Consensus of Opinion - Lag Bolts 90 deg. or Angled?

[Meat Hunter]

What is the consensus of opinion on whether lag bolts should be drilled in straight down (90 deg.) or at an angle?

[FIGJAM]

I don't angle mine and haven't had a problem.

[FossaFerox]

90 degrees. Check my post in the lag bolt thread to see why. I don't feel like retyping it on my phone.

[Token]

Agreed, 90 degree.

Well documented in the HAM world for folks putting up big-ass antennae towers.

Also lots of data from the homesteaders and their wind turbines.

Confirmed, studied, resolved, buried in soft peat for 6 months, dug up, lost, found, and published in myriads of forum posts.

[Pootzen]

Both!



http://suspendedanimationcrew.com/burni ... amp_Up.pdf

[Fan C]

Makes sense to go straight down. With a bolt buried to the hilt there's virtualy no lever so go deep as possible.

I think that's TL;DR of FossaFerox's post in the other thread.

edit. omg I can't believe I forgot about pickets. Well I was just the medic with engineers long ago.

[FossaFerox]

Not both. No. Not with lag bolts.

Here's the short version.

Normal tent stakes fail by pulling out without bending or snapping. To make them stronger you make sure the guyline is pulling perpendicular to the stake by setting the stake at an angle. This works reasonably well for shallow sets in a consistent soil with relatively low load.

LAG BOLTS don't simply pull out. The load on them torques the bolt causing the deep-set tip with the threading to break free of the dense material they're gripping (they're threaded for a reason). Then they pull out. They usually bend in the process.

Stopping/reducing breakout/bending prevents the deepest part from coming free, so we want LESS perpendicular force. We WANT the in-line, pull-out force that normal camping stakes are not designed to handle. By setting the bolt vertically we decrease the torquing/bending force (Causes failure) and increase the in-line pullout force (lag bolts are designed to resist exactly this).

As an ADDED BONUS the playa is MUCH DENSER once you get about six inches down. When you set your bolts at an angle you grip more dust and less of what will actually hold your shelter in place. By going vertically not only is the angle of pull better for the type of anchor but you're getting a much stronger grip at the same time by having more of the bolt set into the denser sub-playa.

TL;DR:

LAG BOLTS SHOULD ALWAYS GO STRAIGHT DOWN.

[Hondovious]

Not both. No. Not with lag bolts.

Here's the short version.

Normal tent stakes fail by pulling out without bending or snapping. To make them stronger you make sure the guyline is pulling perpendicular to the stake by setting the stake at an angle. This works reasonably well for shallow sets in a consistent soil with relatively low load.

LAG BOLTS don't simply pull out. The load on them torques the bolt causing the deep-set tip with the threading to break free of the dense material they're gripping (they're threaded for a reason). Then they pull out. They usually bend in the process.

Stopping/reducing breakout/bending prevents the deepest part from coming free, so we want LESS perpendicular force. We WANT the in-line, pull-out force that normal camping stakes are not designed to handle. By setting the bolt vertically we decrease the torquing/bending force (Causes failure) and increase the in-line pullout force (lag bolts are designed to resist exactly this).

As an ADDED BONUS the playa is MUCH DENSER once you get about six inches down. When you set your bolts at an angle you grip more dust and less of what will actually hold your shelter in place. By going vertically not only is the angle of pull better for the type of anchor but you're getting a much stronger grip at the same time by having more of the bolt set into the denser sub-playa.

TL;DR:

LAG BOLTS SHOULD ALWAYS GO STRAIGHT DOWN.

If it helps to think of it this way.. realize that angling the anchor only helps if what you are relying on is the strength of the shaft. With lag bolts this is not the dominant resistance, the threads are. The shaft is there to support the threads. If the shaft is angled and then is pulled closer to 90 degrees, the threads lose traction with that movement. Think of how we all pull our rebar out of the playa with even its little bit of side gripping. No one can pull that shit straight out, you have to wiggle it side to side and then it lifts right out. If your lag screws are straight down they are less likely to be moved laterally, thus making them stronger.