1st attempt on lathe

[n9jcv]

So I spent 3 hours on a metal lathe for the 1st time in my life. I have some wood lathe experience.

This is a big old lathe, sheldon that I suspect to be 50-75 years old. I first put a piece of steel about 1.25 inch round in the chuck.

1st thing i did was grind the parting/cutting tool. Then i cut the end off because it was not square. This went ok. I had the tool slightly below center though and it did not seperate. Then I had to adjust and cut some more. How do you find and place exactly center? How do you ensure it cuts 90 degrees/perpendicular, otherwise you end up with a convex or concave shape.

Then I ground my first bit. Basically a triangular point. I turned down the end of the stock taking about 4 thou at a pass. I tried speed from 300 to 500.

Below is the result. Basically very poor. I must be doing something wrong. Basically looks like fine screw threads. Not smooth. The bit was sharp. I did use a bit of oil as well but that did not change my results. Seemed to be a lot of squeaking type noise even shaking ?????

Any help is greatly appreciated.

 

[Rooster]

Greeting's, you should read South Bend's- How to Run a Lathe or Atlas's- Manual of Lathe Operation. They both give the same invaluable information.

 

[mmcmdl]

Speed is way too slow and the reason the result looks like a screw thread is because of your tool grind . You would need a radius on the tip if you prefer to use this grind . Better yet though , grind your tool to turn and face . I'm sure there are pics of the correct grind on HM . Have fun and experiment different grinds . As far as the cl of the lathe , easiest way is to eyeball it up with a center in your tailstock and make final adjustments after cutting . Your crossslide assures a perpendicular surface if you have the needed side clearance on your cutoff tool . Hope this helps !

 

[Z2V]

Mikey started a great thread on tool grinding,
https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/page-4
It’s long but the meat and potatoes start on page 4

 

[Uglydog]

Really cool!!
Thank you for posting your first swarf with us.
Looks far better than my first!!

Everything above!!

Remember stick our from the chuck should not exceed approx 1.5x the diameter.
Looks like you are within that envelope.
I like to work farther from the head stock. Especially when I first started.
You'll understand why should you ever crash your lathe.

Do the jaws on your chuck reverse 180degrees?

Daryl
MN

 

[markba633csi]

Just need to practice your tool grinding skills: rake, clearance, etc.
also try drilling a hole in the end of your piece
Mark

 

[Nogoingback]

There are a number of ways to adjust the tool to the spindle centerline.

One way is to place a dead center in the spindle (before the work goes in the chuck) and adjust the tool height to the
point on the center. I've also done the same thing with a center in the tailstock. If the work is already in the chuck, you can place a small strip if metal ( say 1/2 by 2") between the work and the tool and gently run the carriage in until the piece is held between them. I the strip tilts one way or the other, the tool height needs adjustment. If it's vertical, you're on center. There are other, more accurate methods, but either one of these should work fine for you. If you face off your part
and there is a tit left , you can readjust tool height until it faces off cleanly.

 

[Martin W]

Good job. Keep up the good work. Try honing your cutting tool on a stone also for a better finish. You can also hone a slight radius on the end of the tool
Cheers
Martin

 

[n9jcv]

Thanks everyone for all the helpful suggestions.

I still have a question on the cut off tool and it being perpendicular. I understand the cross slide is perpendicular to the piece, but the tool holder will turn 360 degrees. How does one ensure it is at a 90 degree angle thus completely perpendicular. My thought is it could be plus or minus a degree and I will have a concave or convex face, perhaps I am not explaining well.

Thanks

 

[n9jcv]

Also about the chuck. I need to learn so much more I know. And I will take a class at the college, but I just missed this term and have to wait until next term. But in the mean time I still want to learn and practice.

Anyway the chuck. I am not sure if the jaws remove and reverse. Would I just loosen them all the way til they fall out and re-insert?

I also was turning a slighly larger piece, not pictured, It was say 1 mm less diameter than the center hole in the chuck, probably 1.25 or 1.5 inches. I was able to squeeze it in, and then tighten the chuck. But if it were 2mm larger it would not fit, yet the other inner set of jaws would not compress far enough to hold this piece. So what would you do in that situation?

Again a 1000 thanks
b