< Cylinder Block Cutting 2 >
Now I start boring the outer cylinders. In order to fix the cylinder block firmly and precisely on the lathe table, I prepared a jig as the photo. The angle plate is cut to proper height and fixed on the table truly parallel to the lathe bed. A steel plate of the same height faces to the angle plate. The screws and nuts are to adjust distance between the angle plate and the steel plate.
The cylinder block is set onto the jig and the nuts are tightened. Then the bore is aligned correct height and parallel to the headstock. I added overhead clamper so as to secure the job firmly.
After fly-cutting the bolting faces, the bore is finished with the same boring tool as the steam chest.
This is a cylinder honing tool for automobile air cylinder. I employed this to finish the cylinder bores.
With plenty of cutting oil, the horning tool goes back and forth with spinning until the bore surface becomes smooth.
This is a damage of crash between the casing and the lathe headstock. The accident occurred because I forgot to stop the lathe at the bore end. The damage did not reach to the bolting radius, so I continued the operation.
The rest of boring operation is for the inner cylinder. It is the most difficult because the cylinder block has to be tilted in 7.5 degree from the lathe headstock. Also I cannot fly-cut the bolting faces in the lathe because the steam chest projections obstruct access from both sides.
So as to setup the cylinder block, it needs two positioning pins. Holes for the pins are opened here. I took this opportunity to open all of screw holes for the top flange. In the photo, the hole at the drill tip is for the positioning pin. There is another hole at the symmetric position.
The photo shows jig for the setup. Two rectangle bars are spaced in proper distance by thin round rods glued into the bars. Top faces of the both rectangle bars are cut in 7.5 degree. There are two positioning pins on the higher bar. Incidentally, two black screws on the lower bar will be removed before the setup. The higher bar is fixed firmly onto the table with four sunk screws.
The cylinder block is reversed and mounted onto the jig with the positioning pins. Then the inner cylinder is truly aligned to the lathe center. After that whole job is clamped from the top and the cylinder bore is finished by the boring tool.
I will report how I cut the cylinder bolting face in the next time.