Icosahedron Machining? Ask a Geometrician

20-Sided Machining What's an Icosahedron? Tormach PCNC 770 Owner Chris Moller recently programmed a 20-sided part to cut on his 4th Axis with SprutCAM. Here's some video he shared with us. He's using an ER20 TTS tool holder held in a 5C collet adapter to deal with some tool clearance issues with the 5C collet closer. Nicely done, Chris! New ER-16 Toolholders on the Web We now have ER-16 TTS toolholders for sale. Check them out here. The ER-16 size is just a bit smaller than ER-20. They can be handy for getting into certain areas where ER20 just wont fit, and they're also a tad less expensive too. The ER-16 size holds collets up to 3/8" in size, vs. 1/2" for the ER20 holders.