The holes in the thimble's indentations let moisture escape, permitting the evaporation of sweat. While you may not be visibly sweating, a solid thimble can hold in enough moisture to make your thumb look as pruney as it would after an hour in a bath tub.

What are the holes in a thimble for?

One of the most common discoveries that historical homeowners often come across is a chimney thimble port; a circular hole in the wall used to house a thimble. The thimble enters the flue inside the chimney and is designed to accommodate a stovepipe.

How do you make a hole in a thimble?

To make the hole, use a very pointy punch to make an initial dent in the thimble, close to the top rim. Place the thimble with stick on a leather glove, and hold the thimble and punch in place with one hand and the hammer in the other. Then, carefully tap the punch several times until you get a good indentation.