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View Full Version : Afraid......! Is my tripod bolt going to break!?



paradoxbox
4-Sep-2009, 09:21
Howdy all. I just got my first large format camera yesterday and it's a lovely unit. It's a big Wista M450 monorail view camera. It's heavy, at least 10 or so lbs (5kg), maybe a little more.

I have a nice Hakuba 503MX carbon fiber tripod with the original pan head which seems to be good enough for me, the camera doesn't shake on the tripod unless I deliberately touch it.

But I am worried about moving the camera with it mounted to the tripod. The tripod has a standard 1/4 inch bolt as is found on every normal camera in the world. Is this bolt going to be strong enough to withstand the weight of such a heavy camera? Has anyone here broken a tripod bolt while carrying their tripod over their shoulder?

Worries me as this camera's in pristine condition, but taking it all down every time I need to move it rather than just putting it over my shoulder is a bit of a pain.

photographs42
4-Sep-2009, 09:26
My 5x7 Technika weights around 12 lbs and I carry it over my shoulder all the time with no problem.
Jerome

Mark Woods
4-Sep-2009, 09:26
If you have a stainless steel bolt made for the purpose you should be fine. The manufacturer is the one who made the 1/4-20 hole. If there is an insert, take it out and use the 3/8-16 bolt. It should be more than enough.

BrianShaw
4-Sep-2009, 10:40
I trust the experience of our colleagues... but I don't and I wouldn't no matter how much anyone says they do. I carry my camera on tripod in an upright position (which means that I don't carry it very far) or cradled like a baby so my arms are supporting the weight of both the camera and tripod (which also meas that I don't carry it very far).

Jeffrey Sipress
4-Sep-2009, 10:44
Those bolts are stronger than they look. But I do like the idea of changing to a 3/8-16 stud. I carry my cameras over my shoulder a lot, but I always employ a lanyard tether from the camera to the head incase of mechanical failure. Ever time I mount my camera (4x5 or 1Ds111) I clip on that lanyard to a loop i added to the camera.

Bill_1856
4-Sep-2009, 11:08
I'm sure many of us carry our cameras that way, but I think that it's tempting fate.

Bruce Watson
4-Sep-2009, 11:11
Is this bolt going to be strong enough to withstand the weight of such a heavy camera?

Good grief. You really think you can break a 1/4 - 20 bolt with a 5 Kg camera? This you can easily prove to yourself. Buy a replacement bolt, put it in a vice, and wale away at it with a hammer. If you can't break it that way, one would think that something as small and light as a camera isn't going to have much of an effect, yes?

Unless the bolt is defective (which happens, if rarely) it's probably several orders of magnitude overkill for your purposes. IOW, you could probably destroy the tripod and the camera and leave that bolt still looking new.

The reason it's as big as it is, is for easy handling by human hands. Doesn't have anything to do with required strength.

Not that I recommend doing the "shoulder walk" with a camera. Too many bad things can happen -- you can easily trash a lens with a tree branch or a swinging shutter release, you can turn a corner fast and bash the camera into a tree truck, you can become unbalanced, slip and fall, etc., etc., etc.

But if the camera gets trashed, it's not likely going to be due to that bolt.

Duane Polcou
4-Sep-2009, 11:25
"Ansel lugging his camera by the sea"

Photo by David Hume Kennerly for Time Magazine, September 3, 1979.

sun of sand
5-Sep-2009, 19:30
riding in car with you must be the most stressful event of most lives lol
OMG CAN THESE TIRES POP?
OMG CAN THESE
HAVE YOU CHECKED YOUR RIVETS
WHEN WAS THE LAST TIME
I'm making this into a hit episode, too

Mike1234
5-Sep-2009, 20:42
I consider this a valid question/concern. It should be fine... just don't go swinging it around as you would a baseball bat. :)

Preston
6-Sep-2009, 05:48
If you can use a 3/8 in diameter bolt, that certainly wouldprovid greater insurance. However, unless you're using the setup as a hammer, the 1/4-twenty will be quite strong enough.

I agree, carrying the camera/tripod over the shoulder without a security measure is tempting fate.

-Preston

paulr
6-Sep-2009, 07:41
Good grief. You really think you can break a 1/4 - 20 bolt with a 5 Kg camera?

Not likely, but not impossible. It's not like the camera by itself will overwhelm the bolt's tensile strength. But the camera mount gives the mass of the camera a good bit of leverage on its attachment point, and the force can be delivered at least in part as torsion ... which will amplify the stresses on one side of the bold or another.

