# Lathe Boring VS Horizontal Mill Boring



## DBC (Jun 3, 2006)

Okay, besides the machine, what is the real difference between Boring on a Lathe and Boring on a Horizontal Mill?


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## cmacclel (Jun 3, 2006)

DBC said:


> Okay, besides the machine, what is the real difference between Boring on a Lathe and Boring on a Horizontal Mill?




The difference? Maybe should elaborate more on your question.


Yes you can bore on both machines but you limited to depth on the mill where as the lathe has 12" boring bars.

Plus you need a boring head for the mill which is 10x the cost of a regular boring bar for the lathe.

Mac


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## McGizmo (Jun 3, 2006)

On a mill, the part is moved along a tool path and the cutting tool is rotating. On a lathe, the tool is moved on a tool path while the part is rotating. 

In the case of say a simple straight bore, on a mill, the rotating boring bar is advanced into the stationary part. On a lathe, the part is rotating in the chuck and the boring bar is advanced into the turning part.

Concentric inside and outside surfaces are much easier to accomplish on a lathe as these all share the same (Z) axis about which the part is rotating.

A mill is not limited to concentric surfaces but it also requires considerable set up in tooling and typically a rotary index if you want to machine multiple surfaces which all are concentric and share the same major axis. With CNC, the issue is simplified as well as more complex.

I probably didn't answer your question but it is a simplified question that may or may not have a simple answer; beyond the main difference between a mill and lathe. That difference is the fact that a lathe rotates the part and a mill rotates the cutting tool.


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## DBC (Jun 3, 2006)

Thanks! 

I believe that you can get a larger peice done on a Mill compared to boring on a Lathe but I am not sure about that. 

By the way, also, if I wanted to use a reaming method to enlarge a hole, are there any disadvantages to reaming that I should know about? 
Thanks again, in the absence of a Mentor you guys are a lot of help with this!


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## gadget_lover (Jun 3, 2006)

There are some seriously big lathes, and some very big mills too. There are pictures online of lathes with 30 foot long beds turning metal that weighs many tons. With a really big mill you can use really big boring bars too.

I don't think you use a normal horizontal mill for boring. The horizontal mill has a working shaft which extends across the table. The cutting tool tends to look like a serrated wheel on a shaft. A vertical mill has a head suspended above the table with the chuck ( or tool holder) pointing down towards the table. 

There are horizontal boring machines that are designed to bore from the side. They have the motor and tool holder mounted to the side of the table. 


As for the rest of it.... The previous posts did a great job of explaining.

Daniel


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## TENMMIKE (Jun 3, 2006)

i use a horizontal mill for boreing all the time , i use KOMET bore heads that are 13 inches long to bore boeing 737 flap beams several times a month, i can hold about .0002. .0004 (temp variations) ill post some pics tommarow after i get off work


gadget_lover said:


> There are some seriously big lathes, and some very big mills too. There are pictures online of lathes with 30 foot long beds turning metal that weighs many tons. With a really big mill you can use really big boring bars too.
> 
> I don't think you use a normal horizontal mill for boring. The horizontal mill has a working shaft which extends across the table. The cutting tool tends to look like a serrated wheel on a shaft. A vertical mill has a head suspended above the table with the chuck ( or tool holder) pointing down towards the table.
> 
> ...


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## gadget_lover (Jun 3, 2006)

Hey, Tenmike, I'd like to see those pictures. It sounds like you use some seriously neat machines.

All the home/small shop horizontal mill pictures I've seen have had the shaft supported at both ends with a cylindrical tool. I was thinking in terms of home shop machines. I don't see any reason why you can't have the tool supported at only one end as in a vertical mill.

Daniel


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## tvodrd (Jun 3, 2006)

Me too, and what gadget_lover said farther above. A traditional horozontal mill is only 3-axis and IMO incapable of boring without some creativity. I ran an olde one once in a collage machine shop class and used it to make some additional KDK-copy tool holder blocks, less the dovetails. From what little I know,  horiz. mills fall in the same category as _shapers._ :green:

Larry


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## PEU (Jun 4, 2006)

The other day I saw an Okuma vertical machining center that looked like a lathe but it had so many movements it can machine a turbine blade, something like this http://www.steintek-download.de/ms3/turbineblade/blade.jpg without taking the piece of the chuck/holder.

It was pretty amazing.


Pablo


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## wasabe64 (Jun 4, 2006)

I always believed the shape of the workpiece and the angle of the bore in relation to the centreline dictated appropriate machine. There is overlap of course...


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## TENMMIKE (Jun 6, 2006)

sorry guys , i forgot , , ol lady has it now i might see her in 2 days as shes out of town , i might can use camera at work, will see, no matter what ill post with pics soon , , and how the boreing ops are done. btw the horizontal im talking about is a 4 axis( has a rotery table) (this is a CNC machine)


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