I will keep pinning as well.

That is the way we held our long seams at the sewing factory.

I totally agree with you! Especially when sewing the binding to the top. I only pin a foot at a time as I go. It lays completely flat and I've never had a pucker or wrinkle that way.

i go both ways on this too, pin or not, but thank you for sharing this tip will try it soon

To some extent, I think it depends on the specific sewing machine also. I have seen machines that seem to feed very unevenly, with the feed dogs pushing through much more fabric than the presser foot allows. My Bernina, even though it does not have the accufeed feature (built-in walking foot), seems to feed very evenly. That may be why I've never had much of a problem with uneven feeding of strips or "bending" of long strips from stretched fabric.

So, the two-handed strip feed may work better on some machines than others. It may not all be user-dependent!

I haven't pinned a long seam for more than 30 years. Never stretched any fabric cut on the grain and I haven't bled on any fabric for a long time. Knock on wood. froggyintexas

I found this demo on how to do this, but you have to watch closely what she does with her right hand.
http://www.youtube.com/watch?feature...&v=KB6QUWcOcOY

I have enjoyed reading all the comments this has brought. It was interesting to find out this is an "industrial" way of sewing long pieces together.
The lady who told us about this just off handedly said "you should be doing all your seams like this"--that's when I realized I wanted to update my methods.