# ROUTER BIT FOR METAL



## John J (Dec 29, 2007)

Say I had a three inch cube of steel. Say I wanted to Make a squar depression in it. 

Is there a metal bit that acts like a wood router bit? 

I figure I would need a mill to run it.

What do you call such a bit?


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## Gary Armitstead (Jan 2, 2008)

JJ,

End mill or a ball cutter. The end mill is flat bottom. The ball cutter has a full radius on the bottom. Spiral flutes for both-no straight flutes.


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## Semper Vaporo (Jan 2, 2008)

Posted By John J on 11/01/2008 5:30 PM
Say I had a three inch cube of steel. Say I wanted to Make a squar depression in it. 

Is there a metal bit that acts like a wood router bit? 

I figure I would need a mill to run it.

What do you call such a bit? 



Well, you ain't never gonna drill a "square" hole in metal... not like a mortising drill with the square chisel for wood.

But if rounded corners are acceptable you make the hole with an "end mill". Oh dear, now if I can remember the name of the type of bit that will drill... it has 4 flutes and cutting edges on the "end", two of which meet in the middle so that it removes metal there (a two flute bit often does not meet in the middle of the end and actually will drill a bit of a circle before the center contacts the original surface and "drilling" stops. You can also drill a hole big enough for a 2 flute mill to fit in and then move it sideways (or the material sideways) to eat out the rest of the "hole".

You move the bit around, all over the area to be the hole and it eats out the material, but since the bit is round, the corners are rounded too. The smaller the bit the smaller the radius of the corners, but the slower it removes the material (the more passes you have to make to eat it all).

It "could" be done on a lathe (bit in the chuck and the part in the tool holder... depends on how big a hole you need.

Could also be done in a drill press if you have a method of holding the part firmly while moving it around, but this is terribly hard on the spindle of the drill press as it is not designed for sideways pressure.

You could also kind of get there by drilling multiple overlapping holes, but that requires a very stiff drill bit so it doesn't flex to the side and miss drilling close enough together to get all the material removed for the full depth. It also leaves the bottom of the hole rather rough.


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## John J (Dec 29, 2007)

Thanks for the Input. 

The conrners do not have to be squar. I figured thay would be round to matcht the bit. 

This is all steming from my Posts on the Mills and Lathes, plus the CNC plasma cutter.

RPM for this bit must be high/

What about using a firmly mounted "ROTO ZIP" 

Also a X and Y milling table.


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## Allegheny (Jan 2, 2008)

There are two simple ways to "drill" a square hole in metal. 

The first, and easier method, is to use a broach of the appropriate shape and size. This will only work for through holes, however. 

There is also a very specialized bit/holder/guide set that can drill blind or through holes of virtually any shape (triangular, square, pentagonal, etc) with sharp corners. The name of the company escapes me at the moment, but I believe they are located near Pittsburgh. Such tooling is NOT cheap. If any really needs to know where to find these tooling sets, I'm sure I can dig up the info. 

Brian


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## Havoc (Jan 2, 2008)

You will need a mill for it, a wood router has too high rpm to use a metal mill bit and not enough stiffness.


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## Trains West (Oct 4, 2008)

I agree ....... most metal bits are run in the hundreds of rpms not the thousands........


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## Gary Armitstead (Jan 2, 2008)

Actually the new high speed machining done in NC mills, are incredibly fast. 25,000 rpm and up at feedrates nearing 200 to 500 inches per minute or more in STEEL, not aluminum. AL is even faster!


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## ralphbrades (Jan 3, 2008)

JJ, this may sound a it strange -but have you every heard of a device called an "EDM" or Electric Discharge Machine? This could be what you are looking for. 

viz: http://en.wikipedia.org/wiki/Electrical_discharge_machining 

There are also a few books on making your own -here is one from my favourite UK book seller... 

http://www.camdenmin.co.uk/build-an-edm-p-2260.html?p=product 

regards 

ralph


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## Gary Armitstead (Jan 2, 2008)

I started using EDM machines in the very early sixties when I first started in the die sinking trade. I always used carbon electrodes, sometimes copper. You can do very small, intricate shapes that are virtually impossible with milling machines.


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## Havoc (Jan 2, 2008)

I not only heard about high speed metal milling, I had pieces made that way and saw the mill in action. It is a great tool but it isn't a wood router... Same for the EDM and wire cutter. Beautifull machines for some type of work. When we had moulds made for plastic injection, those were the tools used to make the cavities.


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## Trains West (Oct 4, 2008)

to do high speed milling you have to have a very rigid machine with a good system for cooling the bit or you will just burn the material you are milling to the bit or break it ........

a cnc machine like a HASS is not a router.........

home milling is best done a slower speeds ...........


if you are going to try at faster speed the you shoud use a single flute end mill ........

also for some routers you can slow them down with a motor controler .....


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## Rods UP 9000 (Jan 7, 2008)

JJ 
What do you need milled??? Send it to me. 
Rodney


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## John J (Dec 29, 2007)

Posted By Rods UP 9000 on 11/03/2008 2:05 PM
JJ 
What do you need milled??? Send it to me. 
Rodney

Thanks for the offer Rodney. But I am planning a shop. I think


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