Couldn't find a needle file handle I was happy with, so I made another. The needle files from my local hardware store are 3mm (1/8") in diameter and so the handle is sized accordingly. If your files are a different size, let me know the diameter and I can export another stl file.

Features:

• Handle is designed to print horizontally, so the fingers of the collet flex instead of breaking. 
• Beefy ½-13 UNC threads allow for a tight hold on the file
• Clamping at the front of the front of the tang to minimize flexing and vibration during use

The nut prints just fine vertically. I use a little bit of hand soap to lubricate the threads.

Recommend settings for printing the handle horizontally:

• Auto-generated supports: Yes
• Support only on build plate: Yes

Update (3/11/2024):

• Address a weak point in the nut
• Smaller, rounder handle
• Add tabs to make printing easier