Lag Bolts for Wood

[kevanthurman]

I am designing the mount brackets to mount solar panels on a roof. I have calculated the pullout force to be 1260 lbs per bolt and can only use 2 bolts (i.e. total pullout from wind load is 2520 lbs). The bolts are to be 1/4" and mounted in Doug-Fir wood. This means I would need 5.5 inches of embedment in the wood. Does anyone know where you can get Lag bolts with 5 1/2" of thread?

Thanks for your help, Kevan

 

[Ron]

Try Googling....

here's one link...

http://www.fastenersuperstore.com/s...m?partId=170046&productCode=LG&category=Bolts

 

[BAretired]

Good link. 1/4" x 6" is shown in the picture.

BA

 

[jberg]

I am not sure where you are located, but you could also try Fastenal, Grainger or a similar store. Here is a link to Fastenal's items. Many of the different types of lags are in stock at different stores if it is a rush.

Joel Berg

 

[racookpe1978]

I'd use 5/16 bolts, maybe 3/8. Did you check the capacity (plus margin) for 1/4 bolts?

 

[csd72]

Are you talking lag bolts or screws?

 

[apsix]

It's probably American English.
The fastener pictured in the above link is what I would call a coach screw.

 

[csd72]

I never realised that a lag bolt and a lag screw were the same thing, probably because I have never used the term lag bolt.

 

[kevanthurman]

Thank you every one for your responses. I was able to use a 3/8" X 7" lag screw from Fastenal.