Need to be able to use two different bolt in a hole

[LDevitt]

I need to be able to use both a 3/8" bolt and a 5/16" lag in a hole in a small U-bracket while being code compliant. We use a AISI Standard as our guide. According to it the largest whole I can use for the 5/16" lag is a 0.375" with a washer. I was wondering is there is a way around this max hole size by using a thick oversized washer. If so, what standard can I use to justify it.

 

[MiketheEngineer]

Lags are typically used in wood??!! Once you use that - the 5/16'' isn't going to be worth a crap!!!

 

[SnTMan]

LDevitt, seems odd that the presumably weaker connection uses the smaller fastener. Why not make both the same diameter?

Regards,

Mike

 

[LDevitt]

The 5/16" is for a connection to a wooden beam, while the 3/8" is for an existing bolt hole.
The PM doesn't want to increase every thing to 3/8" because it would be wasted material and cost.

 

[dik]

Can you provide a sketch showing the use of the lag and 3/8 bolt? Is the 3/8 bolt a 'through bolt'? I don't understand the application.

Dik

 

[LDevitt]

The U-bracket is similar to the one shown. It is supposed to hold a leg that will resist wind and snow loads on a roof. Most of the time it will be mounted directly to the roof using the 5/16" lag. But occationally it will be used with a stand-off using a 3/8".

http://www.civicsolar.com/sites/def...roduct_full/product_images/panels/tiltleg.JPG