Tool With No Clearance

Jimsehr

Jimsehr

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Turning a ball with a tool that has no clearance at all.
I made a ball turner that takes a 1/4 round cutting tool on end and it will cut a ball as long as the tool is on dead center. If you go above center it will rub. And you can not face with it. To see it cut go to you tube and enter
ball turner
jimsehr
 
On a lathe, as long as the diameter is on the small side you can turn OD's without much clearance, some relief can however produce a better surface finish. You can't face without relief because the workpiece doesn't sweep down and away from the cutting edge - it's not tangential.

I made a ball turner with a 1/4" round tool bit also, with a hair of back and side relief just by angling the hand drill when I drilled and reamed the hole. And it wasn't accidental :p :)
 
Free machining 360 alloy brass, often used for tool demo's without coolant getting in the way, if you cannot get a nice finish and repeatable accuracy with that material you are doomed. It was designed for automatic screw machine products.
I realize that this is a Hobby Machinist forum, however making a video of turning a free machining material (I cannot stress how important the material is) may be a bit misleading. This is a video of a machine running parts in free machining brass that does not require coolant, one could not possibly do this dry in simple 1018 mild steel or 6061 aluminum.
 
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Wreck

This is a ball made out of steel with the same tool. So I guess it is possible. plus I have made lots of them out of aluminum.

IMG_0002-1-1.jpg

jimsehr
 
Never implied that it could not be done, merely pointing out the fact that doing it in 360 brass makes it look easy. Somewhere someone will build the same tool and try it on another material and wonder why it is not quite so easy. The attached video was to point out that in machine sales they always use this material because it machines so easily and may be run without coolant at high speeds and the chips are always broken. If made in gummy 304 for instance, that video would have been 10 minutes longer and be completely obscured by oil or coolant.
 
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Very cool application, Jim. Never thought to use a round tool bit in this way, and I liked the soundtrack on your video!
 
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