How many clamps?

I find that the more simpleminded the question, the more likely people here will argue about it. This should be interesting.

I'm finally getting ready to attach the face frames to my first two bookcase units. Apart from some pocket screws for the top and bottom rails (whose holes will never be seen), I plan to just glue and clamp. I took a first stab at laying out where the clamps should go. I find that it's a little less nerve wracking if I have all of the clamps at hand and set to something like the right opening before I apply any glue.

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and

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I have two questions:

Do I need three clamps for each rail, as shown in the photos? Or would two (plus the clamps at the ends of the rails) be enough? The units are 21" wide.

I have shown five pipe-style clamps on each side (one at each T intersection) plus some cheap bar clamps in between the shelves that are further apart. Do I also need clamps between the shelves that are closer together? Those are 11.25" apart on center.

I feel I'm going to get a lesson on cauls, which, if quick and simple, I could consider. But my spare time has become very spare indeed lately.

Thanks in advance.

Reply to
Greg Guarino
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Looks like enought to me if you use some cauls or blocks with those bar clamps.

Reply to
Larry W

You only need enough to eliminate/close the gap.

See above.

Calls would eliminate the need for so many clamps b

Reply to
Leon

On Sat, 23 Mar 2013 21:19:32 -0700 (PDT), Greg Guarino

Despite the holding properties of proper glue usage and clamping, I'd never just glue on any part of your project. Almost everything I build, I overbuild. To that end, I'd use my Domino and/or my Kreg wherever possible.

But, if I was just gluing, I'd clamp the face frame enough to close any gaps.

Reply to
Dave

Two would be enough, three won't hurt.

Why no clamps on top & bottom rails?

No.

Faster to eschew clamps and use countersunk screws and face grain bpugs.

Reply to
dadiOH

I find that the more simpleminded the question, the more likely people here will argue about it. This should be interesting.

I'm finally getting ready to attach the face frames to my first two bookcase units. Apart from some pocket screws for the top and bottom rails (whose holes will never be seen), I plan to just glue and clamp. I took a first stab at laying out where the clamps should go. I find that it's a little less nerve wracking if I have all of the clamps at hand and set to something like the right opening before I apply any glue.

formatting link

and

formatting link

I have two questions:

Do I need three clamps for each rail, as shown in the photos? Or would two (plus the clamps at the ends of the rails) be enough? The units are 21" wide.

I have shown five pipe-style clamps on each side (one at each T intersection) plus some cheap bar clamps in between the shelves that are further apart. Do I also need clamps between the shelves that are closer together? Those are 11.25" apart on center.

I feel I'm going to get a lesson on cauls, which, if quick and simple, I could consider. But my spare time has become very spare indeed lately.

-------------------------------------------------- Other than use biscuits to maintain registration between carcass and F/F, what does your gut tell you?

Lew

Reply to
Lew Hodgett

Well, they could be seen, if one were to look under the shelves. This will be easy to do for the upper shelves, as these units will rest on existing boxes that raise them up about 30". The top shelf will be above eye height, at least for height-challenged folks like me.

The better question is why I shouldn't use pocket screws for the stiles, drilled in from the outside of the boxes. These two bookcase units will be flanked on one side by another bookcase and on the other by the side walls of the room. The answer is that I did consider it, and haven't entirely rejected the idea. I just wonder if I'll regret it someday. By Murphy's Law, putting pocket holes in the outside walls of the cabinets will guarantee that we'll need to re-purpose them at some point; the new configuration exposing the sides.

Now this is a pretty minor concern, and I could be convinced otherwise if I thought it was structurally necessary to reinforce the glue. Is it?

Reply to
Greg Guarino

That's one of the reasons that I made all of the shelves fixed, in dadoes. My experience is limited, but I have trouble imagining these boxes failing with so many glued joints. They will also have backs, rabbeted in, and the face frames.

Reply to
Greg Guarino

I have a few ideas on the subject of "gut". What we call "gut" or "feel" is a mental association built up over multiple repetitions of some observation or activity. It's what allows people to accomplish tasks that are too complex for conscious calculation, like hitting a curve ball, or playing music without a written score. (In my case, that would be "yes" for the latter, "no" for the former)

I think I have developed a reasonable mechanical sense over the years, and what "gut" I have tells me that it will probably work fine, even with fewer clamps than I show. But I am always willing to learn from people with better-developed "guts".

