How is this ok?

[bluedog225]

Is there some logic at work I don’t understand?

It’s a 1/2 inch lag bolt that measures 0.335”.

That throws off, well, everything.

Surely I’m missing something.

Edit-I guess it’s the thread diameter that is normally stated. Still short. But the shank diameter seems so far off.

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[sp_clark]

“Nominal” dimensions. Same as a 2x4 measuring 1-1/2” x 3-1/2”.

Those SPAX hardware lags aren’t same steel as traditional lags either so they can get away with less metal & still meet specs a 1/2” conventional grade 2 lag does.

[bluedog225]

But why would you buy a grade 5 half inch fastener to meet grade 2 specs?

[Hugh Conway]

But why would you buy a grade 5 half inch fastener to meet grade 2 specs?

dis why

SPAX PowerLags are ICC-ES and DrJ code-compliant for deck ledger attachment multi-ply applications and do not require pre-drilling for full strength ratings, offering dramatically increased installation speed across your projects.

[bluedog225]

I think you are right. It’s implied that “full strength” is grade 2. I can’t find it expressly stated that you are buying a grade 5 equivalent of a grade 2 bolt because it is easier to install. I love the GRK and Spax fasteners. But this seems shady as heck.

If I were buying a 1/2 hex head lag bolt, I would expect to get something like this:

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[sp_clark]

I use these rather than conventional lags strictly for their appearance.

Similar engineering to those SPAX fasteners but with a truss head shape and a six-lobed Torx drive socket I’ve become a fan of.

A few times I’ve managed to twist the heads off conventional hex-head lags, have yet to do that to a Torx-drive head type.

[wizbang 13]

Spax wearing Spanx ?

[bluedog225]

Thanks. Comparing the Hillman to the Spax.

At the stated 5/16, the Hillman major diameter is 0.305-0.315.

5/16 is 0.3125 (actual)

The 5/16 Spax major diameter is only 0.217.

Though the Hillman doesn’t state a grade. It does list the tensile strength. I haven’t done the math to figure out the grade.

For the normally intended use, something like deck building, I suspect they are all fine.

Interesting stuff. I enjoy digging around in this type thing.

I keep ending up back at the old fashioned hot dipped hex head lag.

[sp_clark]

Thanks. Comparing the Hillman to the Spax.

Interesting stuff. I enjoy digging around in this type thing.

As do I. Metric stuff's even more interesting....

I keep ending up back at the old fashioned hot dipped hex head lag.

For the OP's intended use, I'm with you on that. Appearance doesn't count as much as longevity and strength. Good enough is good enough for his purpose.

[Stiletto]

I can understand your concern. If you want a half inch bolt, then that's what you want.
My impression is that the manufacturer of the Spax bolt is claiming equal or superior performance to the one you wanted, along with avoiding the need to pre drill a hole. It is hard to determine whether that these claims have been proven by an engineer, or are just designed to make a sale. In America's litigious society, the latter would seem to be a risky path to take.

[Peerie Maa]

The performance may be the same in tension, but will not take the same shear load as there is less bearing area in the wood.

[bluedog225]

In my opinion, this is a more accurate, defensible approach.

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