Exhaust Manifold Flanges - Inlet Side Cut Fixture

The 2 side cuts for the inlet openings needed a fixture to get a straight cut and to hold the torch at an 18 degree angle while making the cuts..  For the top and bottom cuts the angle is formed by tipping the plane of the cut 18 degrees from perpendicular while holding the torch perpendicular to the flange in the plane of the cut.  For the sides the 18 degree angle is in the plane of the cut while the plane of the cut is perpendicular to the flange.

 Just like the other fixture I'm using the vise to hold the fixture so again I started with a piece of steel angle clamped in the vise.  The flange sets on the angle while cutting.


I cut 2 slots in the piece of angle to provide clearance while making the cuts.  I left the center piece so I can clamp the flange in place while cutting.

 To locate the flange for cutting I made a pocket for the flange to set in.  I had wanted to use a pin in the bolt hole as a stop side to side like I did in the other fixture but there wasn't enough room.  The side cuts are too close to the bolt holes.


The pocket will get held to the angle by the screws which hold the roller guides in position.

 As with the other fixture, the side roller guides are pieces of 0.050" steel with slots for the screws to allow side to side adjustment.

In this case I will use the left hand guide for the cut on the left side of the flange and and the right guide for the right side cut.

 With the other fixture the the side rollers are adjusted to tip the cutting tip to the side.  With this fixture the front (side) rollers are adjusted even to hold the tip square.  To get the 18 degree angle the rear roller needs to be 1.71" lower than the front rollers.

To do this I made an "L" shaped table which is attached to the back of the angle.  The vertical slots allow the height to be adjusted to get the 18 degree angle.  The side slots allow the side guides to be adjusted to position the rear roller.  They also hold the 2 pieces together to form the table.

 As with the front roller guides the rear roller uses the left hand guide for the left side cut in the flange and the right guide for the right side cut.

I need to adjust all these movable parts, wait for the current snow storm to end and then try this out.