For replacement of damaged, weak, broken or missing jack springs in most full size upright pianos. (If you're repairing a spinet or console with a compact action and shorter springs, look for the shorter springs in my eBay store, item #292018728854).  When measuring your old springs take note that the length may seem shorter from being compressed over the decades. These are made from 0.014" diameter wire, and are 1" long.  The bottom of the spring that glues into the body of the wippen is 0.201" in diameter and the end that fits into the bottom of the jack heel is about 0.159".

If you are doing spring work on a piano, do yourself a huge favor and check out my personal favorite spring tool, item #294182625249.  Hook on one end for pulling, slot on other for pushing, extremely thin, strong design perfect for working in tight spaces like a piano action.

I've been a full time piano technician for 30+ years and am glad to help answer questions before or after the sale.  My contact info is included in each shipment and you can also reach me through eBay.