# Exercise 7-14 The Link in rhino manual

I am stuck on how to do this exercise…I realize one needs to make a series of circles for the construction, but for the top section I don’t know where to place the circles, there’s no distance for that area of the diagram.

Either I don’t understand what you mean but there’s an angle and a distance from the center of the right hole which give you what you need to draw this

There’s no distance for the top section, it just says the angle of 30 degrees

R3.88 is the relevant distance.

Oh I thought that R3.88 indicated a radius for something. What does the R stand for in this case?

It is the radius of the upper hole base arc.
With the radius, the start angle and the end angle, this is completely defined.

Ah sorry I don’t get it…
Using the right circle as a reference point, I would draw an angled line of 30°, but I don’t see how long that line should be from the given information

Hi Leon - the circle at the top end of the arc-shaped slot is 3.88 units away from the lower right circle, at an angle of 30 degrees from the vertivcal. 3.88 is the radius of the centerline of the arc shaped slot.

-Pascal

Hi Leon,

Here’s an illustration showing an order in which you could draw lines to complete the brief.

White lines are temporary construction lines, black lines are final. Putting construction lines on a separate layer means you can keep them in your model for future reference but turn off their visibility.

• Mark the two bottom centres: 1 & 2.
• Draw the end arcs to the specified radius: 3 & 4.
• Connect the bottom ends of the arcs: 5.
• Connect the top ends of the arcs: 6.
• Draw a line at the specified angle from 2, long enough to pass through the slot: 7.
• Draw the second angled line: 8.
• Draw an arc representing the centre line of the slot: 9.
• Draw an arc of the specified radius centred where 8 and 9 intersect, starting and ending on 8: 10.
• Draw two arcs centred on 2 and starting at each end of 10: 11 & 12.
• Use `Arc, tangent, tangent, radius` to connect 6 and 11 (select those lines for the tangents then specify the radius at the prompt): 13.
• Use the same technique with 6 & 12 for the second fillet: 14.

You can complete the model by adding the remaining lines from end to end and adding the remaining geometry. Don’t forget to turn off the construction layer.

HTH
Jeremy