This still won't be enough to break the bolt, but over months or years you have the issue of fatigue. How many of those stress cycles can a 1/4" bolt take? Depends on the quality of the bolt, and many other factors. Its lifespan might be centuries, or just a few years.

The real issue is that you have a big investment trusted to a single bolt. There's no redundancy ... a situation that makes engineers cringe. A bolt rated at a million pounds could be deffective or damaged. When I rock climb and find a bolted anchor, I clip into at least two bolts. They may be 1/2" expansion bolts rated at over 30KN each. No way either one could fail under the best of circumstances. But I have no way of knowing haw good the circumstances actually are, so I get peace of mind from redundancy.

Without that option on a tripod, I might go for the bigger bolt!

Bill_1856
6-Sep-2009, 08:51
The problem isn't so much the bolt breaking, but the effect on your camera's mounting plate. There's not just the force of the bolt holding it down, but the leveraged force on the camera plate from its weight times the length of the mounting platform. I'm sure that most metal cameras can stand it without any deformation, but if it's a wooden camera with a small metal mounting plate it might damage it by loosening it from the wood frame.

GPS
6-Sep-2009, 09:29
Not likely, but not impossible. It's not like the camera by itself will overwhelm the bolt's tensile strength. But the camera mount gives the mass of the camera a good bit of leverage on its attachment point, and the force can be delivered at least in part as torsion ... which will amplify the stresses on one side of the bold or another.

This still won't be enough to break the bolt, but over months or years you have the issue of fatigue. How many of those stress cycles can a 1/4" bolt take? Depends on the quality of the bolt, and many other factors. Its lifespan might be centuries, or just a few years.

..!

Your argumentation is of the "ad absurdum" kind and technically incorrect. Bruce is right.
How many times do you think the bolt will be under the said "cycles"? Will he run with the camera day and night on mountains? Or will he take it 2x per week for 1hr each time? To have some "cycle" to speak about you would need to run with the camera for years and years on the go - with the 5kg camera and some occasional peak of tension you would kill yourself before the "cycle" (occasional use is no cycle, technically speaking) kills the bolt...:)

paradoxbox
6-Sep-2009, 09:37
this is exactly what i'm worried about.

carrying it around on your shoulder puts strong loads on a very small part of the bolt over and over and over again. eventually it stretches then eventually metal fatigue takes over and the bolt breaks. i've read of it happening on the internet but don't know how much credibility there is to it.

anyway mostly i'm just concerned because of the weight, i'm new to cameras this heavy. with the camera bouncing up and down on your shoulder while you walk the actual force put on one small area of the bolt can probably reach hundreds or thousands of pounds. i don't think i trust the stock bolt with that much horizontal weight. i think i'll replace the bolt with something thicker..!


Not likely, but not impossible. It's not like the camera by itself will overwhelm the bolt's tensile strength. But the camera mount gives the mass of the camera a good bit of leverage on its attachment point, and the force can be delivered at least in part as torsion ... which will amplify the stresses on one side of the bold or another.

This still won't be enough to break the bolt, but over months or years you have the issue of fatigue. How many of those stress cycles can a 1/4" bolt take? Depends on the quality of the bolt, and many other factors. Its lifespan might be centuries, or just a few years.

The real issue is that you have a big investment trusted to a single bolt. There's no redundancy ... a situation that makes engineers cringe. A bolt rated at a million pounds could be deffective or damaged. When I rock climb and find a bolted anchor, I clip into at least two bolts. They may be 1/2" expansion bolts rated at over 30KN each. No way either one could fail under the best of circumstances. But I have no way of knowing haw good the circumstances actually are, so I get peace of mind from redundancy.

Without that option on a tripod, I might go for the bigger bolt!

Mike1234
6-Sep-2009, 09:41
As others have said... it's unlikely the 1/4" bolt will break unless you mistreat it. That stated, 3/8" bolts tend to give a bit more rigidity for heavy cameras with lots of bellows draw. It might be worth modification for use with a heavy 4x5 monorail. Just my opinion, of course.

Don't ever carry a heavy monorail attached to the tripod slung over your shoulder.

Bruce Watson
6-Sep-2009, 10:32
Not likely, but not impossible. It's not like the camera by itself will overwhelm the bolt's tensile strength. But the camera mount gives the mass of the camera a good bit of leverage on its attachment point, and the force can be delivered at least in part as torsion ... which will amplify the stresses on one side of the bold or another.

