If there is a Joann near you, try them. Upholstery thread might be what you are looking for. Joann carries Coats & Clark Extra Strong & Upholstery Thread and several other upholstery threads.

You say it's upholstery thread and labeled "strong"? Did you compare it with regular thread? I bet it's thicker. And I bet it's thick enough; I'd just go ahead and use it. It's not the thickness of the thread so much as the close spacing of the stitches and pulling them snug.

Thanks for your kind responses. Thanks to you I rechecked the string I bought. It's nylon and reads extra strength. That was a happy surprise. I'm old, old and often need two pair of glasses to examine things. I've studied a fellow on Youtube (hand sewing with big and little doc) for doing the repair and likely will follow his lead. Can't do it for few days. I need to do my taxes. Thank goodness for Taxcut software. By the way, has Houzz taken away our ability to either edit or spell check our posts? Thanks again. Gene