[Jim27]

I picked up a small mill that looks to have some sort of pneumatic collet closer but I know nothing about them or how they work so looking for some help. Not sure I am using the right terms to describe either. It's an old machine from Yuasa so I doubt I can get anything from them. Haven't found anything online for small mills of that brand online. It has what looks like a conventional drawbar bolt with hex at the top for securing the R8 collet. I am guessing that the bolt is adjusted so that the air part can expand and tighten the collet. When releasing I expect I would need to tap the end of the drawbar to release the tool like fully manual drawbar (only one port so it appears to only apply pressure in one direction)? Any issue with just using this without air? This is just for personal hobby use so speed isn't a big issue. Is this basically just a vertical air cylinder with orings so the center can spin? I did a bit of searching to find some basic info on how these work and are constructed but came up with nothing but places selling them with little detail. It's the part covered by the white piece in the pic and has an air hose coming off the back side. What pressure should I be using? I could just hook it up and apply pressure slowly and observe movement - seems like a good first step until I know more.

[Jim27]

Just read the install instructions for the Tormach power drawbar. In that case the cylinder pushes down on the drawbar to release the tool and belleville spring washers provide the force to hold the tool. Thinking that may be how mine works although the parts are arranged differently.