The sleeves are made from StressProof 1144 steel. This is a nice material to work with, easy to cut with the main benefit of reduced warpage and distortion that needs to be minimized in the final part. A 2 inch diameter 6 foot long bar is cut into 3.7 inch long slugs which yields 19 pieces. One short of the 20 target but that still leaves some margin for a few mistakes along the way.
The first operation on the slug was to faced both ends on the lathe to its final length. These were progressively drilled out on the mill using the trusty ‘Silver and Deming’ drill set to 1.25. A drill will always remove material faster than any other tool in the shop.
The drilled blanks are then bored out on the lathe to 1.372. That leaves .003 for honing on the Sunnen to the final bore size of 1.375 later on.