I too have been having problems embossing brass stencils. Have tried many "Sandwiches" but can only get them through with alot of force, which having carpol tunnel was the reason for buying it. Have contacted the place i bought it from and she is going to send me anothe one. I can do everythjing else with it no problem, but really wanted it for embossing, as that is what really hurts my hands.
I did think when i was forcing it through that one of the plates may break!!