< Cylinder Block Cutting 3 >
In order to finish the inner cylinder cover face, the inner cylinder jig (reported last month) is set on the milling table vertically with a large angle plate. The pins for jig are not necessary here.
The cylinder casting is clamped on the jig with a large C-clamp. First, the back cover face is faced up. Lower ends of the outer cylinders touch on the stage but adjusted with shims, so that the back cover face becomes truly parallel to the table.
The back cover face is roughly cut by endmill and finished by fly cutter.
Unwanted wall between inner cylinder and inner steam chest is removed by a sanding bit.
The front cover face is aligned parallel to the back face without the jig. The front face and inner wall are cut just like the back face.
There are snifting valve flanges at both sides of the cylinder casting. The flange faces are fly-cut in the lathe.
The snifting valve boring height is a little lower than the valve chest center height. Therefore, the lathe center cannot reach the boring height in the reversed setup. Also I cannot utilize milling machine because the machine height capacity is less than the width of the casting. I got into a fix!
In the last resort, I drew out the lathe table and put the casting direct onto the saddle with a suitable packing. In order to clamp the casting, the lathe table is drawn halfway and holds the job with angle plate. The screw handle is no longer effective in this position, so I adjust the table position with a small hammer and lock it. Thus the center hole is drilled and reamed. Note the tail stock pushes the casting against the drill.
The last operation is for the steam inlet flanges. The flanges tilt in 15 degree. As the photo shows, the casting is aligned at 15 degree by angle plate and round rod. Note another angle plate pushes the casting so as to prevent slipping.
First the flange face is cut by endmill and fly cutter.
The center hole is drilled. Also the bolting holes are opened.
Finally unwanted edges and burrs are removed with files, then the troublesome process for the cylinder block is almost completed, still I need to open a lot of screw holes...