Beautiful spiral shaving drill machining - GIF

Beautiful spiral shaving drill machining.

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Previously:

https://www.homemadetools.net/forum/...605#post132626
https://www.homemadetools.net/forum/...929#post133702
https://www.homemadetools.net/forum/...582#post132516
https://www.homemadetools.net/forum/...850#post108698
https://www.homemadetools.net/forum/...8594#post87797

Waiting for the explanations. TIA

12L14 will shave off like that

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Originally Posted by jimfols

Waiting for the explanations. TIA

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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.

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Originally Posted by Frank S

12L14 will shave off like that

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Well - if You say so ;)

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Originally Posted by 12L14

Well - if You say so ;)

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Ha,ha I forgot about your screen mane LOL

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Originally Posted by Jon

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

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.

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

I do not think you can make a blanket statement that chips are longer as things heat up. Chip creation is dependent on too many variables to say that.

Actually, this video does not start at the beginning, so there were lots of chips made before the clip started. By my count, there were about 3 small chips made between 0 and 3 sec, 3 chips between 3 and 12 seconds, then 3 more between 12 and 15 when the clip ended. The long ones blued up while still attached, but the first 3-4 spirals are still base color. You can bet that the little once blued also after they fell into the chip tray.

Under ideal conditions, all of the chips created would be the same. The difference in chips can be caused by many factors, most common among them are; lack or machine or tooling stiffness, incorrect tool geometry, imperfections in the material being machined, built up edge on the cutting tool forming then breaking away.

When you look closely at the finished surface, you can see variations, most likely caused by one of the factors above. From this evidence I would say this is a good set-up, perhaps very adequate for whatever is being done, but it is not yet OPTIMAL!!!!

This video regarding BUE (Built Up Edge) has always fascinated me. https://www.youtube.com/watch?v=mRuSYQ5Npek

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Originally Posted by Jon

Beautiful spiral shaving drill machining.

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Post 1, appears to be 356 cast aluminum.

hemmjo's ISCAR video is spectacular; watching a good set-up is one thing, that a user could examine directly after; it would take longer than what video proves.