You really should not give it to your long arm quilter without trimming all those loose threads. I've not had it happen to me, but I understand sometimes those loose untrimmed threads on the quilt back can get snagged up with the quilting thread and needle, causing a tear in the quilt top. Longarm needles are strong, and they stitch lightening fast, so I believe it. Mine stitches down flat flower heads on pins like they're not even there.

I use a lot of starch.

I also starch my fabrics before cutting but have found some fray no matter what you do. I try to keep the threads at bay and will cut as many as I can before I put it onto the frame but some seems to hide from you until you can't get them the easy way. I read where you can get these little devils using a very tiny croquet hook from the top side. Its about the size of your needle when you hide your thread ends. Had to do this on the last quilt and it does work. I know the hole made by the hook will shrink when the quilt gets washed so wasn't too worried about it. The problem is trying to find a very small croquet hook which luckily I found at my local thrift shop.

I use the auto thread cutter and that stops the thread tails on back as the thread ends are 1/4" long on back.

Something that might help next time. Do you have a thread cutter on your machine?. Since I have had one, I don't have strings to deal with. Also shorten your stitch length . If you are sending it to a longarmer, Please trim. It is impossible to get the threads out of the way and when I quilt for people, I hate having to leave them in because the show badly especially if they are dark threads. also, if it is a pieced border, sew a stay stitch around the quilt. keeps those edges from coming apart.

I seem to get a lot more threads than other people, I think it is because I cut so closely to the grain of fabric. But I'm also a fanatic about pressing each seam and so do a lot of thread catching at the ironing board. Usually have a bit of a ball of thread/lint/what-evers at the end of the board.

To second what Patchwork said about the stay stitching, it doesn't look like I'll have use of my friend's long arm this year -- I'm looking at other options because I already have a huge stack of unquilted tops. Anyway, I'm in the finishing stages of a scrap quit that I'm not really excited about just using it to keep busy and I am using three rows of 2.5" squares for the border. Although I usually don't bother, I figured I better add in a row of stay stitching along that outer edge, just within the seam allowance. Might be some time (ie, years!) before it's quilted down and I don't want to have to go back and fix all those little seams.

Are you talking about the fabric raveling? Or about the thread tails from where you start and stop sewing? If the later, do you use a starter/ender tab? I find using one reduces the tread trimming dramatically.

A starter tab is a small scrap of fabric that you start sewing on and then you add your fabric, as in the first piece of a chain stitch. When you trim off the starter tab, your string problem is gone. Then, add another scrap at the end for an ender tab...which now becomes a starter tab for your next seam.

When using the starter/ender tabs, as in chain stitching, leave at least 4 stitches between your patches. This will give you a space to cut and also give a stitch or two to give a lock stitch to help the seam from separating.

I hope this is clear. It's easier to show than to explain.

Oh, I won't give this to the LA as it is; it will have a lot of pressing and trimming to do first. Even so, I know that some of the frayed edges will have to stay as is. Should have starched more than I did as I was going.

My issue isn't threads from my machine but those from fraying fabric. I do spend a lot of time clipping, but, I am retired, have no physical issues to interfere, and quilt for my own pleasure and consider it part of the process.

I hate all those threads on the back of my pieced top. I use the leader & ender scrap of material and a smaller stitch length to help with the extra threads and I still get some, but not many. I trim the extra threads every time I iron a block. I admit that I am a fanatic about having a thread free back on my quilt top. It's much easier to quilt without having to deal with all those threads.

Now if the fabric is unraveling, that is another issue. I bought one piece of fabric because I loved the color and didn't realize the weave was so loose. It gave me fits. I ended up having to sew a stabilizing wavy stitch within the 1/4 inch seam allowance every time I used that fabric in the top. I only sewed on the bad piece. I learned a lot in a few minutes. The wavy tighter seam stopped the raveling and took a little bit of extra time but not as much as trimming and retrimming every few minutes. I thought about trying my pinking shears and trimming the edges but was afraid the pinking action would take too much fabric off since it was already shredding. I didn't want to have to replace those bad pieces after the quilting had been done. Thank goodness, it was a small quilt. That's one of the reasons most of my quilts these days are sewn with batiks. The thread weave is so much tighter.

Wish I had thought about the starch. I'll try that next time.

Edited to add: I always sew a stabilizing seam around the outside edge of the quilt top if there are small pieces or a lot of pieced seams. It took one time of several of them pulling apart after I got it on my longarm for me to realize what was happening. Never again.