# What size router bit do I need?



## Microscopes (Jan 3, 2016)

Sorry for what is probably a stupid question to the professionals on here.

But I am trimming a 3/4 piece of cabinet grade plywood with a router and I am purchasing a round over bit.

1) Do you purchase a 3/4" radius bit for a 3/4" piece of wood? I'm thinking a 3/4" bit would router the entire edge of a 3/4" plywood right?

2) Borrowing my fathers Ryobi R-150. Quite old. I keep reading about "shank" sizes. But I cant figure out what size bit this R-150 takes. Can anyone help me?

Thanks.


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## shoot summ (Feb 21, 2014)

Microscopes said:


> Sorry for what is probably a stupid question to the professionals on here.
> 
> But I am trimming a 3/4 piece of cabinet grade plywood with a router and I am purchasing a round over bit.
> 
> ...


The radius has more to do with appearance, than the thickness of the stock.

I've done everything from 1/16" to 3/4" on 3/4" stock.

Are you sure you want to round over the edge of ply? Might not look so great.


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## Microscopes (Jan 3, 2016)

shoot summ said:


> The radius has more to do with appearance, than the thickness of the stock.
> 
> I've done everything from 1/16" to 3/4" on 3/4" stock.
> 
> Are you sure you want to round over the edge of ply? Might not look so great.


It's not really about look to be honest.

It's a bench, and the square edge kinda hurts to sit on.


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## NickB (Sep 24, 2013)

A 3/4" roundover will round the edge completely. 

Using the router in the conventional way, like this guy:








... won't work because you won't have any material for the bearing to ride on. So, you'll have to turn the router on edge (scary), use a table with a fence, or clamp on a straightedge.

Most of us don't do complete roundovers (waterfall) often. They're generally not the most attractive edge, particularly on plywood. If you wanted a full bull nose (like a D shape), you have the same problem with not having a bearing surface whether using a 3/8" roundover or an actual bullnose bit.

If you're just looking for an "eased" edge, I'd just use a 1/8" to 1/4" roundover bit on both top and bottom. 

As far as shank size, it depends on the collet in your router. It will be either 1/4" or 1/2" and could have been changed at some point, so you'll have to check it. Probably 1/4".


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## Microscopes (Jan 3, 2016)

NickDIY said:


> A 3/4" roundover will round the edge completely.
> 
> Using the router in the conventional way, like this guy:
> 
> ...


Extremely informative.

Thank you so so so much!


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