What is a mill?

[bkboggy]

I'm very new and so I have lots of questions that for some of you guys might seem like... DUH! But, better ask than not know.

Lathes are those things that make objects spin and you can cut shape out on any side of them, correct?

What is a mill, though?


Would a CNC router cutting wood be considered a mill?



-BK

[irving2008]

Originally Posted by bkboggy I'm very new and so I have lots of questions that for some of you guys might seem like... DUH! But, better ask than not know. Lathes are those things that make objects spin and you can cut shape out on any side of them, correct? What is a mill, though? Would a CNC router cutting wood be considered a mill? -BK

Milling is a process whereby a rotating cutter passes along/through/over the workpiece.

In a vertical mill the cutter axis is vertical and the cutting action takes place on the end or side of the cutter. In a horizontal mill the cutter rotates in the horizontal plane and the cutting action is on the circumference or face of the cutter.

The other key aspect of a mill is that the workpiece can be moved and accurately positioned in three dimensions relative to the cutter.

Therefore a CNC router IS a (limited) form of vertical mill.

Here is a useful description of various cutting processes...

[bkboggy]

Thank you for the information. That link is very useful.


-BK

[tausugAir]

Irving2008 .. Thanks for that link, its graphical... One further quetion, how is it different an ordinary turning to gear/thread cutting on a lathe when both tooil move along the axis of the piece that is worked on? Appreciate your clarifidation to a newbie....Regards

[irving2008]

Originally Posted by tausugAir Irving2008 .. Thanks for that link, its graphical... One further quetion, how is it different an ordinary turning to gear/thread cutting on a lathe when both tooil move along the axis of the piece that is worked on? Appreciate your clarifidation to a newbie....Regards

Not sure I fully understand your question, but if I do you are asking the differecne between plain turning and thread cutting (gear cutting is something different again).

Basically there is no difference as you point out, both processes traverse the cutting tool along the rotational axis of the workpiece. The difference is how that traverse is achieved and its speed.

When plain turning the speed of traverse is dictated mainly by the finish required and the depth of cut etc and is chosen by the operator (whether manual or power feed).

When thread cutting the leadscrew that moves the tool is solidly linked to the spindle that turns the
workpiece by gears such that the tool moves a precise amount horizontally for each revolution of the workpiece. Thread cutting is therefore done (usually) at a much lower speed therefore the lathe usually has additional 'backgears' to slow the spindle down further. Modern lathes encompass all of the gearing in a single gearbox but older ones have backgears and manually changeable gear wheels. Since the thread cannot be cut in a single pass the other important ability is to register the starting point of the cut so that multiple passes can be cut identically. This involves a mechanism on the leadscrew called a thread chasing dial.


For newbies everywhere I recommend watching the MIT Machine shop videos, videos 1-3 are basic machine shop work, video 4-7 cover milling machines and 8-10 cover lathes (video 9 covers thread cutting towards the end)

[tausugAir]

Irving2008 ..

Thanks for the clarification.. Now, I understand... Thanks, too, for the link just been there and it's educational.. Regards...

[tausugAir]

Thanks for the differentiation, Machinepier. . great info for a newbie!

[Radical!]

I'm new here as well and just wanted to thank "irving2008" for the MIT video tutorials link. Its a great help in the field and as a reference also. Once again thank you. Perhaps we could have a moderator sticky the link for the new guys that are welcome to this great site.

http://techtv.mit.edu/tags/336-prototype/videos

[bkboggy]

I agree, that's good stuff. Not only do they teach ways of machining and plotting on parts, but they also describe a huge amount of tools. I didn't know the existence of some of them until I saw these videos. I actually own some of them right now just because of those videos--made my life easier, that's for sure. Definitely sticky them--A MUST. Not sure which forum would be more appropriate though... metalworking? Honestly, you can apply the knowledge learned in those videos in a lot of areas.