Tikka Bolt Knob

The hole in the Tikka bolt handle is perfect for a M10 threads. Thread it, print knob and cap, screw in a short M10 fastener to attach the knob and screw in the end cap.

You may have to turn the screw head down to get it small enough for the knob. I it did using a handheld drill to hold the fastener and a stationary drill with an abrasive wheel.