Both have their uses.
For example,Ivorine 4 simply can't be cut with anything BUT carbide.
HSS cuts cleaner on certain materials,leaving a better finish quality.
Both can be reground any way you want,but it requires time,skill,and a point in the right direction if you've never been shown how to regrind properly.
A skilled person can make carbide scary sharp. The cheap brazed cutters can be quite good,but often they have to be completely reground out of the box.
The problem I have with indexable cutters is the cutter's body itself.
I too bought one of those cheap HF sets,and every one of them is made poorly enough that the insert has slop in it,and you can see the insert move if you change direction with the lathe carriage. No amount of torque on the screw changes it either.
I do have a Micro 100 SDJCR that uses a DCMT carbide insert. I bought inserts with just a .007 nose radius,and they don't even cut leather,they just push it out of the way. I just use them for metals now.
Maybe a different insert for that holder would produce a better result.
I am a huge fan of the Micro 100 brazed carbides though.
For facing cuts,I turn my toolpost just a little towards the face so it has relief both ways. Tommy D.
Good writeup.
I generally use HSS for lathe bits (carbide for router bits and boring bars). Its easy enough to resharpen. I have several of the same shape tools. I never let them get too dull so they are easy to sharpen. Take a couple thou off and good as new. When they dull I put them in the the regrind box and resharpen them all at the same time.
If you try to use the square bits right out of the box you'll run into problems. I'd have to look at my grinder but I believe my angles are set for 10 degrees. You want a rake angle on the top (it angles back away from the cutting edge). Your cutting face will be straight (angled down from the top edge) and the front end angled across and down as well, again mine is about 10 degrees. The angles are for clearance. I generally leave mine with a sharp point. You may want to put a tiny radius on the end. You can try it on the grinder but its really easy to take too much off. I usually prop the bit up at an angle and run a stone around the point keeping the 10 degree clearance angle. The radius causes a little more pressure but it holds up a little better and also leaves a nicer finish. You really only need a radius of maybe .005 (about 1/2 the diameter of 2 hairs)
You want a flatter rake surface for hard materials but for softer materials you want decent angles for shearing, clearance and chip breaking. Hard to remember exactly how this works but essentially carbide is for pushing the metal off where HSS is for shearing it off. So for plastic you want decent angles, if you get them in carbide it should work just as well and hold up better.
A little note about regrind.
Form Tools: Say you make up a bit to cut multiple radii/angles for Joint Protectors. You only flat grind the top of the bit, you generally do not regrind the radii (the face of the tool).
Cutting Bits: (Left, right, etc cutting tools). You don't grind the top of the top (the rake angle). You only grind the face and sides. If you're using 10 degree angles, grinding .010 off the face only drops the height down about .001 so you probably don't need to reshim to get the center.
I love the micro 100 tools as well. That is some tough-a$$ carbide. All my BBS are Micro 100. FYI, there is nothing wrong with brazed carbide tools as long as they are good tools. Don't buy crap. Note, all carbide is not the same. Micro 100 is not the crap you will find at HF.
Those indexable cutters from HF are junk, don't waste your money. The problem with a lot of the indexable carbide/ceramic insert tools is that they are made for metal. So even though you see a chip breaker on the insert (that radius dish along the cutting edge) the top cutting edge of the insert is flat. For cutting metals that is fine but for wood and plastics it will try to push the wood/plastic away. They do sell inserts that will work but you have to look. Call one of the tooling companies and tell the Rep what you're looking for. The style inserts Joe Barringer used in his videos look to be the ones you want, nice shearing action. If you bought his videos he may tell you the model insert he uses.... but he's certainly under no obligation to do so. Buying something may grease the wheels of his kindness
Buy GOOD tooling. If MSC, Enco, MMC, etc. sell the tool you want for $10 and the cutrate place only wants $3 then guess what, they are probably crap.
One last thing. MAKE SURE YOUR BITS ARE IN LINE WITH THE CENTER OF YOUR WORKPIECE. The cutter tip should be dead center or a little lower. Lower as in a few thousandths NOT 1/16". Chuck up a dead center and bring the tip even with the point. I use an eye loupe now... getting too old to see small stuff.