Reply to
Greg Guarino

It's hard to use too many, and easy to not use enough.

Base it on the material, and the particular job ... if there is any doubt whether you have enough by the way the job is clamping up (as in is some of the material bowed and not making good contact?), add more to those spots, it will rarely hurt to do so; if not, don't worry about it.

Your photos appear to be just about right for most face frame glue-ups.

Just remember, to effectively glue two wood parts together with most modern wood glues you need both contact between the parts, and adequate pressure (which may vary with the application).

Reply to
Swingman

Coming from someone (me) who generally over-engineers everything, your statement in way too general to be good advice. :-)

You said it yourself in your first sentence, "Despite the holding properties of proper glue usage and clamping..." If there's no load on a joint, it's just plain silly to use dowel/tenons or screws for strength. In any non-load bearing joint, if the glue alone isn't strong enough, the joint isn't designed properly. Even a butt joint with modern glue is strong enough.

Unless they are serving another purpose, screws or dowels/tenons are a waste of time and resources. Tenons for alignment are a another story. They are great way to help perfectly align a joint while clamping or until the glue cures.

Pocket screws are a great way to clamp, but according to Kreg and confirmed by my experience, they negate the need for glue. I use pocket screws to clamp all the time, in places they won't be seen, when I don't have enough clamps or I don't want to wait for the glue to cure before moving to the next step in the project. Sometimes, after the glue dries, I'll take the screws out and recycle them because the are no longer doing anything useful-- they were simply tiny clamps.

For the OP's bookcase project, assuming he used dado joints for the shelves, I see nothing that requires anything other than glue for strength and holding.

Reply to
-MIKE-

Of course you realize that there is no hard and fast rule. and opinions will vary.

I have no rule. Just what I feel. Sometimes I over clamp... looks like a porcupine, sometimes not. Cauls are nice if you have them made ahead of time. I tooks some 2x4's and ripped them in half then I planed them so that they have a nice bow. so one side is flat and one arches. I use either depending.

Now that I haven't given you an answer, are you finishing the face frame first? or after?

Reply to
woodchucker

"-MIKE-" wrote:

------------------------------------------------------------ With the advent of modern day adhesives, the relative strength advantage of fastners v. adhesives for joints is greatly over rated.

Ever wonder how Boeing is securing all that carbon fiber they are using to build the current airplanes they are producing?

Think maybe various epoxy formulations might be involved?

Adhesive for shear load applications is a tough joint to beat.

Tensile load joints, not so much, but then tensile joints are no winner for fastners either.

Lew

Reply to
Lew Hodgett

Greg, see the binaries...

Reply to
woodchucker

True, and I did consider doing that. But it turns out that the plugs are a little too long for 3/4" material and would need to be cut down. And as I stained the ply, they'd have to be stained as well, and surely wouldn't quite match. All of that could be acceptable if I was convinced that there was some need. But my sense of it is that the glue alone will be adequate. I could be wrong; a common enough occurrence when the topic is woodworking.

Reply to
Amy Guarino

No binary access. I use Eternal September on one computer and GG (until I get around to fixing it) on this one.

Reply to
Amy Guarino

First. They're done, actually.

Reply to
Amy Guarino

On Sun, 24 Mar 2013 11:50:15 -0500, -MIKE-

The cabinet sides and shelving are plywood. That being the case, he would be gluing hardwood face frames to plywood edging. Maybe I've been doing something wrong all these years, but I've *never* been able glue wood to plywood edging and been able to call it a strong connection.

That's my reasoning for more than just glue.

Reply to
Dave

On Mon, 25 Mar 2013 06:51:25 -0400, "Mike Marlow"

Oh, I'm not saying that the face frame will move, just that my building preferences demand that most of what I build are comparable to a tank.

Reply to
Dave

Greg see the first two images in:

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Just meant to show that cauls can be simple and also used for other things. I turn them around at times to lightly clamp for dovetailing.

BTW what stain did you use on your inside. I like the color.

Reply to
woodchucker

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