Tips On Turning Hard Steel On Lathe With Cemented Carbide Toolbits

[Pmedic828]

Thanks to all - I will look into a 80° diamond inserted tool. Any suggestions for someone who is on a limited budget and a small 2 hp lathe. I managed to cut down 6 of these monsters but the person that I was turning them for did not want to pay more than $2 each to have them turned down so I didn't take the job!

 

[benmychree]

In my humble opinion, cemented carbide tools are not satisfactory for serious machining. They once were all that was available, but soon were replaced with index-able inserts of varying shapes. Use a triangular insert with a small radius and undercut the shoulder to eliminate the radius.

I think that the term "cemented" carbide is an archaic term that refers to the method of manufacture of the carbit bit only, not the method of holding them to the shank; when referring to tools such as the writer refers to the correct term is "brazed tools" In that sense these would be cemented carbide blanks brazed onto steel shanks. I quite agree that insert tools are far better and more convenient than brazed tools, which possess perhaps greater durability in the case of interrupted cuts than insert tools. The shop where I apprenticed back in the early '60s used lots of brazed on tools, up to 1" square shank size, and they would hold up to interrupted cuts much better than insert tools, but lots of time wasted in re sharpening them. I think most beginners should learn to grind HSS tools and learn to use them before graduating to carbide for those jobs that require their use, such as hard and abrasive metals.