Best Straight Edge Quality and Price to buy?

[Bruce Page]

I have the Veritas 38" aluminum straight edge. Flat to 0.093" over the length. It is good enough for my shop uses.

Um..typo? My Veritas 38" has a claimed flatness of .003. I checked it against my 48" milling machine table and could not get a .002 feeler gauge under it anywhere along its length.

[Warren Lake]

I hang mine as well, is that the best way to store them? It was past life a shear blade so has mounting holes in it already. I keep in in the office as least humidity in there.

[Aaron Inami]

Below I have pictured:

Kinex 874/0 spring steel 750mm straight edge (29") - tolerance of .00037" over entire length

Kinex 875/0 precision flat square 500mm x 330mm (19-3/4" x 13")

Stabila 32" Model 196-2 level

IMG_0515.jpg

The higher thickness of the Kinex straight edges helps make sure the straight edge is sitting perfectly vertical when laying it on the "edge". This means you can do things like this (to align toe-out of sliding table saw):
IMG_0516.jpg

Also, the steel composition is required when using a magnet mount dial indicator. I have never used the really thin 1/8" or 1/4" Starret/Veritas, but I imagine the thicker material on the Kinex helps reduce flex for doing stuff like this (can be used to align jointer tables):
IMG_0518.jpg

If you are just checking flatness of tables, then those $89 set of aluminum straight edges from Amazon would likely work very well. The higher end Stabila levels are more expensive, but I think they are inherently more useful as a tool. They are made from solid aluminum and the edge surface is machined flat (you can tell by the swirl marks from the milling cutters):

https://www.amazon.com/Stabila-37448...dp/B00009OLI2/

Anything requiring the precision of dial indicators really needs a good steel straight edge (in my opinion).

[Bill Dufour]

I had forgotten that ‘three way’ test . Made sense when I read about it , but it’s gone now. But ,as I reported earlier, when I struck a
line then turned the straight edge around to to align with…line I had made ACCURACY.

All that test proves is the straight edge is straight or it is symmetrically curved over it's length. That is why you need to compare it with two other ones. A single pair can be curved in opposite directions and mate perfectly. A third example can not mate with both if the are curved to mate.
A nut and screw gauge mate perfectly but the bolt is not a straight edge.
Bill D

[Kevin Jenness]

All that test proves is the straight edge is straight or it is symmetrically curved over it's length. That is why you need to compare it with two other ones. A single pair can be curved in opposite directions and mate perfectly. A third example can not mate with both if the are curved to mate.
A nut and screw gauge mate perfectly but the bolt is not a straight edge.
Bill D

I believe Mel's test does prove straightness as it is testing the straightedge against itself rather than a complementarily curved one. It would be easy enough to see a few thou deviation from straight with a clearly knifed line as it would be doubled when the straightedge is flipped over and offered up to the line. For really precise testing you want a qualified service like this one http://www.petsch.digitalspacemail8....alibration.htm

[richard poitras]

Thanks for all the info and thoughts, by the looks of it I think a lot of the aluminum edges may come from the same manufacturer? I was using a 4 ft level but have never checked it for being that straight. So, I think I may look into that before getting a designated straight edge, as mine is a Stabila with the milled face.