I'm trying to get extrusions to merge onto one another, but the arcs don't want to comply. I've tried different ways of making the sketch, such as converting and offsetting entities, but I seem to get constant issues in different places, the arcs are supposed to be the the same length and follow the same path, but they seem to all have different results.

http://i.imgur.com/hDxyuK1.jpg

I was getting the same issue around the outside between Extrude 6 & 7, but somehow through trial and error I've managed to get them to merge. I've no idea how though.

Thanks