Straightness of bars

[Creech]

Does anyone have any information or ideas on straightness inspection of thin bars.

I am trying to measure 1/4 aluminum extruded material to what the standard, I believe is, .002 / Ft.

We are buying 12Ft bars. The finished product is 18" long.

Any advice? Thank you in advance

 

[CoryPad]

Are you looking for a technique? Equipment?

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Creech]

Cory -

Yes and maybe. I would like a short term solution and, if not feasible, a long term possibly purchasing something.

- Creech

 

[MikeHalloran]

A feeler gage and a flat surface will do. Any engine repair manual will show you how.

A granite surface plate of sufficient size is not terribly expensive.




Mike Halloran
Pembroke Pines, FL, USA

 

[JR97]

Be sure the surface you are setting the piece on is flat. If you are gap measuring under the piece all your measurements will actually tell you the difference in flatness (straightness) between the part and the surface under the part.

How about mounting a laser pointer (cheap one would be fine) about an inch or so from the side of the piece, then hold a scale (ruler) against the side of the piece every XX inches along the length. Record where the laser hits the ruler at each point. Graph it along with a line connecting first and last point (to compensate for alignment of laser pointer). The variance between the two lines is the straightness of the piece.

 

[wallyd999]

Look in the AMS spec books under your material type and see if it calls out AMS 2300 or 2351 (it think) on gives recommonded stock removal and on applies to stargintness, bending ...

I use it mainly for steel (which the listed ones are) but the alum version should be there too.