[Travis McGee]

Note of interest: Just grinding off the surface layer of metal does not erase the numbers. The impact of the numbering die leaves changes in the subsurface structure of the metal that can be used to discover the “erased” serial number.

So, anybody doing this, in some hypothetical un-free country, should first smack the crap out of the serial number with metal-working “center punches” and chisels. THEN grind off the mess.

[Bloody Sam Roberts]

Good advice. I'm good at woodworking (quite good actually) and have only a fleeting relationship with metal work. Though, I'd like to get into forging someday.

Thanks.

[PapaBear3625]

Better would be to mill out the piece of the frame where the serial number was, if the resulting hole does not compromise the structure of the frame.

[Max in Utah]

True. Stamping distorts the grain structure of the underlying metal. If the spot is polished and then treated with acid, the number can often be read using a microscope.

I’ve occasionally seen a “ghost” serial number after machining away .010” to .015” of material when reworking an incorrectly marked piece. The characters showed as slightly raised figures. This effect resulted from localized work-hardening from the die’s impact.