LaBounty Truing Sleeve

The bolt fixture takes care of holding the bolt to perform the necessary machining operations.  The action truing sleeve is a sacrificial piece of tooling that has a hole diameter that is a close fit on the outside diameter of the action.  By mounting the action on a mandrel that is a close fit in the bolt raceway, and the sleeve onto the front receiver ring, and then placing the whole unit between centers in the lathe and turning the sleeve, then a surface that is concentric to the bolt raceway is created. (Look at the picture below). The front face of the sleeve is also machined.  While it is mounted on the mandrel, the front face of the receiver is also trued.  Remove the complete unit from the lathe and remove the mandrel from the action.  Do not disturb the sleeve.  Chuck the action/sleeve unit in a four-jaw chuck, the tang end into the spindle, leaving about one-eighth of an inch of the sleeve protruding from the chuck.  Dial in the sleeve both on the diameter and on the front face of the  sleeve. With an appropriate boring bar, the locking lug abutments can now be trued to a right angle with the bolt raceway.

The two arrows are pointing to the two screws that bear against the mandrel. These screws clamp the action to the mandrel.  On the opposite side of the truing sleeve is a hole for a screw that threads into the front guard screw of the action, thus attaching the truing sleeve to the action.

This is the action mounted in the truing sleeve and dialed in, ready to machine the locking lug abutments with a boring bar. The arrow points to the front of the action.