Dados with the router

[Sgian Dubh]

An alternative and stronger joint is a common or garden tongue and housing describing precisely the situation where the recess runs across the grain. The term dado, incidentally, is an Americanism that many Americans don't even know how to use correctly, so there's little point in the British adding to mangling of the word's use, ha, ha. A tongue and groove describes the recess following the length of the grain.

Run whatever cutter you have to hand for the housing or groove, eg, 6, 8, 12 mm, and then work a tongue to suit on the end of the matching part, eg, shelf, carcase side, panel, and so on. The joint is stronger because of the increased gluing surfaces and the number of right angled returns that help hold the parts square to each other, and lock the joint during and after assembly. Slainte.

 

[j]

This shouldered one is the way I've done it in the past, but only because I didn't have a router bit as think as the wood I was using.

However, It is a lot of extra work, as you now have to machine both pieces.

J

 

[Sgian Dubh]

However, It is a lot of extra work, as you now have to machine both pieces. J

J, it can seem like more more work, but on the other hand it's reliable as you always get a good fit. The full housing, even with all the jigs to guide a router tend to be unreliable in my experience because of things like differences in board thickness, or dust getting into the jig. A sloppy or tight joint due to factors like this puts the maker in the position of making a choice between a bad fit and/or a weak joint, or doing something to fix it. By the time the fix is done you're often better off doing the two part tongue and groove.

There are a host of ways to speed the job up doing the shouldered tongue. For example, if you need four shelves 300 mm wide and you're using plywood you can create the tongue on both ends of a full width piece of plywood (1220 mm wide) and later rip it to shelf width. This is just one trick. There are others.

I've never really found the full housing a satisfactory, reliable, or fast joint to make for high quality work compared to the shouldered tongue and housing/groove version. A major factor, for instance, that causes difficulty is assembly, especially where there a lot of joints to align at once. There's too much flopping about and the joints tend to be more difficult to line up than the tongue and housing or tongue and groove. Slainte.

 

[chippy1970]

However, It is a lot of extra work, as you now have to machine both pieces. J

J, it can seem like more more work, but on the other hand it's reliable as you always get a good fit. The full housing, even with all the jigs to guide a router tend to be unreliable in my experience because of things like differences in board thickness, or dust getting into the jig. A sloppy or tight joint due to factors like this puts the maker in the position of making a choice between a bad fit and/or a weak joint, or doing something to fix it. By the time the fix is done you're often better off doing the two part tongue and groove.

There are a host of ways to speed the job up doing the shouldered tongue. For example, if you need four shelves 300 mm wide and you're using plywood you can create the tongue on both ends of a full width piece of plywood (1220 mm wide) and later rip it to shelf width. This is just one trick. There are others.

I've never really found the full housing a satisfactory, reliable, or fast joint to make for high quality work compared to the shouldered tongue and housing/groove version. A major factor, for instance, that causes difficulty is assembly, especially where there a lot of joints to align at once. There's too much flopping about and the joints tend to be more difficult to line up than the tongue and housing or tongue and groove. Slainte.

Absolute rubbish my jig has never been unreliable its 100% reliable and its adjustable to any shelf size. Also as I said use dust extraction then you wont get dust affecting the accuracy of the jig. :x

Yes Dado is an American word and I only used it because the original poster used it. The correct term is housing or trenching but I am sure we all know what we are talking about. :roll:

 

[wizer]

Really going back and forth on this one. I may have to make some test cuts with an 18mm bit and see how good or bad it is. I'd like to use the mailee/Tony method, but speed is an issue here.

 

[Shadowfax]

Board width is irrelevant in this case. If you set the jig to the board width (by using the actual board) there is no way that the dado, groove, trench or whatever can be the wrong width.
This is one of the most useful jigs you can make for a router.
Cheers.

SF

 

[mailee]

I agree any variation in the board width is taken up in the jig as you 'clamp' the board between it. :roll:

 

[brianhabby]

Hi Wizer,

The jig(s) mentioned above are probably the best way to go about this task and well worth making. If you want to see some router jigs being made (including dado jigs mentioned above) you can check out this link.

By the way, what happened to your avatar?

regards

Brian

 

[wizer]

Thanks Brian, I will check that link out right now.

The avatar got lost in a website crash, i've been lazy in setting a new one. I'll get on the case.

 

[Tom K]

Yeah what about the thickness though (homer) Never mind its probably as wide as it is long eh!

 

[wizer]

How might one setup a Mailee TM Jig for rabbeting? Some sort of fence on the underside?

 

[Sgian Dubh]

Absolute rubbish my jig has never been unreliable its 100% reliable and its adjustable to any shelf size.

Fair enough chipp. I can't doubt that your jig is 100% reliable. I only mentioned the tendency of such devices to sometimes lead to either tightness or sloppiness in the joint because I've seen it.

It is something to look out for when working on large jobs and board thickness can, and sometimes does, vary from batch to batch. Slainte.

 

[mailee]

Not quite sure what you mean by set up the jig Wizer? If you look at my picture you will see I am indeed using it for a rebate. I first measure the line to cut to on the work piece and then use two clamps on the other side to make sure it doesn't move. At least I hope this is what you meant. :?

 

[Tom K]

Would'nt you just move the jig to the end of the board? Or use the "Quicky Router Table" and fence?

Regards Tom

 

[mailee]

Maybe this pic will help with the jig. you will see one end is fixed at right angles to the guide and the other moves on slots to accomodate the shelf.