I.  Connecting two points

Remember as you read this that I make no claim to be an expert. I am simply a competent journeyman, and the methods I use are my own. Others may use different methods, and those are probably as good as mine.

I was taught most of my basic layout in the late 1950’s by a journeyman Millwright who was dirty, smelled bad, and was constantly spitting tobacco juice on everything and everybody near him. He was almost illiterate, and spoke like an illiterate, and cursed constantly. His only saving grace was that he knew what there was to know about layout, and was willing to teach me. I will always be grateful to him for the knowledge he imparted to me. His teaching was the basis for me learning more advanced layout later and earning my living doing layout work. A good portion of the pipe in the mammoth California Water Project was laid out by me.

Layout is accomplished using one or both basic methods: Centerline layout and/or baseline layout.

In centerline layout the center of the object is found and a line is drawn through it, usually vertically. A horizontal centerline is also often used in conjunction with the vertical line, or alone. Measurements are mostly made from these 2 lines.

In baseline layout a base line is established, usually on or along one edge of the object. Another baseline can be established, usually at the end of the object, and this line is usually perpendicular to the first baseline.  Measurements are mostly made from these 2 lines.

Notice that I said, “mostly made” from these lines. You can use any combination of base lines and center lines to get the job done. There are no hard and fast rules, just guidelines that you may or may not choose to follow.

Lets take a look at a few simple layout methods.

One of the first things I always tried to teach my apprentices was how to connect 2 points with a straight line. Here they are points A and B.

The first thing to do is put your pencil point on one of the points as shown below.

Bring the straightedge up to the pencil, then use the pencil (or scribe) as a pivot point to move the straightedge to the second point.

Then draw the line.

I have watched many apprentices trying to align the straightedge with both points at the same time, without using the pencil for a pivot, and it is always a struggle. This way is quick and accurate.

December, 2005

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Copyright © 2005 James Thompson.  All Rights Reserved.