# Wood Thickness



## jbert (Feb 20, 2010)

I need some help here. I bought a 1/2" roundover bit and then used it on some 3/4" thick practice board. The roundover was great but it would not go all the way to the back side. Did I need a 3/4" roundover?

Does the material thickness designate the bit to use?


Thanks


JIM


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## jbert (Feb 20, 2010)

*More on question*

I should have said. If I want the roundover to start at the back top then the bit should equal the wood thickness?



JIM


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## jschaben (Jun 21, 2009)

jbert said:


> I should have said. If I want the roundover to start at the back top then the bit should equal the wood thickness?
> 
> 
> 
> JIM


Hi Jim - That's correct. Roundover bits are spec'd to the _RADIUS_ of a circle it could produce. ie. a 1/2" roundover would make a 1" diameter circle or in effect a 1" dowel. Therefore, on a piece of 3/4" stock, you would end up with about a quarter inch untouched on the top surface.
Hope this helps


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## jlord (Nov 16, 2009)

A 3/8" roundover will give a full bullnose on 3/4" stock. Route from top & bottom. I would do this in a table so you have the fence to guide your material for the second side. Route half of your stock (will route 3/8" - half of 3/4"). flip piece over the route other side (the 3/8" remaining) & your two passes will meet & give a full bullnose on your 3/4" material.


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## jbert (Feb 20, 2010)

John / James --- thanks ---- guess I can increase my bit inventory.


Jim


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## jlord (Nov 16, 2009)

If you want a round over to go from the top edge to the side bottom edge you will need a 3/4" roundover bit. I would still do this with a router table as it does not leave a flat edge for a bearing to follow.


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## tdublyou (Jan 8, 2010)

jbert said:


> John / James --- thanks ---- guess I can increase my bit inventory.
> 
> 
> Jim


Jim,
If you're going to buy a new bit, you might want to look at a bullnose bit. It will do what you want in one pass though it is a bit more specialized and therefore not as utilitarian as a roundover. Guess it depends on how often you will need to perform that operation.

Tim


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