The buck-fifty bolt knob

Custom Phenolic Bolt Knob

I'd previously experimented with cast epoxy to enhance the bolt knobs of my Axis rifles. While they were effective, they were never attractive or really that easy to make. I later opted for 5/16-24 threaded bolt handles. This common thread allowed me to use any number of aftermarket bolt knobs, but something told me that I could go cheaper...more homemade.

The seemingly endless array of awesome industrial stuff for sale at McMaster Carr has figured into a number of my projects, and once again the supply house fed my tinker-lust. I picked out a few threaded oval knobs (6050K15) and added them to my next order. The knobs themselves were big for a bolt handle: 1 1/8 inch in diameter, 1 1/2 inch long. They were made out of phenolic resin, a tough plastic material I was familiar with from my experience in knifemaking and collecting Bakelite firearms stuff. While I had every confidence in phenolic's strength for being a bolt knob, I was less convinced of its toughness for being threaded. Thankfully the knobs I chose had a brass insert that would take care of the business of holding the knob to the handle.

One other thing I learned about phenolic resin that's worth remembering: wear a respirator. The material itself is strong, safe, and stable, but once it starts being heated through work, especially by power tools, it can start to give off formaldehyde vapors. This project is about being cheap. Cancer is not cheap.