How can you drill out the 3/8 axle slot on a bmx frame to a 14mm?

Question

i keep bending axles on 3/8 axles and i don't have money for a cassette or a new sprocket

Answer 1

Drill and tap set.  About $8 at Home Depot.

Answer 2

Bottom line is that this is not an operation you can do.

Trying to get fancy with files or a rotary rasp will likely destroy the frame especially if it is aluminum. 14mm dropouts are designed differently than 3/8" versions to make up for the loss of material.

A cassette or sprocket has nothing to do with bending axles, so am trying to figure out what you mean there.

If you try to do this modification be prepered to lose your frame- and maybe your health.