Thanks, Rhonda! Very interesting about pulling those stitches out....

Using the Swirl method, mentioned by a number of posters, works so well. It makes you heart beat the first time you remove a couple of stitches, but the results is simply amazing, flat an you will have the colors going as directed. It may take a couple of blocks to get this technique to feel natural, but it Does work. I made a double sized quilt that was all pinwheels, I had lots of swirling and a beautifully flat, no lump quilt. :)

I swirl and whack with a hammer on wooden block...I have used a steam iron....that didn't do much, but using the hammer fixed it.

Whenever I have any block with many converging seams in the center (Pinwheel, Lemoyne Star, Kaleidoscope, etc) I do not stitch my final seam edge to edge all the way across. Instead I start at the center, stitch to the edge, remove the block, flip it and then do the other side. This technique offers several advantages.
1. It allows you to start at the multiple seam intersection so no need to remove a few stitches to swirl the center
2. It gives you better control of how that center comes together because you are starting there so those center points all line up correctly without any getting chopped or off kilter
3. It allows you to press that center seam in two different directions to help avoid bulk and lumpy build up.

Joining the units of block this way greatly improves accuracy and greatly reduces frustration. So worth the few extra seconds it takes to sew the seam in two passes instead of one.

Edyta Sitar recommends doing this. You can google her tutes for 8 pointed (Lemoyne) stars to get a visual of what I am talking about. She also describes the technique with lots of photos in many of her books. I learned it from the Scrappy Fireworks book.

Feline, is this the video you are referring to? https://www.youtube.com/watch?v=A07cv78uXpY

yep, hammer works great. I put a towel over fabric and maybe a little spray starch and hammer til flat. Works fine.

No, there were several out there which is why I didn't post a link but the one from FQshop that is about a beginner 8 point start at about the 10:30 mark is where she starts discussing it. https://www.youtube.com/watch?v=qV-LPJpl0JU

This is a good way to get rid of the lump,

Was thinking about this yesterday when I was showing my friend one of my baby quilts that has that same sort of star seam.

If you are going to be doing the quilting on this, I'd avoid trying to go over the lump. It will (most likely) cause you problems again with the lump.

Those centers like that remain pretty hard and lumpy.

With something like this I will press in a clockwise rotation. That does help in the long run. I do press in the halves before sewing the block together with steam to make it lay straighter.