11-point Divider

by nmartin in Workshop > Tools

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11-point Divider

complete1.jpg

I was working on a project (alcohol stove) where I wanted to divide a length into multiple equal parts. My past experience from navigation had me looking for a set of 11 point dividers to buy, but the price was prohibitive (a couple hundred $ for a small metal set). Thus I thought to build a set using Autocad for design and a K40 laser cutter.

Supplies

Materials:

1/8" or 3mm Birch plywood. 4" x 8" is more then enough

1/16" diameter, 9/32" long copper rivet, 37 total. Normally sold as pack of 50 for a little more than $5.

Tools:

Laser cutter

hammer, center punch, and hard surface to set rivets

Cut the Parts

cutting.jpg
parts.jpg

The attached dxf files are labeled by the part length (2,3,5,8, or 12 units) and and pointed end or not (not = "-"). You will need to cut out 1 each (1x) of the 2, 5, 8, and 12 unit length parts, and 7 each (7x) of the 3 unit length parts, or use the dividers2.dwg file for a complete set of parts. I also recommend cutting out spare parts just in case up need then later

Putting the Parts Together

rivet test.jpg
first rivet.jpg
rivet3.jpg
rivet2.jpg
rivet4.jpg

Initially, I tested out different types of fasteners. The 1/16" diameter by 9/32" long copper rivets work well with the 1/8" plywood and look nice. They were also about half the cost of the other recommended fastener which are nylon screws, which were cut down and melted.

Starting from the two 12 unit length pieces, rivet the wide ends together. I did this by placing the rivet in the end holes with both pieces together and using a center punch to expand the hollow center of the rivet then turning the pieces over and tapping lightly with a hammer with the rivet against a hard surface (anvil) to further expand and flatten the rivet.

Continue by adding the 8 unit length pieces, check the positioning of the pointed versus round end parts are on the same plane (all pointed parts on top or bottom when riveting) and the slope of the pointed ends are consistently on the same side (left or right side). Using the pictures as a guide, work from one side to the other riveting on the remaining parts.

Test Them Out

complete3.jpg
complete2.jpg

I open and close them by gently pulling/pushing on the opposite sides of the points.