Countersinking W-1268 Bottom Skin Doublers

Today consisted of several short work sessions working on the six F-1204Z L&R bottom stiffeners and the W-1268A-E bottom skin doublers. The six F-1204Z bottom stiffeners come all attached to one another and required being run through the band saw to separate the pieces. Once separated the pieces were deburred and are now ready for priming.

The ten W-1268A-E bottom skin doublers were separated and deburred a few weeks ago when it was necessary to determine which rivet holes reside above the doublers. At that time, all the rivet holes on the bottom flange of the ribs were dimpled except for those holes that are directly above the W-1268 doublers.  The reason for this is because the doublers are too thick to dimple so all of the holes in them will be machine countersunk for the flush rivets being used for the DOG Aviation RV-12 … as such, the rivet holes in the ribs above the doublers will not receive dimples.

The only thing that was left to do to the W-1268 doublers prior to priming was to machine countersink the doublers to accept flush rivets.  A small board was clamped onto the workbench and used as a backstop to secure the doublers onto during the machine countersinking.

                                       Using the countersink cage outfitted with #30-120 degree bit to machine
                                        countersink one of the W-1268 bottom skin doublers for flush rivets.

The six W-1204Z bottom stiffeners and ten W-1268 bottom skin doublers ready for the primer department.