CNC jimping

[wayup]

How is fairly small (say around 1/32" radius) semicircular jimping done on blades and titanium handles with a CNC? Are a series of holes drilled first and then the profile machined? Or do you try to come in sideways after the profile is machined?

How about for jimping I see on some knives that looks more trapezoidal shaped (with pretty sharp corners). Is that done with a CNC grinder?

 

[Daniel Carraher]

Checkering file does the trapezoidal ones. I use a 3/64 ball nose end mill vertically. Have used drilled holes in the past but since I’m manually milling them I like to use a ball nose end mill as the last step after finish profiling.

 

[Drew Riley]

You can get pretty fine details with some surprisingly small endmills, but a lot of the productions companies like Spyderco, for instance, are likely using a laser to cut their fine jimping.

 

[Nathan the Machinist]

I expect that a lot of the jimping that you see is done in a laser or water jet cut blank. But any jimping that you see that has a nice finish in the root of it was probably milled or ground. I cut mine with an end mill, but you could turn the blade 90° and cut it with a threadmill. Some places crush grind. Lots of ways to skin that cat.