single shear/double shear huh?

[volaredon]

This came up at work today, long time since I'd heard it
but back when I was doing fab work at the steel mill it came up more often.
(No I wasn't the "lead" fab guy when I was there)
What is "shear"? Difference between "single shear" and "double shear"?
I do some small weld/fab projects here at home in the garage at home
now that it has come up once again I figured I'd better ask;

 

[A_Pmech]

It's an expression of how many shear planes intersect a part, usually a fastener.

A single lap joint places the fastener in single-plane shear. A **** joint with internal and external doublers places the fastener in double shear.

 

[Buckgnarly]

Think of two pieces of metal bolted together...single shear. Now think of one piece sandwiched by two others, bolted together....that's double shear. Oh yeah, think about trying to pull them in opposite directions.

 

[Zeke]

What A_Pmech is saying in lay terms is a double shear is a pin or spherical rod end inside a fork. A single has it mounted on a surface.

 

[bczygan]

 

[RogueFab]

A picture is worth a thousand words! Thanks for posting.

As the pic illustrates, it is how many times a fastener will be cut if only the fastener failed in a bolted joint, and nothing bent. It is a theoretical point, and a very valid one. Double shear is theoretically twice as strong.

Common follies: Shock absorbers on lifted trucks. One shock mounting tab is single shear on the bolt. Two tabs, double shear.

 

[bczygan]

A picture is worth a thousand words! Thanks for posting.

As the pic illustrates, it is how many times a fastener will be cut if only the fastener failed in a bolted joint, and nothing bent. It is a theoretical point, and a very valid one. Double shear is theoretically twice as strong.

Common follies: Shock absorbers on lifted trucks. One shock mounting tab is single shear on the bolt. Two tabs, double shear.

And Google has a million pictures.

I always do a Google search for images. It gives me pages of results, to pick the best one from.