Hi Paco, If you want to get a proper fit to the horn you are using, I suggest that you go to a music shop or an instrument repair supply house and get yourself a tuning peg reamer. Its tapered to the very same taper on your peg. I use it whenever I'm making a horn and I'll usually fit the peg so its about an eigth of an inch from the stop ring on the peg to the end of the horn. When you place the peg into the horn's spout, it will be a friction fit which requires only a light slow twist to get a good seal with the horn. Try this, I think you'll like the end result. Good luck. Wolf