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
I use tons of china carbide in my CNC mill. I order about $200 worth a month and stockpile it from AliExpress. Its pretty decent some of my most used endmills are China carbide. I just try to have a lot on hand, if they break you are 3-6 weeks from receiving a new tool. Nice finish and boy can they hog some material!
Lathe guys really should learn to make proper HSS bits. Without that knowledge you really limit your abilities. Get some HSS blanks and practice with them. You will be able to solve most any or all of your turning challenges. A lot of guys also have problems with light benchtop lathes because they use big QC toolposts that hang the bit off to the left side too far causing the cut to twist the slides (gibbs too loose too?) instead of taking the cutting load straight down through to the carriage. Flimsy slides and especially the compound are one of the biggest problems with small Asian lathes. QCTP can be very rigid, but your lathe isn't.
See this home made Acme thread form bit cutting steel. See where the load is taken? Straight down to the carriage. Form bits can chatter, right? See any? Nope. Thread came out perfect. You may question why the bit is on the back side of the part. It's a left hand thread and I wanted to keep the cutting load going toward the headstock. The spindle ran in reverse. This tailstock feedscrew I made has only .002 backlash. I made it for the lathe in pictures 3 and 4. I needed a longer one so I made it.
Parting tools can chatter too. Hang your bit off to the side too far and you will have trouble parting on your light machine. See all these parting cuts in mild steel? How wide the tool bit is? Wider than your parting bit. See where the load is being supported? No problems with chatter. This part is not polished at all. Machined with hand ground HSS
Another steel part done with home ground HSS and not polished one bit. Before I case hardened it. It's a carriage lock bolt in use in the third picture above. A wrench is placed over it.