Thursday, May 9, 2013

Exhaust Manifold Form Block


To make the form block for the manifold I started with a template for the cut out shape.  Obviously I could have just drawn the shape directly on the particleboard.  The block is made of 3 layers, so this saves some drawing time and errors.  The main reason I made it was to use as a gauge to check the opening with.  I wanted to assure I get the cylinder spacing and size correct.

The finished template was used to draw the opening on the pieces of 5/8" particleboard.


The opening was cut with a saber saw to avoid weakening the board by cutting in from the edge.  The only problem is you have to be real careful to avoid applying some side pressure and causing the blade to tip to one side.  Once the opening was cut the edges of the hole were filed to get a tight fit to the template.

This first layer will be used as the center layer in the block.


The top and bottom layers were cut slightly undersized and were not fit to the template.

Alignment holes were drilled in the corners so the stack could be bolted together.

To match the top and bottom layers to the middle layer a straight router bit with a guide bearing on the end was used.  You just adjust the depth of the router to the middle of the center board and run the router around the edge.

Much easier and faster than trying to make 3 matched boards by hand filing.


The edges of the main sections of the shells have a 3/8" radius between the pipe and the flange.  Another router bit was used to radius these areas.

The flange hole has square corners so the transition from 3/8" radius to square corners was hand filed.


The 3 layers were then glued together using the bolts to align them and lots of clamps to get good pressure while the glue dries.


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