How to cut a convex fence.

When I moved into my house the back yard was fenced in on 3 sides.  I've been working on completing the fourth side since last July.  (Obviously I haven't been in a hurry to get it done.)

I can dig holes and put in posts.  I can screw on horizontal 2x4's and vertical pickets.  But, when it came to cutting the convex arch I was baffled.  I tried creating a cardboard template from one of the other sections of fence.  This worked OK for two sections, but I wasn't total pleased with how it came out.  The real problem with the template is that it's a fixed size.  I have sections of fence that are shorter than the template.  So that wasn't going to work.

I search Google for how to cut a convex fence and didn't come up with much.  I spent some time with string and placing pivot points and tried to figure it out that way.  Nothing I attempted was working.  Finally, a neighbor mentioned something that seemed so simple.  He suggested I put a nail on each post and use some flexible molding and just lift it in the middle.  Duh!  Why didn't I think of that.

I didn't use molding.  I bought a 10' section of 1/2" PVC pipe.  (It's the same stuff I used for one of my drip irrigation projects.)  I cut a piece of 2x4 to be 9" in length.  That gave me the proper center height.

I placed the clamp so the PVC would be located at the right height on the first picket.

I drew the arch in two steps.  It might just be me, but I thought that the extra pipe extending beyond the clamp caused the arch to have a somewhat funny shape.  I probably could have cut the pipe.   Instead I just slid it so the pipe was just under the clamp on one end (see the picture above) and then drew the arch on that side.  Then I slid the pipe so it was just under the clamp on the other side and drew that half of the arch (compare the picture below to the picture at the top).

Then I grabbed my handy-dandy cordless circular saw and a coping saw.  I did most of the cutting with the circular saw.  Because of its size I wasn't able to use it to cut the last 3 pickets on either end.  The horizontal 2x4 was in the way.  For those pickets I used the coping saw.

I am very pleased with the results.

I cut the right most section using a cardboard template.

Now I just need to get more pickets, finish building the fence, cut the rest of the arches, and then stain it all front and back.