Help Please with "on point" blocks
 

I,m doing on point blocks for the first time. I,m making a table runner.
My question is, when you bring the point of your square and the triangles
together to sew, I,m getting lumps or puckering.
Is there a trick to doing this?
Thanks in advance.:(

Can you post a picture? There shouldn't be pickers. I just imagine what's wrong without seeing what you're doing. Sorry. I'll look back to see if you can get a photo up. Maybe someone else can figure it out.

Sounds like your stretching a bias edge. Spray starch the setting triangles before sewing them to the blocks making sure you don't stretch them as you press.

Perhaps your setting triangles are the wrong size? I made a quilt and put the blocks on point. I used Bonnie Hunter's guide to figure out the correct size for my setting & corner triangles. http://quiltville.com/onpointmath.shtml

You can always trim some of the seam allowance a tiny bit to remove excess bulk at the point. Also consider pressing your seams open.

Are you doing yours in rows (on the diagonal) ? http://quiltbug.com/articles/on-point.htm

I always make my blocks a little bigger than the pattern calls for. your outside edge should be straight of grain. I normally sew any bias edge on the bottom to allow the feet to feed the fabric thru the sewing machine correctly. Learned that from Eleanor Burns.