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
Preston-Columbia CA
"If you want nice fresh oats, you have to pay a fair price. If you can be satisfied with oats that have already been through the horse; that comes a little cheaper."
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.Originally Posted by Bruce Watson
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!
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.
Wilhelm (Sarasota)
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...
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..!
Speed Graphic 4x5 for LF, DIY wet / dry plate getup for ultra LF, Rolleiflex for MF, a bunch of others for 35mm.
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.
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.
Bruce Watson
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
Your fears are irrational. And "strong loads"? Compared to the strength of the bolt, the loads you are worried about are negligible.
It does not. You'll have to exceed the bolt's yield strength to "stretch" it.
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.
But have you heard about it on AM talk radio? Where there's nothing but the truth, the whole truth, so help me...
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.
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.
Bruce Watson
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.
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