or adding another washer. Decisions decisions.

This is my go-to torque chart. My machine design book says 'when in doubt, assume K = .20 for dry threads.' (paraphrased). I assume you have at least 9/16" link bolts, which will run you up to around 150ft lbs for a Grade 8 fastener.

Fastenal Master Torque Chart

 

[crazybluerider]

I actually torque my link bolts. I think most people are far under correct torque, the correct torque for the 3/4 and 5/8 bolt a lot of us are running on our hiems isn't even achievable with a typical 1/2 ratchet in the 9" handle flavor and even feels crazy tight with my 2' handled torque wrench. Same goes for link lock nuts, everyone talks about link nuts coming loose all the time, proper torque for a 1 1/4" nut is well over 1000 ft lbs. Get the longest wrench you can and you still wont be able to get them into spec without some kind of mechanical advantage, I've had OK luck with beating the fuck out of the wrench with a hammer but I'm sure they're still not actually tight enough.

 

[white-rhino]

I wouldn't be cutting fresh threads into fasteners. As far as the stack up goes, you only 'need' full shoulder diameter to the interface of the joint and the bracket - that's your shear plane.

1/4" weld washer + 1/4" bracket + 2-5/8 joint = 3-1/8" shoulder length minimum. Add another 1/4" for your nut side bracket plate and another 1/4" for your other weld washer and your absolute max shoulder length would be 3-5/8".

Looks like a 5" bolt will put you right at your 3-5/8" shoulder length. If you find that's a touch too long to get a nut on it, add a hardened washer.

Alternatively, a 4.5" bolt will give you right at the calculated minimum shoulder length and would ensure 100% that you would be able to get a nut on it without cutting threads or adding another washer. Decisions decisions.

This is my go-to torque chart. My machine design book says 'when in doubt, assume K = .20 for dry threads.' (paraphrased). I assume you have at least 9/16" link bolts, which will run you up to around 150ft lbs for a Grade 8 fastener.

Fastenal Master Torque Chart

^^^^^^ This right here all the way. I bought a rig and a month after I had it, a link bolt failure. Turned out the shoulder/ thread transition was right in line with where the alignment spacer goes into the heim joint. The fatigue lines in the bolt showed that it had been flexing and failing for a long time. I've also added washers to either fix a rounded out hole or to eliminate any slop.

 

[arse_sidewards]

The OEMs have no problems using flanged bolts and nuts that are tack welded to the brackets. That works fine despite the floppy wet noodle brackets they build shit with so that's what I copy.

 

[Weasel]

What is so special about CAT 9/16 vs grade 8 or 10.9 metric equivalents?

They are consistent and of a better known quality in my mind. Seem like normal sotre bought stuff has been iffy the last few years. And the rated hardened items are more then getting them from CAT. The coatings are great and typically run closer tolerance then hardware store, 0.1" or thicker.

 

[CarterKraft]

What is so special about CAT 9/16 vs grade 8 or 10.9 metric equivalents?

They are consistent and of a better known quality in my mind. Seem like normal sotre bought stuff has been iffy the last few years. And the rated hardened items are more then getting them from CAT. The coatings are great and typically run closer tolerance then hardware store, 0.1" or thicker.

Exactly. Hardware store bolts are not good at all IMO, they are priced to fit a market not a spec.
Inch size CAT bolts have thicker heads and that is a really awesome feature you didn't realize you needed.
Nuts are marked for grade, and made from fine grain steel, quality checked per batch, one failed test bolt in a batch will scrap the batch vs a % of failure in general hardware.

It's kind of hard to explain but once you use quality hardware, bolts, washers and nuts you realize how shitty the stuff you were using is.
Hammering on m10 and m8 bolts with a really strong impact daily and never breaking one under normal conditions is an example.

CAT bolts are easy to get for most people, have a wide selection and can be bought per bolt not per 50 or whatever quantity Fastenal can get.
I you need anything specific post up what you are looking for and I'll see what I can find.

This is great resource for hardware but there is more to choose from, but it's not readily available in a online catalog.
Caterpillar 2019 One Safe Source

Bolts start on page 468.
This is that page and describes the readily available offerings.

 

[RunningProblem]

I actually have a CAT dealership in town. I always thought you had to be a professional/dealer to buy from them.

 

[bdkw1]

I wouldn't be cutting fresh threads into fasteners. As far as the stack up goes, you only 'need' full shoulder diameter to the interface of the joint and the bracket - that's your shear plane.

1/4" weld washer + 1/4" bracket + 2-5/8 joint = 3-1/8" shoulder length minimum. Add another 1/4" for your nut side bracket plate and another 1/4" for your other weld washer and your absolute max shoulder length would be 3-5/8".

Looks like a 5" bolt will put you right at your 3-5/8" shoulder length. If you find that's a touch too long to get a nut on it, add a hardened washer.

Alternatively, a 4.5" bolt will give you right at the calculated minimum shoulder length and would ensure 100% that you would be able to get a nut on it without cutting threads or adding another washer. Decisions decisions.

This is my go-to torque chart. My machine design book says 'when in doubt, assume K = .20 for dry threads.' (paraphrased). I assume you have at least 9/16" link bolts, which will run you up to around 150ft lbs for a Grade 8 fastener.

Fastenal Master Torque Chart

Bolts from MMC don't always match the drawings as far as how much thread they have. They source for several vendors and things vary between them.

