The hydraulic shaper has the same major parts as the mechanical one; however, the ram is driven by a hydraulic cylinder as shown in the simplified sketch. These shapers use 5- to 10-hp motors.
The cutting speed of the hydraulic shaper is infinitely variable by means of hydraulic controls, as is the cross feed. The reverse stroke is made faster than the power stroke because of the smaller area in the return side of the cylinder, if a constant volume pump is used. Another method is to have the rate of fluid flow increased to speed up the return stroke.
Speed and feed on a hydraulic shaper are often controlled by simple dials. Speed is read directly in feet per minute and feed is read directly in decimal inches. The cutting speed remains nearly constant through the full stroke.