Subscale Engine Mandrel

 This aluminum mandrel is sized to be the same as the chamber from the previous vehicle, BZB. This is to test and refine creating the silica-phenolic ablative layer of the chamber. It is a smaller scale than the final chamber so we can use less material while we determine the optimal technique for making the chamber. The mandrel was made in two separate parts on a CNC lathe. 

The CAM was made in Fusion 360 with models of both the stock and the table/lathe spindle included to prevent crashes. The workholding was a 3-Jaw chuck on both the mill and the lathe to grip the stock by the outer diameter. It also required deep-drilling to have the threaded rods connect the two pieces together. The hole depth very nearly maxed out the length of the drill, but had just enough clearance to work. The drills were HSS, so a spot drill was required to prevent drill walking.