thoughts on how to measure the depth of engraving on a can or sbr?

I've always heard that if you can catch you fingernail on the engraving, that's a good indication you're good to go. Don't lose sleep over it.

I agree with this.


Approx ~ thickness of a piece of notebook paper.

It's not something worth testing.

Do you best to comply and you'll be fine.

^this

It's 3 thousandths of an inch. I can't fathom they would ever try to prosecute someone for being off by a thousandth or two. Not to mention how they'd ever determine that without using some pretty specialized tools.

The only things an ATF agent could readily check are the size of the font and that the necessary information is there.

When a customer's weld specifications called out "no more than 0.010" of undercut" and began rejecting our parts based on that specification, we asked them "How are you measuring it?" because like engraved text, something could be .010 wide and .009 deep and there isn't much in the way of metrology devices that would allow someone to measure it.  Their reply was "If we can see it it's that deep."

So I made a device that would hold a 0.001" button indicator in a block, and in the block pivoted an arm which had a very fine probing point on one end, and a rest for the indicator button on the other end.  They accepted that device as being the last word on how deep undercut was.

The only way I can think of to actually measure depth of engraving is in a similar fashion.  A test indicator with a probe fine enough to actually get past the wall of the engraving.

And not worth your time.  The fingernail test is best, IMO.

If you really want to check it use a point micrometer or a dial indicator with a point that fits in the engraving.

Metal stamping almost always goes well beyond the minimum required depth. Its etching or dragging a diamond point engraving tool around the surface that is sometimes light or shallow.
The other option is to have it laser engraved / burned for $60'ish that looks professional and is guaranteed compliant if it really is engraved and not etched.


If you are REALLY bored cast the engraving in Cerrosafe and section it and view it on an optical comparator.

We do engraving at work and use these,

Link

They work great but most likely not cost effective for you

thanks

I used metal letter stamps, they turned out really well IMO. The trick is to lay a piece of straight masking tape down the tube so that you can line the letters up by sight and feel (when they touch the edge of the tape). Three light taps at three different angles will roll a letter around the tube at an equal depth. It helps to lay out all the letters you need before starting to make sure they're all there and mark them with marker so you don't stamp one upside down.

Just remember, if you do decide to measure, it's from the flat surface of the metal and not the raised ridge that engraving may cause.

(5) Measurement of height and depth of markings. The depth of all markings required by this section will be measured from the flat surface of the metal and not the peaks or ridges. The height of serial numbers required by paragraph (a)(1)(i) of this section will be measured as the distance between the latitudinal ends of the character impression bottoms (bases).