Mark, the meat on the reel is the distance, radially, from the outside edges (cutting edges) of the reel blades, to the radial spacers they are mounted on. When the blades have been ground down to those spacers, the reel cannot be sharpened again. It is possible to weld new blades on, or to buy a new reel, but either of these usually costs more than a replacement SB45 that still has lots of meat on the original reel. Probably at least half of the SB45s that feature in Outdoorking threads have never been resharpened and have as much meat now as they did when they were new. We have never had a measurement reported here of the amount of meat on a new reel, but I estimate it would be close to 10 mm.
One of the things Deejay will inevitably ask you to do, is to post pictures of your mower, including views of the reel, and of the chain sprockets in the chaincase on the left side of the mower. He will want to see the sprockets photographed from a point in line with their axes, so that the tooth form can be seen clearly. The next most expensive thing to do to resuscitate an old SB45, after replacing the reel, is replacing the sprockets and chains.
