If, however, only one cylinder cover can be conveniently taken off, the piece of wood will require to fit in the counterbore at the open end, and in the cylinder bore at the closed end of the cylinder; hence we make it large enough for the counterbore, and after having removed the ridge at that end we cut the length of the wood down to fit the cylinder bore, whereas if we made our rest to fit the bore at first we should require to use wedges to make it fit the counterbore.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose
Next take a piece of hard wood-oak, for instance-about an inch thick and 3 inches wide; cut it to such a length that when placed upright its ends will wedge tightly into the counterbore of the cylinder.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose
The counterbore of a cylinder is a short length at each end of the cylinder, that is made of larger diameter than the rest of the bore, so that the piston head may travel completely over the working bore, and thus prevent the formation of a shoulder at each end of the cylinder.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose