Fitting Shelves into Dado Joints

[Pat]

Unfortunately "even using the router jig I built", the dado I made for a shelve to fit into, is just a tiny bit larger than expected. I think the UHMW plastics I used deflected a bit. I should have used wood. Would have been less expensive too.

So the end result, the joint is more of a slip fit, rather than a tight fit. With the shelf in place, I can probably slide a couple of folded sheets of paper into the joint.

So what I'm thinking about trying is to expand the end grain of the "Red Oak" using a hot iron and wet rag, and basically swell the wood to tighten up the joint.

It's only the one shelf that is affected. Only the bottom half of the shelf will be seen. The rest (top) is hidden. I have also thought about putting a shim into the top between the dado and shelf.

Any ides or is there a better way to tighten up this joint.

Pat

[toller]

I have used shims. It feels real crappy to do, but worked okay.

[Upscale]

You might try some of Lee Valley Tools' chair glue. It's designed for swelling loose tenons of chairs and it dries in the swelled state.

[bridger]

cut a single long shaving with a plane. use that for a shim.

[Pat]

Darn, that's a good idea and I can fix my wobbly chair too. I don't know how many times I've gone through the site "Spending Money" and I have not seen this product.

Thank You....

[Pat]

See the post from Upscale regarding Lee Valley's Chair Doctor Glue. It sounds like it would be perfect for this task. er ah, problem..

Thanks...

[igor]

[George]

How loose? Two thicknesses of 80# paper? That's easily within the expansion range of any water-base glue, not to mention the hold is at the end of one board and bottom of dado. Gravity would suggest that you assemble with the bottom down, so if there is a gap, it's at the inconsequential upper part of the joint. Cover with tape, solid stock, or just fill and paint as required the front as required. Won't affect the overall. If the gap is visible, stuff it with dust before you finish.

Now, someone should have reminded you that modern ply is almost always undersize. They even sell undersize bits to cater to it.

Next time.

[George]

Unfortunately "even using the router jig I built", the dado I made for

[David Hall]

Cut a slot in the end of the shelf board about as deep as the dado. Then cut a strip the same width as the depth of the slot. The thick edge of the strip should be "a couple of folded sheets of paper" or so thicker than the slot you cut and tapered to a little thinner than the slot at the thin edge (a couple passes with a block plane will accomplish this tapering). Then when installing the shelf put a little glue in the slot, set the strip, thin edge first, into the slot - don't force in in at all, it should set proud of the shelf edge. Then put the shelf into the dado and whack it in (rubber mallet, etc. not to mar the wood) this will set the wedge and widen the edge of the shelf in the dado. This is NOT a good thing to do if the issue is more than a couple sheets of paper as it could split the shelf board but sounds like it would work in your described situation and be invisable.

Of course, the shim at the top as you described seems easier and also won't be seen.

Dave Hall

[Pat]

Hi Dave,

First your response to "Need Psychiatric Advice" was absolutely excellent. I must keep a copy of that post.

As for my problem. "Upscale" suggested I try Glue Doctor available from LV. On end grain it causes the fibres to swell and then set's in the swelled position, thus fixing poor joints in chairs etc. And frankly, I have one wobbly chair kicking around as well, so it might be a very workable fix.

As for psychiatric advice - I might be being a bit too picky as well. But I wanted a nice tight joint for the shelves. Even though there will be a face frame over the actual joints.

I also tried my router jig "a second time". Darn thing was 99.9% perfect on the second dado. I guess it gets better with age.

Pat

[Pat]

Paint Red Oak "God Forbid" a 1" x 8" x 96" board cost me $50 CDN

"Upscale" suggested Glue Doctor from LV, which is made to swell the fibres of the end grain and sets in the swelled position. I think that's a better alternative to try.

As for the rest. I was using solid stock, not veneer ply. I had even built an adjustable dado jig for my router, which was made specifically for the bit and router I'm using. What went wrong and caused this little problem is beyond me. The second dado, which I routed at a later point, after double checking the jig and getting everything clamped in place, was 99.9% perfect.

Thanks for your reply...

[Charles Lerner]

Although it's probably overkill, what I've done in the past is to glue a thin strip of wood at the bottom edge of the loose shelf and then plane the strip with a handplane until the shelf fits just right. This way you effectively make a perfect-fitting shim.

Charles

[patriarch]

Pat wrote in news: [e-mail]:

WHERE are you buying your material? That's over twice what I spend on s3s FAS 8" & wider red oak, even after allowing for the differences in the value of the US vs CDN dollars. And I live in a classic 'high cost' area...

Oh, well. The price we pay for the hobby to which we are addicted.

Patriarch

[Pat]

Up here - That's what Home Despot calls S4S Red Oak.

It's $44.64 for a eight foot long 1 x 8 board. (3/4 x 7 1/4 x 96) Then add 15% in taxes. Total $51.34 $9.65 bd ft.

That doesn't include the planing or sanding you have to do afterwards to actually make it look like S4S board.

Unfortunately in my area, there's only a few places kicking around to buy wood.

There is one "true" supplier, a mill. The prices aren't much different than Home Depot, and in their case, Cherry is $15 a bd ft, and you still have to add 15% to that for the taxes.

Yes, this is an expensive hobby.

Like I wrote previously - this oak ain't getting painted. {Smile}

Pat

[George]

Even there you're in some strange territory, unless you plane your own. At $8/ft I assume you bought it done somewhere else. Might even have been sanded, thus undersizing. I think the chair joint stuff is overkill, personally, but it will probably work fine.

Answer to precision is the router jig, no doubt. I use the guide and plunge with parallel strips for adjustment like the Router Workshop types, though doing my own planing helps the fit a lot. On small stuff I'm as likely to dovetail as dado. Same jig, better hold.

[Old Nick]

On Mon, 26 Jul 2004 13:44:21 GMT, Pat vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

Phhhht! Start again!

***************************************************** It's not the milk and honey we hate. It's having it rammed down our throats.

[Old Nick]

On Mon, 26 Jul 2004 13:44:21 GMT, Pat vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

Seriously. Never try a new techinque on a piece of work....

***************************************************** It's not the milk and honey we hate. It's having it rammed down our throats.

[Nova]

... or glue in a thin strip at the bottom edge of the dado and re-route the dado to the proper size.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)