If you need to use a tool with a different shank diameter on your Carvey, you will have to replace the collet. The ER11-A collets used by Carvey will only accept tools with shank diameters equivalent to that of the collet bore and vice-versa. To replace the collet, start by using the 13mm and 17mm wrenches supplied with your Carvey to loosen the collet nut and remove any tool present. Keep loosening the collet nut by hand until the nut-collet assembly comes off of the spindle. The collet is clipped into the nut with an eccentric retaining ring on the nut. To remove, use your thumb to apply sideways pressure at different points around the top of the collet until it tilts as far as it can in the nut. You should then be able to wiggle the collet free. To install the new collet, press it into the nut until it snaps into place. Confirm that the collet is properly seated and thread the assembly back onto the spindle. You can now install a cutting tool.