What am I doing wrong

Well newbie , your learning start watching some YouTube's Mr Pete Tubalcain . Or barrow some shop teaching books and start reading about lathe tool cutters and shaping and sharpening of them. Carbide lathe bits come brazed on strong steel support to fit holders . Insert tools use carbide tips . With many steels when torch cut they harden and some need annealing. I had a job making hold downs for a planer for a shop I worked in . I had a lathe and mill in my garage and a bandsaw to cut stock. The company ordered the steel when I got it it was so hard even grinding was tuff. They sent it back after annealing the steel worked beautifully. I would bet about 1/4" will need to be turned before it's past the hardest edge. You can anneal it yourself usually by heating up in a coal fire then just leave it till all the coals and steel are room temperature. It's kind of a big piece to practise with but we use what we have. Find some aluminum to practise tool sharpening and making. Different metals at times need different angles and shapes.
Good luck and keep turning
 
You've already got a lot of great advice. I'll just second the "Good luck and keep turning" comment; this is a learning process.
 
neshkoro said:
If you have a mill you could cut down a 3/8" brazen carbide tool.


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You can also use up to a 3/8" tool bit directly in the lantern post bypassing the smaller tool holder altogether. Would probably need a shim (another tool bit, or piece of key stock) to bring it up to height, but it can be done and makes for a pretty rigid setup. May not be useful in the O.P. application though as I'm thinking he will need the reach of a tool holder to get to the part. On a smaller diameter though it should be do-able.

-frank
 
If a file can cut that torch slag, the lathe should be able to kind of cut it. I turned a 4" diameter torch cutout on my Craftsman AA 109 lathe. It was good and hard, and until it got below the torch cut, it was throwing sparks. The belt was loosened so the spindle wouldn't get harmed. The tool had to be sharpened three times, but HSS is cheap. In this case, I just used a broken drill bit, and worked it hard, so it was free. Finally, it was done in back gear with oil, so slow down.
 
azshadeguy said:
Okay I know that this little Craftsman Lathe is to small but still.
I have a 3/4 thick x 3-1/2 round disc.
I put the disc in a 4 jaw chuck got it centered and turn it on.The disc is a36 steel
All I had was one 1/4 inch tool steel I shaped it according to something I read.
Any way all its doing is grinding the cutter. Not even scoring the disc.
What am I doing wrong?
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Sounds like your SFM might be too fast. A36 is pretty soft so it cuts easier at higher RPMs but using a high speed steel tool will limit you. After you get your tool reground try around 25-50max SFM. That's about 25-50 RPMs at 4" diameter. Sounds slow but HSS tools were named "high speed" when most tools were high carbon steel. Some M42 cobalt or carbide will get you up there. (3.82*SFM)/diameter=RPM . RPM depends on the material AND the cutting tool material.
 
I got a 8 inch diameter X 2 inch thick steel slug to make a steady rest. It was torch cut and would not cut. I took it to the belt sander and ground most of the torch cut off. I then had to use carbide cutter and run SLOW in back gear and take light cuts to get it to the softer area past the torch cut. Once I had cut about 1/4" off the diameter, it cut fine. Torch cuts are herd to machine.
 
Mark, yep, you hit the nail on the head. Flame cut steel hardens up sometimes to the consistency almost of diamond. I ruined a complete set of carbide and HSS 1/2" lathe bits trying to turn one flame cut 6" disk round, earlier this year. Finally figured out the grinding part and easy steven thereon in!

I suppose you could anneal the other parts, if you have a lot of them. I never tried anealing flame cut material, but it seems like it would help - if you anticipate a lot of grinding . Maybe comeone else will comment if this's a good idea or not.

Glad you got it solved.

Glenn
 
On flame cut steel i usually take the first deep cut to get underneath the hard part fast, my lathe has 11KW motor so i can take 6mm deep cut without the lathe changing sound.
 
I see the disk has been flame cut. To turn the flame cut portion, you must use a depth of cut that will get below the cutting slag on the first pass or it will wipe the tip off your cutting tool.
 
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