Shaper kinematics: In a standard shaper, which element reciprocates during cutting while the other stays stationary?
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ATool is stationary and work reciprocates
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BWork is stationary and tool reciprocates
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CTool moves over stationary work (continuous feed, no reciprocation)
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DTool moves over reciprocating work
Answer
Correct Answer: Work is stationary and tool reciprocates
Explanation
Introduction / Context:A shaper is used to produce flat surfaces by a single-point tool attached to a ram. Knowing the basic motion scheme is essential to understand stroke settings, feeds, and productivity.
Given Data / Assumptions:
- Conventional horizontal shaper with a ram and tool head.
- Work is clamped on the table or vice.
- Feed is provided by incremental table movement between strokes.
Concept / Approach:The shaper operates with a reciprocating ram carrying the tool. The cutting happens primarily on the forward stroke (quick-return mechanisms shorten the return). The work remains stationary during each stroke, except for a small indexing feed after each cycle.
Step-by-Step Solution:
Identify the moving component that executes the stroke: the ram with tool.Recognize that the work is clamped and does not reciprocate.Hence, the correct description is: work stationary, tool reciprocates.Select the appropriate option.Verification / Alternative check:Observation of any standard shaper confirms the reciprocating tool motion and fixed work during strokes.
Why Other Options Are Wrong:They contradict the basic design of the shaper where the tool, not the work, performs the reciprocating motion.
Common Pitfalls:Confusing a shaper with a planer; in planers, the worktable reciprocates while the tool is stationary except for feed.
Final Answer:Work is stationary and tool reciprocates