Newbie

[Rob B]

Atlas 10F, I have inserted a solid to 1 1/4"round aluminum piece to turn down. Each time I make a pass, I can go back and remove more material each time without making any adjustments on the feed.

 

[JimDawson]

Atlas 10F, I have inserted a solid to 1 1/4"round aluminum piece to turn down. Each time I make a pass, I can go back and remove more material each time without making any adjustments on the feed.

Sounds like your tool bit may not be as sharp as it could be or maybe the geometry is not correct. Maybe not enough front or side clearance. Try some steeper clearance angles and maybe lower the tool height a bit.

 

[Charles Spencer]

How is the work being held? This might be caused by run out.

 

[brino]

Hi Rob B,

Welcome to the group!

You don't say how it's being held; so I'll guess in a chuck with no tail-stock centre.

Check the chuck for "bell-mouth" where the jaws are further apart at the tips than the base.
With each pass of your tool bit the work gets pushed back and as it rotates it works itself even further out of the chuck.
Does the work get loose in the chuck and need periodic re-tightening?

See if a tail-stock centre support makes an immediate difference.
Long term, the bell-mouth can be corrected by grinding the jaws, but you need a way to "load" the jaws while doing it.

-brino

 

[Rob B]

Thank you Jim,Charles,Brino, for your advice. The work is held in a 3 jaw chuck. I well do further investigating on this issue now.

 

[wa5cab]

It could be any of the above. It could also be the following:

Loose gibs. They should be tightened to the point where it takes just a little force to rotate either of the cranks or turn the carriage traversing handwheel (depending upon which gib you are dealing with.
Loose tool holder (you don't say which type you are using.
Cutter not on center. Several people on eBay pedal a little plastic gadget with a self centering "V" on the front and a bubble on the top that are relatively cheap and work fine. Get one. Having the cutter on center is important.
Excessive DOC (depth of cut). You can take more while roughing in aluminum but don't expect not to have to take a spring pass or cut in order for the diameter to be what you expect.
Cutter is too light (small cross section) for the amount of cutter sticking out. Use (on a 10F) 3/8" or if your tool holder permits 1/2" square cutters. And keep the amount of cutter sticking out of the holder as short as practical.

 

[TommyD]

Getting a built up edge from the material adhereing to the cutter?

 

[Rob B]

Tommy D, thanks also for your response also. All u guys r so cool. I know u have my back. Checked some things today. Got the 10F at a swap meet, ( cheep ) with nothing extra. I bought a Atlas 5/16 tool holder. E bay. The material I'm turning (alu. alloy) has been beat on w/hammer. The problem is on the ends. Metal must b denser pushing my cutter away. Cross slide also backs off during the vibrations. Sound 1/2 right ??

 

[Rob B]

Tool also needs a tune up

 

[JimDawson]

The problem is on the ends. Metal must b denser pushing my cutter away. Cross slide also backs off during the vibrations. Sound 1/2 right ??

I think that is a pretty good analysis.