First cuts - cutting a taper

Thanks for posting the pics. The tool looks good and all your angles are there. This is not easy for some folks to do so good job!

Looking at the faces of the tool, I suspect they are not flat. No, they aren't horrible but those faces must be truly flat so that they intersect cleanly and evenly. Are you using diamond stones to hone with? If not, I suggest you get some and use them. Your nose radius is small and well formed and looks even from top to bottom, though, so you did a great job there.

Try honing the tool a bit more and kick up your speed. This tool should work.
 
Here in my workplace we only use American made aluminum. Unfortunately, some one purchased aluminum from the Chech republic and the machinists had an awful time with it. We had to scrap it.
 
An update. I honed the tool a little more, adjusted the speed up more, and prob the solution- played with the tool angle as it engaged the part. I found the combination that gave a clean finish. Cut tight curly chips (albeit long ones).

I was able to adjust the tail stock and got to a close as I can adjust it with a micrometer (.001) and a DI (.0005). I have it so it’s less than .001 between both ends.
Thank you for the help so far.
Now on to hardware steel bar.
 
Aluminum and Brass are great learning metals. At least you didn't jump off the deep end and try Stainless, Titanium or Stellite.
 
So my next stumbling block is the parting tool.
I got a basic parting tool that fits my holder. 1/16” I believe.

I have mounted it In The holder with limited extension. I also inspected it for sharp edges and had to remove a burr to get the cutting tip flat on all faces.

so when I introduce the tool to the work, it more like pressing or rubbing the part with very high forces pushing the part away from me, rarely actually cutting.

I was using a piece of brass in a round section roughly 1/2” diameter.

I learned from the prior adjustment that tool height and angle make a big difference. So I worked to make sure the tool was square to the work. I also played with the tip height up and down with mixed results. I could get some cutting if the tip was below the centerline but then it would run out of material. By some cutting it would intermittently cut clean flat chips and then rub and squeal.

I tried adjusting the speed of travel and didn’t really see much difference. I stopped when every I was just pushing the work away from me.

I’m missing the secret thing to make it cut. I know it’ll be something stupid I should know.
 
Ignore your measurements... if it is rubbing, position the tool lower.
 
Using the "fish method" is usually the best on small diameter rod like what you are cutting.
 
Make sure you cut the relief angle under the cutting edge too.
 
There's not much to say with parting, except be absolutely certain of your setup.

Make a spindle center height gauge, and use that to set the height of the parting tool precisely.
Use a macinist's square to ensure the parting tool is perfectly square to the spindle.
If those two conditions are met, then you can start to work on technique, lubricating the cut, etc.

One more thing: verify that there is no slop, or other forms of deflection, in the carriage causing the parting too to move away from its perfect-height, perfectly-square position. Maybe use a dial indicator while pressing an unsharpened lathe tool into a workpiece while the lathe isn't running.
 
topcat41468 said:
Now on to hardware steel bar.
Click to expand...

I usually try to suggest new guys work with stuff that are easy to succeed with - 12L14 mild steel, 6061-T6 aluminum, brass, Delrin. Go on ebay and buy some stock. A seller called 6061dude (Paul Stoner) is one of the most reasonable, with free shipping. Email him and tell him you're a new guy looking for some practice stock. I bet he will put together a package for you.

As for your parting issues, there are at least two things to look at. First, is your tool sharpened or are you using it as received? It should have a 7-10 degree relief angle up front and it has to be honed flat on top. Second, you must be dead on center height. Too high and the tool will rub; too low and the tool will dig in. Get it dead on center.
 
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