Trying to determine intended use for a knife tool

[ihrescue]

Greetings all -

I hope I can get some help with this knife I am working on. Up front I'd like to answer a couple of questions -

1) What is the intended use of the tool included with this knife?
2) Do you know who may have manufactured this knife?

Here is a description and some photos

I have a fancy folding pocket knife about 3" long I am trying to identify. It is from 1946 (based on the scale engraving). It has brass or possible brass plated metal scales. That it is not plated because the finish is completely intact, no wear and no peeling. I am thinking this is solid brass. I haven’t done a magnet test yet on the scales. On the scales are fancy carvings and in the center of the scales are blank spaces for engraving. The tang marking on the pen knife blade on one side says Made in the USA and on the other side it says Sheffield Steel. It has a single pen knife blade. On the back side is a very thin spike, almost like a thick needle, that has a narrow pointed end and the facets of the spike are grooved like a rasp. One possibility is that it is simply another way to make a fingernail cleaner and file without taking up much space, materials or weight.

While the blade, tool and interior with springs have some rust and there’s small nick on the blade, it is in pretty decent shape. I have soaked it in mineral oil and used a new razor blade to scrape most of rust off but haven’t gone to using any cleaning efforts yet.

Thanks for any comments you can contribute on my two questions as well as any observations about the knife in general. Cheers

Mike
Central Maryland, USA

[Mumbleypeg]

That is a fingernail cleaning/file/cuticle tool. Very common on similar knives of that vintage. (Often referred to as a “lobster” pattern, the springs are internal). The knife inside the covers is what is called a “skeleton” knife, manufactured without the handle covers and sold to jewelers who affixed covers, often of gold or silver plate, or as in this case, brass. Some were sold as gifts and engraved with initials or names of the intended recipient. Some of them had a bail for attachment to a chain for use as a watch fob. Many “skeleton” knives were made by Imperial and Colonial, there were others.

Ken

[orvet]

Ken nailed it!

[ihrescue]

Ken - thanks for that excellent answer. I did find elsewhere that Colonial obtained Sheffield Steel for some knife production. I appreciate learning about the practice of the skeleton knife.

Mike