I'm using cheap carbide insert tools from Banggood.
For years I've been grinding my own HSS tools for my 8x14 bench top lathe, however a while back I ordered this tool set and found that they work well, even giving a pretty good finish on some 1" chrome molly tube used to make a piston shell..........
I even used them to make a 5" diameter A36 steel back plate for my 5" chuck. LOL, slow going on my relatively small lathe on the >5" diameter cuts but it was possible.........
I never dealt with this amount of "stringy chips" before (perhaps a matter of low rpm/light cuts) but I learned pretty quickly not to try clearing those stringy "razor Blades" without gloves! matter of fact, now I use long needle nose pliers to clear steel "chips" like those!
Just ordered a set for 21.00 you cant beat that!
I had picked up a set off amazon last spring, never used them before and I was worried I had made a mistake but I had to make a new cocking handle for my QB78 after busting the original off thinking it was threaded into the bolt, duh.
Any how I had some stainless rod, dont know what type. Previously I had to have my cutter super sharp and it was difficult to get the finish consistent and it took a bit of time to remove material, so I started with the hss cutter and noticed I was getting a swirly rippley finish. Rather than sharpen my cutter I dug my set out for a try. My previous experience with carbide was those brazed tip cutters and I didnt have much luck so I was a little worried.
My worries were for nothing, the carbide inserts cut better than I hoped, I removed more material faster and got as good a finish as I ever have. Actually I removed a little more than I should have in this case but I made it work lol
I left the swirl from the hss cutter on the knob
LOL, years ago I also tried those "brazed on carbide chip" tools with exactly the same result you had. I was so disappointed with the brazed carbide tipped bits using my bench top lathe that I never tried carbide again till I bought the "Banggood set" a few months ago. Brazed on carbide bits.......
I did find that the inserts tended to chip rather easily so I needed to take rather shallow cuts in steel. Good thing the inserts are cheap at less than a dollar each vs several dollars each for "good industrial inserts"!
Bolt handle looks good. Looks like chatter is causing the swirl pattern. Stainless usually leaves a very nice finish with HSS or carbide.
Yes it was definitely chattering