Honing Carbide Inserts
Hi, im still rather new to machining. I recently messed up the tip of a few carbide inserts that i was using. I have a bench grinder with coarse and medium wheels and a medium and fine honing block.
I have read my books on how to sharpen tool bits and gotten that basic process down. I was wondering if anyone can tell me if a magnification device is requred to inspect the tools edge or will normal vision be sufficient? If magnification is required what power do i need? I have a small handheld 60x-100x that i got from radio shack and it is a pain to use.
Also does anyone have any closeup pictures of what the tools edge should look like when fully sharpened?
Are you refering to actual insert tooling or cemented/brazed carbide tools? With the latter the carbide chip is not removable from the shank without a torch to melt it free. This kind of tool can be ground using a "green wheel" on your grinder with a rather poor microscopicly chipped edge, which can be improved with a diamond whetstone or hone. Better yet is a diamond wheel on a carbide tool grinder with a diamond hone.
If your using replaceable carbide insert tooling, the inserts are designed to be tossed after the cutting edges are gone. I have ground inserts for special applications, but they never hold up like the originals. You can get a pretty good look at the cutting edges with a low power jeweler's loupe.
Toss the inserts in a can , when they are dull, but remember that they bring over 7 dollars/lb. so they are well worth saving..
In a pinch, you can grind an insert. I know there are few people on here that swear by it(past threads).
Its not my favorite thing to do, but I l have done it, I'm sure I'll do it again.
Need a sharp square corner, grab a beat up insert and grind it. Part off tools, when not running balls to the wall production, get this crap the hell out of my hair jobs. I have no problem with it. Need a .040 square corner groover and all you have is a .040 radius groover, grind it.
2am on a nasty nasty job, run out of inserts, start grinding.
Shawn, just sort of follow what is there already. You can alter it a bit, if you are running a TPxx insert with 11 degrees relief, you usually don't need the full 11 degrees, so you can grind it at one or two, unless on a boring bar. I wouldn't grind the top of the insert, just the sides, or just the radius so you can get back to cutting.
You don't need a fancy magnifier, most of the time you can see it, sometimes I'll pull out the head gear with the flip down magnifiers on them, $15 big deal.
If you are just trying to be cheap, then buy some new inserts, and figure out why you toasted the ones you have. Cheap inserts, wrong inserts(for material/machine rigidity/cut depth etc...), wrong surface speed, wrong Depth Of Cut, too much feed, too much overhang, loose gibs, over/under center.