Are your straight edges straight?

[gene]

Howdy,

We had a post recently about rulers and tape measures not being accurate.


4' x 8' sheets of plywood have very consistent straight edges on them. I found it curious when my straight edge ruler  was telling me that a factory edge on a sheet was not straight.

I then checked my straight edge with other straight edge rulers and low and behold it wasn't straight.

One edge of the straight edge is straight, the other is not. So, it's not that it got bent. It must have been cut that way.

"http://i830.photobucket.com/albums/zz228/genejoe/DSCF2604.jpg";



gene

[byhammerandhand]

The ABC of straight edge:

http://home.comcast.net/~jaswensen/machines/straight_edge/straight_edge.html

[Mike]

I use a 7' straight edge it was a fibberglass bow used for supporting a cover like a truck tonno cover I have a long and a short, had them for years and never thought to check it

[Mojo]

I use straight edges that I buy at Lowes. They are 60 inches I believe. They are powder coated and if you want an awesome cutting surface for your hot knife, these things are it. The blade just glides across them and they cut clean ( and fast ).

You can find them at Lowes in the tool section. They are yellow.

I use a large square to square off the corners and use a straightedge under the square.

Chris

[forsailbyowner]

At one time in my life I was involved in commercial metal framing. Before a new framer came on the job I would always check his level for accuracy maybe 1 out of five would be within 1/8" in four feet. When I bought levels I would cull the rejects out of the box and often come up with none that passed the test, and these were expensive magnetic levels. Reminds me also of the time I bought a $90 torque wrench that was 30lbs off. Definately gotta check every measuring tool against a standard, sure can't count on manufacterers.