Razor v5

I started with cwills75's "Retractable Razor Blade Utility Knife" which is a remix of the Talon V2 Utility Knife by HallPrecision.

I made a series of modifications and I am now satisfied with my 5th redesign. I'm calling it "razor v5". This is now part of my EDC kit. The Razor v5 fits perfectly into my jeans' watch pocket.

WARNING

Razor blades are sharp, so be careful! If you do cut yourself, do not blame me!

Features

Some of the features I added, which are important to me:

• must fit the serrated razors I use
• tip of the blade must not protrude when in the closed position, so I don't cut my jeans or fingers
• stronger locking in the closed position
• stronger locking in the open position
• larger unlocking holes
• added a more grippy top surface to slide the blade in and out
• two locking blade positions, since I rarely need to cut deeper than a few millimeters.
• added a stop position so that the blade should never protrude past the full extended position
• decreased slop of the blade as it mounts into the top male piece
• re-added a keychain hole, even tho I don't plan on storing this on my keychain
• curved unlocking holes so a thumb-nail can more comfortably unlock and retract with one hand

Print Settings

I have not decided which layer height I prefer, but I've gotten good results with 0.12mm, 0.16mm, and 0.20mm layer heights, using a 0.4mm nozzle. I use 100% infill, no supports.
I tested with PLA and PETG, and while both work well, I prefer the more flexible feeling of PETG.

Assembly

Razor blades are sharp, so be careful! If you do cut yourself, do not blame me!

I found it best to test fit without inserting a razor, and slide the male into the female and extract/detract about 10 times until the action is smooth. Then disassemble, and install the razor.

Usage

With good technique and practice, the blade can be opened and closed with one hand. However, I might make further improvements in v6 so that it's easier for my wife and children to operate this safely.

Encouragement

I would appreciate any feedback as I develop v6, and I would love to hear how this design works for other people.

If you like this design and want to encourage me to make further improvements, consider buying new serrated razor blades using my Amazon.com affiliate link: All-Purpose Serrated Utility Knife Blades