Can you use router table to cut dados?

[lcm1947]

Everything I read lately seems to indicate that dados are supposed to be cut by a hand held router when using a router of course not a table saw. I am talking router here not table saw. Is there a reason for not using the router table? I just got through cutting two dados in my router fences for some T-track and didn't seem to have a problem but was it dangerous or something? The fences were only maybe 24" long though. Maybe they're talking about really long stuff?

[John Hunter]

I cut dados all the time on my router table.

[beetee3]

For long pieces it's usually easier to keep the workpiece stationary and move the router. For smaller pieces the router table works just fine. Much the same reason as why most folks choose to do the initial cuts on full sheets of plywood with a CS rather than wrestling them across the tablesaw.

[RodKirby]

I cut dados all the time on my router table.

Ditto! 3456789

[LCHIEN]

again this comes to the wisdom that comes with experience. I prefer to cut dados on the table saw, but for a quickie I will do one on the router table. I seldom do them handheld.
But what makes the choice for me I have mentioned over and over again is the relative convenience of moving the wood vs. moving the tool.

Say given a 12" long 1x2 that I needed a 1/2" dado down the middle.
I'd do it in a flash on the router table because it's too small a piece to set up and clamp it where the router would be clear to move and be able to clamp a guide to it to handhold the router. With a table-router and a fence and a couple of push blocks I can do that guy in a minute of setup.

OTOH, making a series of shelf rabbets in the 12" x 6 ft bookcase slab sides I would sure use a clamp on guide and a hand held router.

[leehljp]

Giving a little different take that Loring but in the same direction - There are two different cuts that require different approaches.

A router table will do dados on long pieces very similar to a table saw. For a 6 foot board with a dado (or rabbet) the length of the board, the saw or router table will be about equal and both will do a fine job.

For a cross cut dado the router table and saw table will do close to the same quality, BUT the problem is that balance of the board and straight forward feeding on table saws and router tables are difficult when you are dadoing anywhere but from the center.


A hand held router with a jig will cut dados (cross cut) better than can usually be acheived with a table saw or table router on long pieces.

If a dado is being cut in the middle of an 8 ft board, then a table saw or router table can probably handle that easily. But when the cross cut dado is towards the end of the 8 ft or 6 ft board, it is very hard for most people to hold the board straight when feeding it, even with a jig. For that reason, a hand held router with a jig is more effecient for most people in this circumstances.

Hand helds are better in some cases, tables in another.

[JSUPreston]

Did it last week for a 40-50 year old desk that I am rebuilding. I was replacing the drawer sides and since the original had the drawer bottom in a dado, I thought I ought to do the same. Worked great. However, need to get a sled for the router table to cut the rabbits next time.

[mschrank]

One point I didn't see in the responses above is that you need to think a bit when using a router table to widen dados. If you are only making one pass (that is, your bit diameter exactly matches dado width), then no problem, feed as normal.

But if you have to make a second pass to widen, make sure you move the fence BACK and not forward. If you move it forward, you are effectively making a climb cut and trapping a portion of the workpiece between the bit and the fence. This is not good.

[Tom Miller]

Ditto! 3456789

Rather verbose, don't you think, Rod?

(You only needed the 345, and maybe the 6. )

Regards,
Tom
p.s. Ditto on the router table for dados -- whatever works.

[lcm1947]

Thanks for the replies everyone. I got it and it makes sense now but just had to ask in case I was missing something. Now Preston if I may ask, why a sled? What's wrong with using the fence for rabbits? I don't get it. And mschrank, I didn't get that about the climb cutting at all and trapping the project between the fence and bit. Don't you always do this on any cut? When you cut even a one pass dado there's stock between the fence and bit, isn't there? Could you elaborate some on this?

[JSUPreston]

If your doing a rabbit along the short edge of a piece, it has the tendency to twist, similar to kickback on a table saw. I may be wrong, but I believe it is caused by the leading edge of the bit trying to pull the wood into the fence. On a long piece, you would have enough riding against the fence that you could probably hold it (use a fingerboard if at all possible), however the short pieces will actually pull away from you and then possbily get shot across the room towards you. The only other way I can describe this is to imagine the workpiece rotating clockwise, with the point of contact as the center. I personally tried this on the desk, and almost had an accident. I stopped just in time, so I may have the directions backwards, but trust me, without the sled this was a dangerous thing for me to try.

Since I don't have a sled yet, I set my blade on the BT3100 to the height of the dado, since that was also the height of the rabbit. Using a stop block and the SMT, I was able to get a nearly perfect rabbit, safely.

[RodKirby]

Rather verbose, don't you think, Rod?

(You only needed the 345, and maybe the 6. )

Regards,
Tom
p.s. Ditto on the router table for dados -- whatever works.

I do try to be concise, Tom (at least that's more than 10!)

[mschrank]

And mschrank, I didn't get that about the climb cutting at all and trapping the project between the fence and bit. Don't you always do this on any cut?

No. If you are, say, putting a roundover on a 2" wide piece, you don't set the fence 2" from the bit, do you? No, you set the bit into the fence and run the edge you are cutting along the fence.

When you cut even a one pass dado there's stock between the fence and bit, isn't there? Could you elaborate some on this?

Well, yes. But, one the first pass, the bit is surrounded by wood so the forces exerted on the stock are basically "even." If you need to make a second pass to widen the dado, the bit is no longer surrounded by the wood...it's only contacting on one side. If you move the fence closer to the bit to make this second cut, the bit is then cutting the "far" side of the existing dado, which creates the climb cut situation since the rotation of the bit will be trying to move the stock in the same direction you're feeding it.

If you move the fence away from the bit, it is cutting the "near" side of the existing dado and rotating against the right-to-left feed direction...which gives you more control. Yes, you will have stock between the fence and bit, but it is not in contact with the bit.

Illustrations would help here...maybe I'll try and draw some up later if you like.

FYI-I (and others) highly recommend Woodworking with the Router by Bill Hylton. It's only about $19 on Amazon.

[Tom Miller]

If your doing a rabbit along the short edge of a piece, it has the tendency to twist...

Right -- the problem is really that there's not enough stock against the fence to control the cut.

In this case, rather than using a miter slot sled, a standard method is to use a square panel (10" - 12" on a side) against the fence. One edge rides along the fence, and the workpiece is butted up to the leading edge of the panel, with it's end against the fence. The panel serves to keep the workpiece square to the fence, while also acting as a backer board.

Even though I had installed a miter slot on my first router table, I prefered the above method. I didn't install a miter slot on my second table.

And Mike makes a very good point about taking care in widening dados!

Regards,
Tom

[JSUPreston]

[quote=Tom Miller]Right -- the problem is really that there's not enough stock against the fence to control the cut.

In this case, rather than using a miter slot sled, a standard method is to use a square panel (10" - 12" on a side) against the fence. One edge rides along the fence, and the workpiece is butted up to the leading edge of the panel, with it's end against the fence. The panel serves to keep the workpiece square to the fence, while also acting as a backer board./quote]

Tom, thanks for the reminder. I'd forgotten about that method. I was thinking a miter sled since I got one of those Bosch/Craftsman tables a couple of years ago. It's got a miter slot...so I was thinking about something to ride in it. If I get a little time in the shop this weekend, I may build a square panel. Got a good bit of 1/4" ply left over from the desk. I think that thickness would work well.

BTW: If that router table ever goes on sale again, I'd suggest looking into it. It was a great deal. I really like having a true router table as opposed to some of the cheaper package deals like Skil or B&D.