This still won't be enough to break the bolt, but over months or years you have the issue of fatigue. How many of those stress cycles can a 1/4" bolt take? Depends on the quality of the bolt, and many other factors. Its lifespan might be centuries, or just a few years.

The real issue is that you have a big investment trusted to a single bolt. There's no redundancy ... a situation that makes engineers cringe.

I don't know about you, but I am an engineer. Mechanical. And the lack of redundancy in this case doesn't even begin to make me cringe. Come on! This isn't life or death. It's hardly a risk at all. The only real risk here is operator error. The human will drop the system, run it into something, or find some other way to destroy it. Unless the bolt is clearly and obviously defective, the bolt will not be a fault. Really. I'm not kidding.

I've built a lot of specialty machine tools in my time. I can tell you that the lifetime of all but the crappiest steel bolts under the minimal stress (and I do mean minimal) this application can apply, is an infinite number of cycles. Infinite. It will not fatigue. It's possible that you could induce stress corrosion cracking, but I doubt many people would know how, and because the stress is so low, the corrosion would have to be obvious and noticeable, so that's not likely either.

This ain't rock climbing Paul. The level of risk isn't in the same order of magnitude. Or even within several orders of magnitude.

It amazes me that people will obsess over something like this and think nothing of driving down the interstate at 100 Kph eating a donut, talking on the cell phone, and spend half their time twisted around facing the back seat while arguing with their kid, surrounded by hundreds of other people also hurtling down the road doing the same things at the same speeds. Talk about risk!

This is a simple matter of perspective, and not having it. You've got a much better chance of damaging the camera during the car trip out or back than you do while you are there with the camera bolted to the tripod. And if you do manage to damage the camera while it's bolted to the tripod, it won't be because of the bolt. Really.

Get a grip guys.

eli
6-Sep-2009, 10:44
It should be fine as is but if you're really worried, buy aircraft grade steel bolts as replacements; I doubt you find higher quality hardware anywhere.

Eli

Bruce Watson
6-Sep-2009, 11:07
this is exactly what i'm worried about.

carrying it around on your shoulder puts strong loads

Your fears are irrational. And "strong loads"? Compared to the strength of the bolt, the loads you are worried about are negligible.


on a very small part of the bolt over and over and over again. eventually it stretches

It does not. You'll have to exceed the bolt's yield strength to "stretch" it.


then eventually metal fatigue takes over and the bolt breaks.

Oy vey. Go find someone to talk to you about strength of materials. There are many books out there just about what fatigue is and how it works. Suffice it to say, you are in little danger of metal fatigue, and then only if the metal in question is an exotic alloy and your loads large enough. Your meager loads will let most steels cycle infinitely without any fatigue at all.


i've read of it happening on the internet but don't know how much credibility there is to it.

But have you heard about it on AM talk radio? Where there's nothing but the truth, the whole truth, so help me... :D


anyway mostly i'm just concerned because of the weight, i'm new to cameras this heavy. with the camera bouncing up and down on your shoulder while you walk the actual force put on one small area of the bolt can probably reach hundreds or thousands of pounds.

Hundreds or thousands of pounds? And you're worried about a bolt and not your shoulder?

I was one of the guys who lifted and suspended my department head's car for a demonstration. We put it on a platform (more weight), hooked it up with big steel cables (what we had laying around the engineering labs, and more weight) and tied the cables into a common #6 bolt and lifted everything through that (which was serious overkill or he would never have risked his car). Left it eight feet off the ground all day so people could walk under it. Students did this every year when we opened up the school for potential incoming freshmen and their families to visit. Along with many other demos of course.


i don't think i trust the stock bolt with that much horizontal weight. i think i'll replace the bolt with something thicker..!

Your fears are irrational. But just because they are irrational doesn't mean they aren't real to you. So do what you need to do to allay your fears. Else they'll always be on your mind and will thus interfere with your photography.

Aender Brepsom
6-Sep-2009, 11:19
The bolt may not fail, but you could stumble and the camera/tripod combination might hit the ground. I only carry my camera mounted on the tripod in an upright position for a few meters.
With a good quick release system (like Arca Swiss, Really Right Stuff etc.), the camera can be mounted quite quickly and transporting it in the bag is a lot safer.

