Formulas McCunn Sleeve

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This section describes how to draw a basic sleeve block using the McCunn System[edit | edit source]

Figure 1

Figure 1 shows the basic reference lines and other major lines used in constructing the main portion of the sleeve.

The instructions in this section will describe the process to use formulas in the Seamly2D program in Draw mode to construct a scalable sleeve pattern.

To begin creating a sleeve pattern using the McCunn method, open Seamly2D. Figure 2 shows the window that will be displayed when Seamly2D is first opened before pattern creation has begun.

Figure 2

The basic window shown in Figure 2 will remain visible during the rest of the pattern creation and until the Seamly2D program is terminated. Click “Measurements” and select “Load Individual” from the drop down menu. Load the measurement file you plan to use. (The measurement file would have been created previously using the TAPE program and include the following measurements as a minimum:

  • L01 arm_shoulder_tip_to_wrist_bent
  • L16 arm_shoulder_tip_to_armfold_line
  • L11 arm_upper_circ
  • D04 hand_palm_circ
  • L02 arm_shoulder_tip_to_elbow_bent)

Click “New” and enter a name for the pattern piece. Select the unit measure that you wish to use. Click OK to create the pattern piece. Figure 3 illustrates the window that will pop up after New is clicked and will allow these selections to be entered.

Figure 3

Each time Seamly2D creates a new pattern piece a base point is created. Because “McCunn-basic-sleeve” is the first pattern piece in the pattern file, the base point is labeled “A”.

Figure 4

McCunn method - step 1) The first line, which is the Sleeve Centerline (shown in Figure 1), may be seen as a line from the shoulder point to the wrist. Draft this line using the “point at distance and angle” tool.

That tool is found on the Seamly2D Point sub menu. Click on point A and drag the rubber band line in a downward direction. The angle and distance need not initially be precise because a window (as shown in Figure 4) will pop up and provide the opportunity to make adjustments to the values.

Use the Angle data entry box on this window to ensure that the angle is 270 degrees exactly. An angle of 270 represents a vertical line in the downward, or "south" direction.

Select a color other than black to indicate that this is a reference line and not part of the final pattern outline. (In this example, golden rod is chosen for the reference lines). Lines which correspond to the final outline of the pattern will be drawn in black.

The length of the line is represented as a numerical length (which is a result of the length the user dragged the rubber band line). Delete that numerical value and click on the function icon. The function icon may be recognized by the label f(x).

Figure 5

As a result of clicking the function icon, a formula window will appear (as represented in Figure 5) to provide options for creating a formula.

Options for data that may be included in the formula include the items listed on the left side of the window under the words Input data. In this case, a measurement will be chosen, specifically “arm_shoulder_tip_to_wrist_bent” which corresponds to the measurement called “arm length” in the McCunn method.

A point is created at the wrist end of this line and is automatically labeled "A1".

Figure 6

McCunn method - step 2) The next reference line is called the biceps line (as shown in Figure 1).

The line is drawn perpendicular to the Sleeve Centerline at a point that represents the length of the sleeve cap. First the “Point at distance along line” tool will be used to mark the point that defines the edge of the sleeve cap.

Figure 6 illustrates the window that will pop up for data entry.

Figure 7

Click on the function icon to bring up the window that allows the data entry. Figure 7 illustrates window that will appear to provide options for entering the formula to locate and mark the point along the Sleeve Centerline that defines the edge of the sleevecap. Click on “Measurements” under "Input data", then double click on “arm_shoulder_tip_to_armfold_line” to use that measurement to define the point.

Figure 8

Now that the edge of the sleevecap has been located, the “point along perpendicular” tool will be used to draft the bicep line. A perpendicular line which is 1 1/2” plus half of the biceps measurement will be drawn on each side of the sleeve centerline. Select the “point along perpendicular“ tool, then select point A2 as the first point of line and point A as the second point of line. The Help Sentence will indicate the time to select each point. The “point along perpendicular” window (figure 8) will show the formula. It will also show that the label A3 was assigned to the point created and that the “additional angle degrees will be left at the default value of 0 degrees. That corresponds to the line at a right angle to the vertical Sleeve Centerline to the left side.

To construct the formula for creating a line of the required length, double click on the f(x) label in the “point along perpendicular” tool window. Double click on the “arm_above_elbow_circ” measurement from the measurement table then use the keyboard and arrow keys to complete the formula to look like this: 1.5 + (arm_above_elbow_circ / 2). The 1.5 (or 1 ½) inches included in the formula represents the basic fitting ease as described on page 72 of the 1977 revised edition or or the Ease as described on page 80 of the 2016 second edition of the McCunn book. Figure 9 shows the formula data entry window.

Figure 9

Click “OK” to exit the data entry window and click “OK” to exit the “point along perpendicular” tool window. You should see points A, A1, A2, and A3 along with the sleeve centerline and the left half of the biceps line. Figure 10 shows how your Seamly2D main window will look after steps performed so far in this tutorial.

Figure 10

To create the right half of the biceps line, you will again use the “point along perpendicular” tool. The steps are the same, with the exception that the point created will be labeled A4 and the large blue arrows will be used to change the “additional angle degrees” value to 180. Figure 11 illustrates the point along perpendicular tool window which reflects the appropriate values.

Figure 11

Follow a similar procedure to create the Wrist Line. Again, you will use the point along perpendicular tool and create the line in two halves. Use point A1 as the first point and A2 as the second point and use the hand_palm_circ / 2 as the formula for the length of the line. The two halves of the wrist line will be drawn in black because they correspond to lines on the final sleeve pattern. The details of constructing the left side of the Wrist Line are not shown in this tutorial because it is so similar to the procedure used for the Biceps Line already covered. Figure 12 shows the window from the last step in the process of creating the right side of the Wrist Line.

Figure 12

Each of the two Arm Seam Lines will be constructed using the “line between points” tool. This tool is grouped under the heading “Line” in the tool menu. Select the “line between points” tool and pay attention to the Help Sentence to know when to position the cursor over points A3, A5, A4, and A6 respectively. One line will be drawn between A3 and A5 and one will be drawn between A4 and A6. Figure 13 shows how the Seamly2D main window should look after these lines are drawn.

Figure 13

It may be helpful to review figure 1 from this tutorial and figures 146 and 147 from the page 72 of 1977 edition or the figures on page 80 in the 2016 second edition of the book How to Make Sewing Patterns at this time.