Long Length Inspection 1

[Wrenchbender]

We are looking for a method to inspect exterior length features of a steel part on the order of around 13-ft, straight line of sight. We need an accuracy of +/- .020 inches. The primary datum is a flat surface perpendicular to the desired length measurements. Other than CMM, does anyone have any practical suggetions? Field portable use would be a plus. Thanks.

"Very interesting indeed, but tell me, Mr. Faraday, of what use is this electricity?" "Sir, you will soon be able to tax it."

 

[redpicker]

They make laser measureing devices that will do what you want.

rp

 

[MikeHalloran]

A straight steel bar with a stepped face on one end would be perfectly adequate.

You don't even have to look at it; just feel the relation of the part feature to the two faces of the bar; part surface between the two gage surfaces = good part.

See "flush pin gage".




Mike Halloran
Pembroke Pines, FL, USA

 

[unclesyd]

Adding to MikeHallorn's post here is a more elaborate device to do the job. You can buy trammel heads for a bar that would facilitate using it on other projects.

http://www.concentric.net/~Petsch/Stedge.htm#Level

 

[Compositepro]

Traditionally, this was often done with transits and a precise tape measure.

 

[Wrenchbender]

Thanks to all for your suggestions. A trammel bar might work but it would be heavy, awkward and still have to be calibrated. No? So I think laser measuring may be the way to go. It would be more cost effective, except we may have to compromise on the accuracy. Most handhelds seem to advertise +/- .030 inches at best.

"Very interesting indeed, but tell me, Mr. Faraday, of what use is this electricity?" "Sir, you will soon be able to tax it."