Be sure to vile a small bevil (ramp) to the edge of the mast section. The vernier measurer (micro measurer) will maeasure the wallthickness some 10 mm away from the edge anyway. The saw cut itself (shards) can easily add a few tens of mm wallthickness and 0.15 mm difference is well inside that range. I had that problem just yesterday when keeping apart a tube with 2 mm wall and a tube with 2.5 mm wall for my landyacht mast. I didn't think the shards would pose a problem with (a large) 0.5 mm difference in wallthickness but I must admit that I was wrong.
