Beautiful spiral shaving drill machining - GIF

[Jon]

Beautiful spiral shaving drill machining.




Previously:

Perfect machining
Micro machining for watch parts - GIF
Machining a bangle - GIF
Bevel gear cutting - GIF
Cutting gear teeth GIF

[jimfols]

Waiting for the explanations. TIA

[Frank S]

12L14 will shave off like that

[hemmjo]

Waiting for the explanations. TIA

So many variables involved in making nice chips like that. Speed, feed rate, material, cutting clearances and angles, even temperature and how the material has "aged" after its production affect how the chips are formed. It is apparent that whoever made that set-up had them all correct.

[12L14]

12L14 will shave off like that

Well - if You say so

[Frank S]

Well - if You say so

Ha,ha I forgot about your screen mane LOL

[Jon]

[Frank S]

<video controls autoplay loop>
<source src="https://s3-us-west-1.amazonaws.com/hmt-forum/spiral_polished_lathe_turnings.mp4" type="video/mp4">
Your browser does not support the video tag.
</video>

And the hotter the tool and the part become the longer the curls will be

[hemmjo]

When was in college back in the early 70's, the manufacturing engineering department had a special lathe set up to test all kind of cutting tools. They were doing research on ceramics. It had massive ways, and head and tail stocks. It was coupled directly to a massive electric motor, something like 50 HP at 3600 rpm. I am thinking surface speed was something insane, like 7500 FPM for the piece on this day.

When I saw a demonstration, mounted in the machine was a hunk of steel that had to be about 8" dia, and 4 feet long. It was driven and supported at the head stock by 4 hardened pins in matching holes drilled in the "chuck" and work piece. On the tail stock end was a large bearing, supporting that end and pressing it against the headstock.

I do not recall the exact feed rate and depth of cut. Perhaps 0.030 feed and 0.250 or more depth of cut. When it was turned on it took a couple of seconds to get up to speed, like it may have had a VFD drive system. When the guy, the professor had his assistant do it, engaged the feed lever, the motor changed tone just a bit when the cutter hit the work piece. The silver chips flew in a nice arc, turning purple at about the apex then landing in the chip tray. The whole 4 foot long cut was over in a manner of seconds. You could feel the heat radiating from the chip pile from way back, but the work piece was not even warm to touch. The surface was like a mirror. I was totally amazed.

I wish I had a video of the monster.

[Ralphxyz]

re: "hotter the tool and the part become the longer the curls will be"

That interesting, thanks Frank! Actually you can see by the end of the video that the curls are much longer and blue.

Ralph