Some may call me overly cautious, but years ago, I once carried my SLR with a 300mm f2.8 (mounted on the tripod) over my shoulder when it fell off and hit the concrete ground ... Lesson learned the hard way.

Eric Brody
6-Sep-2009, 11:20
The bolt may hold, but your footing may not. Over 20 years ago, I slipped while going downhill while carrying my metal field camera over my shoulder on a very sturdy tripod. The camera stayed on the tripod but hit the ground and bent the frame. Large format is a slow process anyway, I put the camera away when I'm moving any significant distance (long enough that I'd consider hoisting it over my shoulder).

Good luck.

Eric

paulr
7-Sep-2009, 00:59
I don't know about you, but I am an engineer. Mechanical. And the lack of redundancy in this case doesn't even begin to make me cringe.

Hey, I never even considered this question until it came up just now. I've been slinging my camera over my shoulder on a tripod for years and years (no idea actually what size the bolt is, and I've never inspected it).

But the question appealed to the cllimber in me, and it seems reasonable. Not because I think the bolt is likely to break, but because any time there's a lack of redundancy, and fairly high stakes, a bit of overkill makes sense.

Am I paranoid about it? Nope. Do I blame someone else for getting paranoid? Nope.

wclavey
7-Sep-2009, 20:09
Someone needs to fess up to being stupid, so I will... about 3 weekends ago, I was walking on the road through a cemetery where I was photographing with my Shen Hao mounted on the tripod and the Sironar 210mm moounted on the camera - - all assembled and slung up on my shoulder. As I went under some low hanging tree branches, a branch must have caught on the QR lever on the tripod head and the camera and lense came crashing to the road - - but the 1/4" bolt on the tripod QR held! (Just kidding - - had nothing to do with it.) It is an older tripod head that doesn't have the little safety catch on the QR that prevents accidental release.

So while this story is only peripherally related to the 1/4" bolt, it is related to carrying your camera on the tripod over your shoulder. I have been carrying this arrangement for 4-5 years now, and the Mamiya TLRs the same way for 30 more years before that, but I don't think I will get over the sinking feeling of hearing the crash of the camera behind me enough to carry it that way anymore.

I bought new hardwood; I shaped replacements for the broken parts; I have reassembled the camera; and I am sending the lens off to be checked and repaired, if necessary... so I'm back in business... but I decided that the Shen Hao has that leather handle on the top for a reason and I'm going to remove the camera from the tripod and carry it that way from now on.

Wallace_Billingham
8-Sep-2009, 12:19
Someone needs to fess up to being stupid, so I will...

Well in that case, I do a lot of photography of moving water where I set my tripod up in the water sometimes 3-4 feet deep.


I have knocked the tripod over in the water several times but the camera/tripod bolt has been solid each time.

The strangest time was when a 15-18" smallmouth bass came up and lunged against my tripod grabbing at the lever that locks the leg sections when you raise it up and down with his mouth. I was not more than 2 feet away when this happened, and if I did not see it, I would not have believed it. The tripod began to fall over but I was able to snatch the camera by the strap and save it. Of course since I often fish and photograph the same streams at the same time, I tried in vain the rest of the afternoon to cath that fish for dinner but was unable to.

rdenney
8-Sep-2009, 13:55
Here are some real numbers:

The safe tensile working stress of a Grade 2 (read: typical crappy home-center bolt) 1/4"-20 bolt is 55,000 psi. With a stress area of 0.0318 square inches, that's a proof load of 1749 pounds.

How much bending will produce that much tension? If the center of gravity of the camera is 9 inches above the platform (which is about where it might be on my Sinar with the tall tripod adapter, but really much higher than for a field camera, it seems to me), and if the platform is about 0.6" from the bolt to the edge as it is (from memory) with a small Arca-Swiss plate, the weight of the camera might be amplified by a factor of 15 in the worst-case orientation (9 / 0.6). If my camera weighs 10 pounds, it might apply 150 pounds of tensile load on the bolt. Let's say I shake it up and down, resulting in a force of 2G's at the bottom of the shake. That would double that load to 300 pounds.

I would think all that is pretty much worst case. Most cameras are lower, the Arca plate that I use has a wider platform, and I don't think my Sinar weighs as much as 10 pounds. Plus, I don't shake it that much when it's over my shoulder--I'd have to shake my shoulder by the same amount and my legs can cushion load applications a lot better than that.

