Brian,
I too like the look of knurling and then jazzing it up with machining some thin grooves that expose a clean surfaces. I use the NIKCOLE Mini-Systems™ to do the grooving (the turnbuckle grooves 0.051" wide). NIKCOLE sell all types of grooving, cut-off and radius carbide inserts that fit in their tool holders. The best part is the AR Warner HSS AISI T-15 inserts also fit the NIKCOLE tool holders and these can take a lot more abuse. The T-15 inserts are super tough for machining extreme materials like titanium alloys, Inconel, and Waspalloy. One drawback with the NIKCOLE inserts is to remember to start cutting the groove slowly feeding in before speeding up the in-feed or risk chipping the tip (the carbide inserts are not cheap!). Thanks for the feedback.
Paul