On a Jr. Gent you can start screwing on the cap from a number of positions -- I think 3 or 4. I assemble the pen barrel portion first. I then screw the threaded insert onto the nib and carefully hold the cap against the black plastic portion of the insert as I first eyeball and line up the grain patterns and then carefully unscrew the barrel/nib, hold this orientation of the insert to the cap and then press the insert into the cap. Then when I'm done assembling the cap I can find the proper 1 in 3 or 4 starting positions, screw the cap onto the pen, and the grain pattern lines up. Of course the next time someone takes it apart and then screws the cap back on they only have a 1 in 3 chance of getting it right!