# plywood dado



## Salem (Apr 13, 2011)

Can I use a router to cut Dado on plywood sheet


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## walowan (Jan 21, 2011)

Of course you can, the sharper the bit the better the cut. You might try a down spiral bit to reduce tear-out.


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## jlord (Nov 16, 2009)

Hi Salem, Welcome.
If you are going to fit ply into your dado, they make bits that are undersize for a better fit. 3/4" ply is not always 3/4". Its usually undersize. Same for the other sizes of ply. If it's MDF that usually is ok unless it is MDF light which is thinner like ply.
Undersized Plywood Router Bit Set - Rockler Woodworking Tools


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## bobj3 (Jan 17, 2006)

Hi

Compression Up/Down Spiral Router Bit

This 2 flute solid carbide bit is needed to get clean, chip-free and splinter-free cuts in composite sheet goods such as Melamine or 2-sided Formica/Laminates and veneered plywood. 
The Up-shear/Down-shear design of the bit cuts toward the center of the sheet from both sides at once, saving time and eliminating waste.

MLCS solid carbide router bits

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## jw2170 (Jan 24, 2008)

G’day Salem

Welcome to the router forum. 

Thank you for joining us


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## Salem (Apr 13, 2011)

Thank you for the answer, I was told never rout plywood
I am in fact planning to use 19 ply plywood inported from russia by Langevin et Forest, as the layers are very thin I am expecting this wood to behave like a solid wood but you never know, I will try finger joint but most likely will revert back to Dado if I experience tearout.
Thank you
Salem


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## Salem (Apr 13, 2011)

thank you, this forum looks very interesting, I am already finding lots of answers to my questions


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## Salem (Apr 13, 2011)

Thanks Jame I am in fact planing to use an undersized bit and cut 2 times, I have an other question is a plywood bit would make a cleaner cut?
Thank you
Salem


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## Cherryville Chuck (Sep 28, 2010)

Salem,
James posted a link to a video recently showing how to make a router guide for cutting grooves. Maybe if he sees this he will repost it. It is a thick piece of mdf or plywood which acts a fence glued to a thin piece of plywood which is wide enough that you have to cut a bit off when you make your first router pass. This shows where your bit will cut. (You have to keep using the same bit every time of course). All you have to do that way is to put a piece of your plywood edge down on the piece you want to rout and pencil mark it. Place the guide on one line and cut then put the guide on the other line and cut that side. Doesn't matter what your plywood thickness is, you will always use the same bit. When you make the guide use a factory edge for the side the router will butt against. The other side doesn't matter.


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## GarethHarvey (Apr 2, 2011)

I done a lot of this recently, our 3/4 ply in the uk is actually 18mm, I bought a 18mm bit and it done the job with excellent results


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## bobj3 (Jan 17, 2006)

4 pc 1/2" SH Dado Plywood Straight Router Bit Set | eBay



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## istracpsboss (Sep 14, 2008)

We are back to the metric thing here. Since most plywood on the market worldwide is produced on metric machinery and is a metric thickness, why isn't it properly described in markets like the US? Don't your consumer protection laws cover misselling 18mm plywood as 3/4" etc. ? If it was properly described in the first place, buyers would know to buy the correct matching bits.
Elsewhere, it is always sold by its actual, metric, thickness and buyers have no trouble using 10mm, 12mm, 16mm or 18mm bits.
Cheers

Peter


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## tdublyou (Jan 8, 2010)

istracpsboss said:


> We are back to the metric thing here. Since most plywood on the market worldwide is produced on metric machinery and is a metric thickness, why isn't it properly described in markets like the US? Don't your consumer protection laws cover misselling 18mm plywood as 3/4" etc. ? If it was properly described in the first place, buyers would know to buy the correct matching bits.
> Elsewhere, it is always sold by its actual, metric, thickness and buyers have no trouble using 10mm, 12mm, 16mm or 18mm bits.
> Cheers
> 
> Peter


Peter,
No disrespect intended here but if we do that we will no longer be able to sell 2 x 4, 2 x 6, et al.
As with dimensional lumber the plywood is sold as nominal size.


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## Ralph Barker (Dec 15, 2008)

istracpsboss said:


> We are back to the metric thing here. Since most plywood on the market worldwide is produced on metric machinery and is a metric thickness, why isn't it properly described in markets like the US? Don't your consumer protection laws cover misselling 18mm plywood as 3/4" etc. ? If it was properly described in the first place, buyers would know to buy the correct matching bits.
> Elsewhere, it is always sold by its actual, metric, thickness and buyers have no trouble using 10mm, 12mm, 16mm or 18mm bits.
> Cheers
> 
> Peter


It's just that we're accustomed to describing various things as being larger than they really are, Peter.


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## istracpsboss (Sep 14, 2008)

I thought that was only in Texas ?

Cheers

Peter


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## istracpsboss (Sep 14, 2008)

tdublyou said:


> Peter,
> No disrespect intended here but if we do that we will no longer be able to sell 2 x 4, 2 x 6, et al.
> As with dimensional lumber the plywood is sold as nominal size.


I can understand that with lumber, which is less dimensionally stable and may have shrunk since being measured, so they need to cover themselves, but plywood and MDF are fairly consistent. Incidentally, even though the thickness is metric, sheet sizes still seem to be imperial, even here. The odd sounding metric sheet dimensions convert to 8 x 4.

Cheers

Peter


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## Ralph Barker (Dec 15, 2008)

istracpsboss said:


> I can understand that with lumber, which is less dimensionally stable and may have shrunk since being measured, so they need to cover themselves, but plywood and MDF are fairly consistent. Incidentally, even though the thickness is metric, sheet sizes still seem to be imperial, even here. The odd sounding metric sheet dimensions convert to 8 x 4.
> 
> Cheers
> 
> Peter


Strangely, most of the Baltic Birch plywood that gets imported here comes in 60"x60" sheets, even though it's also made in 4'x8' sheets (or, so I hear). The rationale behind the 60"x60" dimensions eludes me, while the 4'x8' size obviously relates to U.S. building standards (studs on 16" centers, etc.).


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