Dick Coers
You need the expensive hard solder, very close to brazing. It is important to make a skive joint. I bevel the edges on my disc sander so I get a much longer silver solder joint. Works great. I silver solder blades from 1/4" to 3/4" and even touch up the teeth when it gets dull. Never had a joint snap since I keep it clean anduse a really good flux. Get your supplies at a welding supplier.