Does anyone know if its possible to free motion quilt with one of these machines? Thanks

Yes it is possible. Take all the pressure of the pressure foot and it will free motion quilt or you can use a darning cover if you have one this will cover the feed dogs. I have free motion quilt with mine many times.
Glenn

Great! thank you

I am just getting ready to try the magic bobbin washers on my 66's to see if it helps keep them from looping on the backside, some say they don't work some say they do, I will let you know. I love the red eye 66's, rich looking machine.

I think you have more of a tension problem than a bobbin problem.
Glenn

Thanks for the info Glen
What would you suggest that I do to the tension, top or bobbin?

I think those Magic Genie Bobbin Washers really are magic - but so far, only in the vertical bobbin machines.

They don't work in the 66, 201, 301, 401, 403, 500 or 503 - all of those are horizontal bobbins and there is just enough "height" in the washers to push the bobbin up and allow the thread to sweep around and get hung up on the bobbin with every pass.

They virtually eliminate the tiny little wads of thread on the backs of quilts, though. I won't use a vertical bobbbin machine without one.

If you have big loops on the underside, it means that your tensions are out of balance - there is not enough tension on your needle thread compared to the bobbin thread. Try adding tension to the needle thread about ten degrees at a time until you're getting a nice even stitch on both sides of the quilt. :)

Hi Vintage Seamstress let me know how it goes