Your present Sherline tool post may be modified to accept these special tool holders, but an easier solution is Sherline's special tool post. It is designed to fit the larger 3/8" square and 3/8" round tool holders commonly used for carbide or diamond inserted tips.
It will also hold Sherline's own P/N 2256 (RH) and P/N2257 (LH) 35 degree inserted tip tool holders.
It is machined form solid aluminum and has a black anodized finish. Purchase of this tool post will allow you to keep your standard tool post available for use with 1/4" high-speed steel tools for jobs where they are sufficient and /or a specially ground and shaped tip is required.
7600 Sherline 3/8" Insert holder tool post Instructions
CA Prop 65 WARNING: Drilling, sawing, sanding or machining wood products can expose you to wood dust, a substance known to the State of California to cause cancer. Avoid inhaling wood dust or use dust mask or other safeguards for personal protection.
I can do all this through him who gives me strength. Philippians 4:13