this isn't a box lug your showing?, but Steve Maxwell sells box lug replacements here in the states, I don't know if the hole diameter is the same, here's the link! http://www.maxwelldrums.com/leedy-custom-shop-leedy-lugs-c-192_163_166.html

the x-lug is the box lug, from cooper website> http://www.coopersvintagedrums.com/leedylugs.htm

In 1929, the Leedy Drum Company was sold to the C.G. Conn Company and a true innovation in lug design was introduced that year. Known as the “X” lug or “Box” lug, this new tension casing was attached to the drum shell from inside the drum with two screws. Here is an example of an early 1930’s Leedy lug made of cast aluminum. There were at least two or more versions of this lug that I know of and they varied in size and design. The earlier versions had small screws that held the inserts in place. Eventually, an internal copper spring was added in order to allow even more flexibility and eliminated the need for these screws.

Thanks for your reply!

I only got the term "box" lug from Maxwells website where he uses the term:

http://www.maxwelldrums.com/leedy-5x14-snare-drum-gold-sparkle-1920s30s-p-2972.html

I was interested in buying that drum but he says some lugs show signs of cracking. I just want to be sure if there's a way to replace them if they do crack.

It doesn't look like it though.