MK111,
You can use a Demel with a cutting disc too, just make sure you cut it square so that your insert will glue in flush to the end of the shaft.
BTW...when you say they're too long, do you mean for your draw length or the fact that they hang over the end of the bow...while they're in your quiver? If it's a draw length issue, you're fine. If they're too long for a short bow, then you may need to look into a new quiver.
Bowhunter57