# Spiral Bit Question



## cabinetman (Apr 23, 2007)

The question I have concerns types of spiral bits. I know there are upcut, and downcut bits. I ran across what's called "*left hand spiral bits*"...in *upcut* and *downcut* profiles.

*On this page*, you'll see the choices. What's a left hand bit?


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## gregW (Mar 14, 2007)

cabinetman said:


> The question I have concerns types of spiral bits. I know there are upcut, and downcut bits. I ran across what's called "*left hand spiral bits*"...in *upcut* and *downcut* profiles.
> 
> *On this page*, you'll see the choices. What's a left hand bit?


A left hand bit is for use in a counter-rotating spindle.


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## cabinetman (Apr 23, 2007)

gregW said:


> A left hand bit is for use in a counter-rotating spindle.



Thanks for the quick response. So, for "counter-rotating spindle", are you referring to a shaper? I'm not familiar with any reversing routers...if there is such a thing.


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## bobj3 (Jan 17, 2006)

Hi must be, we had a member who had a router that was made to turn backwards and wanted to know how to rewire it so he could use it the right way..but it's not a big deal ,just need to feed from the left side if it's in a router table..

But I also think it's play with term,left hand..

http://www.holbren.com/spiral-downcut-left-hand/
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cabinetman said:


> Thanks for the quick response. So, for "counter-rotating spindle", are you referring to a shaper? I'm not familiar with any reversing routers...if there is such a thing.


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## gregW (Mar 14, 2007)

cabinetman said:


> Thanks for the quick response. So, for "counter-rotating spindle", are you referring to a shaper? I'm not familiar with any reversing routers...if there is such a thing.


They are probably more commonly used in a multi-head CNC machine where the counter rotating spindle would compensate for feed direction. 

it gets a bit confusing but Downcut / Upcut refers to the direction of the helix...a “downcut” bit has a left hand spiral helix and an “upcut” bit has a right hand spiral helix.

Standard router bits are right-hand cutting bits in reference to the orientation of the cutting edges. So a standard “downcut” spiral bit would be considered a right hand cut / left hand spiral helix bit…clear as mud, right? 

If you look at the cutting edges in the picture that you linked to of the Whiteside Left hand spiral bits you can see that the cutting edges are oriented to work in a counter-clockwise rotation. 


I don’t know of any conventional router motors that spin counter-clockwise...


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## Gene Howe (Jul 10, 2007)

So very confusing. :blink:

Just when I finally figured out which end of the spiral bit goes in the collet, now I gotta deal with lef handed bits as well.:wacko:


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## CanuckGal (Nov 26, 2008)

> So very confusing.
> Just when I finally figured out which end of the spiral bit goes in the collet, now I gotta deal with lef handed bits as well.


Yep it's always something.


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## gregW (Mar 14, 2007)

Gene Howe said:


> So very confusing. :blink:
> 
> Just when I finally figured out which end of the spiral bit goes in the collet, now I gotta deal with lef handed bits as well.:wacko:


dealing with the left handed cutting bits is easy...if you ever get one all you need to remember is that it won't work in your router so you need to exchange it for one that will


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## Hamlin (Dec 25, 2005)

Next they'll be selling "left handed screwdrivers".


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## CanuckGal (Nov 26, 2008)

It's those left handed metric adjustable wrenches I have trouble with.


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## MikeMa (Jul 27, 2006)

I am still looking for those left handed pair of pliers I get sent looking for....


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## BigJimAK (Mar 13, 2009)

Gene Howe said:


> So very confusing. :blink:
> 
> Just when I finally figured out which end of the spiral bit goes in the collet, now I gotta deal with lef handed bits as well.:wacko:


Don't things spiral backwards down under.. like water in the drain???


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## jw2170 (Jan 24, 2008)

BigJimAK said:


> Don't things spiral backwards down under.. like water in the drain???


So that where my order went.....


:jester:


James


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