I can't use a metal thimble either. What I have found that works the best for me is the rubber fingers you buy at an office supply store. Underneath the rubber finger on the spot where the needle sometimes goes through the rubber I place a small oval thing-a-ma-jig called a Thimble-It. It is so much more comfortable than either a metal or leather thimble. The Thimble-It is made by the Colonial Needle Co. They are $4.95 for 64 ovals and you can use them several times before the adhesive wears off. Find them at colonialneedle.com. The rubber fingers come in boxes of 12 are are usually less then $2.00 a box.