But we do have to add that load to the clamp load that exists because we tightened the bolt down. That clamp load at maximum tightening torque would be 723 pounds (when tightened to 49 in-lbs while lubricated). There is a lot that goes into clamp load, but I'll take that number as reasonable. That means that the safety margin is nearly 2 to 1. (1749 / (723 + 300) = 1.7).

And that's with crappy hardware-store Grade 2 bolts. The safety margin with Grade 5 bolts (typical bolt on a car) would be 1.9 (and that's if you tighten it to its maximum torque--much higher clamp load than with the Grade 2).

A 3/8"-16 bolt provides a safety margin 2-1/2 times what the 1/4" bolt provides. Many tripod heads and plates use a brass bolt in that size, which is probably no stronger than the cheapest steel bolt.

As for fatigue, the fatigue limit for steel bolts not loaded near their yield point is effectively infinite. Even when loaded close to their yield point, it might be millions of cycles, depending on how its made. Most bolts are stamped and have radiused thread roots that don't crack easily.

So, I think I've addressed all the concerns: The increase in the load from the leverage against the small plate, the shaking, the tall camera, the heavy camera, and the low-grade bolt, tightened to its maximum specification. Still a healthy safety margin. The only 1/4" tripod bolts I've seen that were broken were overtightened using a big wrench.

Rick "also an engineer" Denney

jb7
8-Sep-2009, 14:27
Someone needs to fess up to being stupid, so I will...

A long time ago, I was carrying a rented sinar over my shoulder.
Getting into a lift, I knocked the camera off the door, and the back fell off,
shattering the glass on the tiled floor-

Needless to say, the rest of the camera remained firmly attached...

BrianShaw
8-Sep-2009, 14:40
Rick "also an engineer" Denney

Very interesting! But, I'm still not going to carry my camera while mounted on a tripod slung over my shoulder. ;)

rdenney
8-Sep-2009, 15:10
Very interesting! But, I'm still not going to carry my camera while mounted on a tripod slung over my shoulder. ;)

Everyone does what they are comfortable doing.

I carry my camera that way frequently, but only for short distances. My main limitation is my own clumsiness. The bolt won't break, but that doesn't mean I won't swing the camera into a post.

I was down at Niagara over the weekend, and suddenly the wind shifted and we were getting rained on by blowing mist. I picked up the tripod, threw it over my shoulder, threw the focus cloth over the camera, and ran. I never worried about the bolt:)

Rick "the picture from that spot sucked anyway" Denney

iamjanco
8-Sep-2009, 15:32
I consider this a valid question/concern. It should be fine... just don't go swinging it around as you would a baseball bat. :)

...unless, of course, while you are under the cloth setting up to take pix of those grizzlies in Yellowstone, one of their cousins approach from the south side, looking for a quick meal :eek:

Milton Tierney
8-Sep-2009, 17:04
Iíve carried my 35mm w/ a 600mm 4.5 lens with the same 1/4bolt for 20+ yearsÖÖno problem. I trust the bolt, not me. Iíve lost a camera one time because a bone head (me) didnít take the time to make sure the camera was securely locked on the tripod head. When I carry my LF camera itís for a short distance also. In a open field itís over my shoulder otherwise under my arm covered with a focus cloth or in a bag. The only thing Iíve had break on me are those cheap plastic locking levers for the tripod legs.

Michael Lloyd
15-Sep-2009, 18:13
I carry a 600mm f4 and 1DMK3 with an RRS angle bracket... probably 15 - 17 pounds quick release clamped in an RRS bracket on an RRS ballhead all mounted to a Gitzo carbon fiber tripod over my shoulder all the time. I have the camera and lens strap through my hand.. insurance... but I've never had a problem...

venchka
16-Sep-2009, 07:40
The connecting hardware may be fine. What has happened is the quick release plate releasing when it shouldn't. Double check that connection frequently. The back up lanyard sounds like a perfect "belt & braces" solution.

Dave Hally
17-Sep-2009, 10:21
I think that you don't have anything to worry about. Mycamera is about 6 lbs, without the lens. I have carried it for miles in rough terrain, Had it knocked over by wind, pulled over by a digital back tether, hit by a car backing out at Point Lobos. Th only damage was to the camera (front standard broke) and to the lens front ring. The tripod bolt (1/4-20) never budged, the Manfrotto 410 gear head never budged, and still works great and the camera bolt (1/4-20) never budged, or even rotated! The camera was repaired relatively easily and is still in use, as is all of the gear. Go out and take pictures!
Dave