Lets talk shear vs tension...

Well, it looks like it's mostly already been covered. Use through lag bolts ideally so you're not loading the threads and you should be fine.

Another option you could do if you wanted to make it a bit less obtrusive would be to use either rope or chain through the pipe (with protection from chafing) so you could just pull it up out of the way easily when you're not using it.

I'm a Doctor, not an Engineer... But... Shear v. Tension: From my reading and discussion with actual Engineers (Civil, Nuclear, NOT Electrical engineers), a joint in shear is what you always want to design for. A joint in tension is weaker than a joint in shear. Doesn't matter (much) what type of fastener, pop rivets, welding, bolts, it is stronger in shear than in tension. Now, the structural beams themselves are stronger in tension than in compression, but that's a different topic.

I also agree with the "put some big ass bolts through the beam and call it good" suggestions. Note that the bolts will be in shear.

In reply to Dr. Hess:

Depends. Single shear or double shear? Ohh bolted joint theory.

Smith's books say a joint with fasteners in single shear is stronger than one in tension, given the same number of fasteners. I believe he used Pop Rivets as an example, but it's been about 15 years since I read his books. He also said to always try to design stuff in double shear.

EvanB wrote:

Knurled wrote: I, too, would like to know more. Is it a brittleness thing?

That is the only reasoning I could think of but a gr8 still has a higher shear load than gr5.

You see this thinking in the offroad world as well. I've never been able to figure it out. The "ma daddy tol' me" explanation is that a Grade 5 will bend instead of break, but if you look at the actual numbers that Grade 5 will have bent, then snapped before the Grade 8 has a problem.

Knurled wrote: I, too, would like to know more. Is it a brittleness thing?

Yes, brittleness. A grade 5 will bend and deform. Grade 8 tends to snap. In most situations, it won't matter a hill of beans because we often use a 5x to 10x load rating. If the weakest link is rated for 1000 lbs in a lift line, I won't use it to lift more than 100-200 lbs. So the chances that either a grade 8 or grade 5 would fail is slim.

The main reason I prefer grade 5 in shear for rigging (provided it still maintains an adequate capacity) is shock load. When you have a 1500-lb counterweight arbor flying through space, shock loads can get intense.

This mostly applies to practical rigging. The rig itself is all standard code Grade 8 and forged overkill. A good example of where I used Grade 5 were some sliding barn doors in our last show. The doors were a steel frame with wood doors attached to them. The carrier wheels in the track were attached to the steel frames with Grade 5, not 8. The reason for this is when actors grab those doors and inadvertently ram them against the track stops, the grade 5s can take deflection.

In this particular situation, each door was suspended by six 5/16" bolts and they only weighed about 50 lbs each, so in truth they could likely have been attached with duct tape and not fallen. I just use that as an example of where I prefer grade 5.

A properly tensioned bolt will transfer the shear load to the materials being joined.

Properly tensioned isn't necessarily an easy thing to achieve.

Note: I'm no enginerd, just work in the industry and have taken classes on fastener engineering, the real world can be much different.

Edit: Structural fasteners for building are roughly gr5 in strength. But they are meant to be tensioned well into the yield point so the friction of the materials being joined holds the shear load.

This is delving into the same line of reasoning as those little plastic hub centering rings. The bolts load in tension so that the joint interface is held firmly in shear. If the plastic thingy was needed, the bolts would need to be so loose that they were loaded in shear, at which point the wheel is already falling off.

I'm kinda weird, I think of bolts as really stiff springs that clamp things together, not locating devices holding things in shear.

Bolting into wood is kind of a weird one because you usually can't tighten against wood enough to tension the bolt, so bolts through wood are almost always in shear. Nut and bolt, use more fasteners than you think you need, and maybe Nylocs are a good idea if it's on your trailer because after a couple years most of the nuts will be missing since you could never tighten them enough to properly tension the bolts

EvanB wrote: A properly tensioned bolt will transfer the shear load to the materials being joined. Properly tensioned isn't necessarily an easy thing to achieve. Note: I'm no enginerd, just work in the industry and have taken classes on fastener engineering, the real world can be much different. Edit: Structural fasteners for building are roughly gr5 in strength. But they are meant to be tensioned well into the yield point so the friction of the materials being joined holds the shear load.

Knurled already beat me to it. Many of the things I build also include wood (in fact, nearly all) so you can't properly tension even a grade 2 in wood. The whole weakest link thing comes into play.

One more bit of advice. Keep your head between the floor joists. They hurt if you it them.