How do I sharpen HSS circular saw blades. I have a collection from over the past 30 years. I use to send them out, but the local shops have gone out of business, especially since the carbide tips became popular.

The local shops probably had sharpening machines like in YouTube: Sharpening a Circular Saw Blade (http://www.youtube.com/watch?v=vXN8yOzOd3g). For HSS, the same results can be obtained with diamond hones or triangular slim taper files, a home-made saw vise, and patience. There are numerous articles online for sharpening handsaws, such as Vintage Saw's Saw Filing Treatise (http://www.vintagesaws.com/library/primer/sharp.html). The principles can be extended to circular saws to restore the teeth to their original geometry. There is also a risk with circular blades that is not present with hand saws, that if sharpened improperly the result can be a very dangerous tool to use.

Another option: Harbor Freight Circular Saw Blade Sharpener (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96687)