I prefer to use allen bolts in critical locations if I am paying for them. If somebody else is paying, aircraft bolts with the proper grip length.

 

[CarterKraft]

Bolts from MMC don't always match the drawings as far as how much thread they have. They source for several vendors and things vary between them.

I prefer to use allen bolts in critical locations if I am paying for them. If somebody else is paying, aircraft bolts with the proper grip length.

The only thing about socket head cap screws is the heads will pop off if abused. The thickness of the head at the bottom of the socket makes them very thin in that area. The only bolts I have had do that are socket head cap screws.

 

[CarterKraft]

The only thing about socket head cap screws is the heads will pop off if abused. The thickness of the head at the bottom of the socket makes them very thin in that area. The only bolts I have had do that are socket head cap screws.

Here is a recent example.
Not sure the actual reason this happens but it only happens to me on socket head screws.

 

[bdkw1]

The only thing about socket head cap screws is the heads will pop off if abused. The thickness of the head at the bottom of the socket makes them very thin in that area. The only bolts I have had do that are socket head cap screws.

The only bolts I have had fail on a race car were both F911's. The heads popped off both. Replaced with allens and no more issues. I have yet to have an allen fail.

 

[bdkw1]

Here is a recent example.
Not sure the actual reason this happens but it only happens to me on socket head screws.

That looks like someone got carried away with the torque specs.

 

[Weasel]

I actually have a CAT dealership in town. I always thought you had to be a professional/dealer to buy from them.

nope that's the amazing part. If I need a 5/16-24 @ 3.75" long and it's not in stock it will be there next day 99% of the time at no cost. All for a $1.37 bolt.

And this includes Saturday delivery of which they are usually open to 2 or 3pm.

The ship enough freight daily that it doesn't matter how much you get, it's included.

They always ask me what I'm building now.

 

[CarterKraft]

nope that's the amazing part. If I need a 5/16-24 @ 3.75" long and it's not in stock it will be there next day 99% of the time at no cost. All for a $1.37 bolt.

And this includes Saturday delivery of which they are usually open to 2 or 3pm.

The ship enough freight daily that it doesn't matter how much you get, it's included.

They always ask me what I'm building now.

And I didn't say it but I work for a CAT dealer, why I am biased..
It doesn't really matter where you get bolts from but they need to be good bolts in places that matter, link bolts would fall in that category.

 

[CarterKraft]

That looks like someone got carried away with the torque specs.

I have had that same failure in a timing gear idler shaft inside the front cover of small 4 cylinder diesel engines. That was actually a recall and they had to be replaced in every tractor we sold.

Another application is the spring caps of a hydraulic drive motor on medium size excavators, they pop the heads off with some age/hours.

Again I don't know why it happens but it only happens to me with socket head screws.

 

[RunningProblem]

So much great information here. I’ll have to look into some weld washers and CAT bolts since the sound so amazing. Fastenall seemed to be about $5.50 for a grade 8 4-5” 9/16-18 bolt.

 

[RunningProblem]

CAT

This is great resource for hardware but there is more to choose from, but it's not readily available in a online catalog.
Caterpillar 2019 One Safe Source

Bolts start on page 468.
This is that page and describes the readily available offerings.

Is there really no 9/16 bolts at CAT?

 

[CarterKraft]

9/16" is the odd duck.

I found a 12 point bolt with the right specs but its a con rod cap bolt from a giant v12 and they are $43 each because they are so high performance in $$$$ engines.

 

[Weasel]

Is there really no 9/16 bolts at CAT?

Yes that is a stupid size and you should be using 5/8"

But seriously, that size is not all that common.

I have even gone to check to see what CAT has when picking rod end sizes.

I'll upload all the reference docs I have for CAT.

 

[RunningProblem]

So to continue this....

What is the problem with having the threaded end of the bolt in the middle of the bracket? I have a 4" bolt and a 4 1/2" bolt. The 4 1/2" bolt would need three washers stacked up to fill the space between the end of the threads and the bracket. The 4" bolt has the start of the threads in the middle of the bracket, so about 1/8". Is this going to kill a bus full of nuns, or do people do this type of stuff all the time and survive?


Better photo 1 or better photo 2?

EDIT: This is for the track bar.

 

[arse_sidewards]

So to continue this....

What is the problem with having the threaded end of the bolt in the middle of the bracket?

Reduced minor diameter where the threads are and threads chewing up a bracket hole.

Not really shit you need to worry about unless you're trying to design something to be within an inch of its life to save weight or you're trying to get the most while working within the limitations of factory brackets and bolt sizes.

 

[white-rhino]

So to continue this....

What is the problem with having the threaded end of the bolt in the middle of the bracket? I have a 4" bolt and a 4 1/2" bolt. The 4 1/2" bolt would need three washers stacked up to fill the space between the end of the threads and the bracket. The 4" bolt has the start of the threads in the middle of the bracket, so about 1/8". Is this going to kill a bus full of nuns, or do people do this type of stuff all the time and survive?


Better photo 1 or better photo 2?

EDIT: This is for the track bar.

Anywhere there is an opportunity to flex, its' a bad idea. see post #10 - real world example.

 

[Wisconsinite]

Anywhere there is an opportunity to flex, its' a bad idea. see post #10 - real world example.

In a perfect world with proper torque, it shouldn't matter, right?