elbow drafting machine

Discussion in 'Boat Design' started by rtrg, Mar 12, 2017.

  1. rtrg
    Joined: Jul 2011
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: stratford ct

    rtrg New Member

    I saw a drafting discussion here which is why I am here. Simple question. How do I determine the board coverage of an arm type based on scale length, arm length, arm swing, and clamping spot? I see arms in the 15 to 24 inch range, and scales from 12 to 18 inches long. There are very few that have any indication that coverage is less than typical. Such as "JR", MINI, SHORT or others. I need coverage no more than 24 x 24. Probably less. A vintage DIETZGEN 1930's with arms of 15 and 20 is clamped to its own board that can be closed and stored in a draw. A3 size? Formula would be nice or a simple chart. Thanks.
     
  2. jehardiman
    Joined: Aug 2004
    Posts: 2,261
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Arm length is not as important as scale length,,,So max width is U arm +L arm+ scale. Lower corner is U arm+ L arm * sqrt (2/2)>>0.707+SCALE
     
  3. rtrg
    Joined: Jul 2011
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: stratford ct

    rtrg New Member

    please state again in more simple terms. also tell me if clamping location along top edge is or is not a factor. I would rather have short arms/scales for less coverage than the typical 3 x 4 foot or larger coverage.
     
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