Bit suggestion

[Tony Z]

For routing a dado across a sheet of plywood, what type of bit is recommended? I'm planning on using a guide bushing and the dado is to end up 3/4" wide by 3/8" deep.

Thanks!

[MichaelMouse]

I like my spiral carbide.  In this case 1/2 should provide preventive overlap.

[Tony Z]

Would that be an upcut style bit or straight?

[Steve N]

When routing completely across a piece of ply I always use this type of jig, and just a straight cut bit The jigs bumper strips keep you from needing any kind of bushing on the bit. The plus is no matter what size stock you plan to insert into the dado, it's a friction fit.

[JGrout]

Would that be an upcut style bit or straight?

I would use a down cut spiral on plywood if you use a bushing 

upcut and straight with a bushing will lift the adjacent fibers and leave  more work to finish.

[Tony Z]

Thanks to all for the guidance. I like the jig Steve, as well as the bit info!

[kurt18947]

Thanks to all for the guidance.  I like the jig Steve, as well as the bit info!

I made a similar jig to that but use a top bearing router bit with it. Works very well, especially with 'odd' sized sheet goods. The only downside for me is that I can't make dados narrower than 1/2", the size of the smallest top bearing pattern bit I'm aware of. Mark Spagnuolo made a similar jig but used a bushing instead of a bearing guided bit. His jig would make narrower dados but I don't recall the details.

[Steve N]

The one I linked to it has 2 strips of wood/ply/hardboard on the outer edges of the jig for the edge of the router itself to run along. Don't get me wrong I love a bearing guided bit, but for these dado jigs they make any straight cutting bit work like magic. Actually you need a bit smaller than you dado is to be, and you make the cut in 2 passes, but it will result in a zip, zip, perfect fit


Spaghno's jig is for a 5/8" guide bushing, and a 1/2" router bit. His jig is awesome for 3/4" stock, not so much for less.



Below Glen Huey walks you through a very simple edge guide bit, where you can use smaller diameter bits, and guide bushings, nothing is predetermined, and the jig is 3 pieces. I will say however that to work, you have to have that stop block going across the top of the jig DEAD NUTZ on, or all your dado's will be off by however much you are off square.




If you want dado's that are perfectly spaced without serious measuring this is your Huckleberry.





Oooops what is this about only 3 videos? I'll be back Ahhhhnold said.....


The jig I initially suggested, The WoodSmith jig will do any of the above, and I haven't seen one that is neither bit, or bearing dependent, and it's easy to make, and piece of cake to use.

[Steve N]

Told ya


Bob Lang's take on a dado router jig below.

[Tony Z]

Thanks Steve!