I'm going to be starting the casework for my kitchen island soon and I have a few pieces that are going to be a bit long and awkward to try and get a good cut on the tablesaw with a dado set. Going with the theory that it's easier to bring the tool to the wood in this case, my 1010 seems to be up for the challenge . I did a couple of test cuts using a standard 3/4" straight bit and the fit's not horrible but I'd like to get it a little tighter if possible.

Freud, Whiteside, and a few others make slightly undersized bits for routing plywood so you get a tight fit in dados and grooves but I haven't used any of them yet. Really doubting I'll find any with a 8mm shank but 1/4" shank with the straight 3/4" bit seems to work fine (only going 1/4" deep for the dados) so I'm guessing any good name brand 1/4" shank bit is going to work out OK.

Anyone using their 1010 for plywood dados? Any favorite bits to use for this?
Any help is appreciated...
Thanks
-Jim

You could also go with a 1/2" (or anything less than the plywood thickness)  straight bit and sneak up on an exact fit.

Seth

Paul Marcel did a video showing how to make exact fit dados with several tools including a router+rail and the Bridge City Kerf Maker.

http://www.halfinchshy.com/2011/06/bridge-city-km-1-kerfmaker-users-guide.html

The router bit is about 2/3 the way into the video.

Actually, the Festool OF1010 router uses and is supplied with both 1/4" and 8mm collets.

I like the Freud downshear mortising bits, they give a pretty clean cut on both sides and they're available in 1/32 undersizes for ply.

For the absolute ultimate in fitment you'll need to make yourself a jig: Cut two straight rips of the material you're using, long enough to span your workpiece plus a a few inches for a couple of spacers and whatever you want to use for a fence. Add a fudge factor for trimming. They should be half as wide as the OF1010's base or more, if you're routing 24" case sides I'd suggest 4" or wider for strength. Make two short crosscuts from your shelf material, slightly shorter than its thickness.  Turn them 90 degrees and use them as spacers to glue the two rips together, don't clamp them real tight(you might want to add a piece of brown paper bag as a shim so you can get the shelf in). Now crosscut one end of the assembly dead-nuts square and add a fence.

 Clamp the jig across the work and use any top-bearing flush trim bit smaller than the thickness of your shelf and short enough to allow for the depth of the dado and the thickness of your jig. Rout out out your shelf dado up one side and down the other and avoid climb-cutting.  Just make sure you're routing in the right direction. If you want to be picky get yourself a 1/4" shank downshear bit and a bearing to match. Now you're officially splitting red cat hairs....   Just don't forget the brown paper bag or you'll never get the thing together....

It's a matter of paying your money(or time) and taking your choice. For me, the 1/32 undersize bits are close enough as long as I'm consistent in assembly. YMMV.

HTH,
Bill

As stated above the OF1010 is supplied with a 1/4 inch collet. Freud makes under sized plywood bits in the 1/4 inch collet sizes. These are nice bits and will make a snug fitting dado.

I agree with andvari. 

Using the KM-1, as shown in Paul's video, allows the thickness of the plywood to be all over the place, and it might very well be, even from the lot, and you still can get a perfect fit every time.

Brice,

I'm a pinhead so no offense taken.    

BTW, Joe was from Staten Island, NY

The best way to make a dado/groove for plywood is by running two passes.  I think the key is that plywood is 'nominal' 3/4", which is a bit of the industry word to mean "take what you get; we don't check it".

I have a set of plywood bits, but not because I expected to use them for a one-pass groove that would fit well.  Since I use two passes, it doesn't matter the size of the cutter as long as it is larger than half the size of the groove I want.  I got the plywood set on a clearance for next to nothing; they work well (not as well as a nice spiral, but I didn't get 4 spirals for $9).  As Andvari and GreenGA mentioned, I use the KM-1 to exactly size the groove.  There are other ways to do it, but that one is fast and usable on a number of tools (dado stack comes to mind).

Speaking of spiral bits, a compression spiral will give you very clean and fast grooves.  That's all I use when grooving plywood unless it is really shallow in which case I use a down-spiral.

Don't waste your money on fancy bits that will never fit sheet to sheet.  John Lucas's tip works flawlessly.



Sent from my DROIDX using Tapatalk

Yeah, I know you're a pinhead, but I forgot Joe was from Staten Island.

Since I began using eCabinets about 4yrs. ago, I've been using BLIND DADO joinery on everything that comes off the CNC,  and since I started using FESTOOL, I now use BLIND DADO on everything else that doesn't come off the CNC... 
 
I should add, that I tried on a couple prior occasions, and determined the joints were too time consuming to machine manually, but with Festool, that's no longer the case.
Blind Dado joints have a bit of a learning curve to them,  but once you find your "best way" to machine them,  they go pretty fast.



By the way, the only "Plywood Bits" I use are from Collins,  and they are not for dados,  rather for edge joining plywood.  http://www.collinstool.com/base.php?page=collins_ply_prep.htm
for conventional dados, the 2 pass sneek-up works best.

There are a number of jig videos on YouTube that show how to make a jig, using scrap, to get perfect dado's every time, no matter the thickness of the inserted material.  Some even use 1/2" bits to rout for 3/4" shelving to prove the point.