What are these cutters for?

[Unmarked Bill]

I have never gotten around to finding out what these are for, and I've never seen anyone using them. TIA!!

The ones on the left look to be home made from a triangular file.

<a href="http://s19.photobucket.com/user/picturedlife/media/20170218_193054_zpsx2smkzvj.jpg.html" target="_blank"><img src="http://i19.photobucket.com/albums/b168/picturedlife/th_20170218_193054_zpsx2smkzvj.jpg" border="0" alt=" photo 20170218_193054_zpsx2smkzvj.jpg" style=""></a>

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[jakemac]

Not sure, looks like glass or tile.

 

[Unmarked Bill]

you know what, you're right. they're for drilling glass, I knew and I totally forgot