Pocket holes ????

[Bob Schumacher]

I'm building a book shelf out of melamine and a painted face frame. My question is should I use pocket holes under the shelves or put a screw though the side into the shelves. The book shelf is going to be built in so no one will see the sides. I'm wandering witch way would be stronger?

[Ed Peters]

For concealed sides, always screw through. Less work and better mechanical connection. As to the screws, I would recommend the Promax screws from McFeeleys. The sawtooth pattern of the thread really bites into the wood without spliting and the head has little nubs under it to provide it's own contersinking.
Just a word on fixed shelves, I always mount fixed location shelves in dados. After the dado is cut, you can drill through from the dado side to provide properly located pilot holes without any layout lines or messy calculations. Easing the edge of the dado with sandpaper before assembly blends in any chipping and makes for a uniform planned look. A little glue in the bottom of the dado, send in the screws and you're golden.

Ed

[John Ricci]

If you used pocket holes from the top of the shelves and plugged the holes they would IMHO be the strongest given that the downward pressure on the shelves would be trying to push the screws into their holes. My .02Cdn.

J.R.

[glenn bradley]

In from the sides is my vote too. Better mechanical strength. Besides, its not often you can get away with it.

[Peter Quinn]

if you are using melamine i wouldn't count on screws alone as particle board doesn't hold screws well. Create a mechanical connection using dowels or biscuits and screw from the sides on a built in with blind sides. Attach the face frame if it has one with pocket hole screws.

Confirmat screws are a good choice with melamine as well but require a special stepped drill bit.

[Ed Peters]

If you used pocket holes from the top of the shelves and plugged the holes they would IMHO be the strongest given that the downward pressure on the shelves would be trying to push the screws into their holes. My .02Cdn.

J.R.

If you would sketch up your suggestion in your mind I'm sure you will agree that this is way wrong. If you create a pocket hole and then cut it down the middle you will see that using the pocket hole on the top side leaves very little actual material to accept the weight the shelf will be subjected to. In plywood, you MIGHT get away with this but in partical board (typical core of most melamine products), not a chance. The downward pressure is not attempting to force the screws into the sides. It is going to sucessfully seperate the small web of partical board trying to support the weight of the shelf and it's contents from the bulk of the shelf.

Ed

[Steve Clardy]

Conformat screws from the side

[Larry James]

For concealed sides, always screw through. Less work and better mechanical connection. As to the screws, I would recommend the Promax screws from McFeeleys. The sawtooth pattern of the thread really bites into the wood without spliting and the head has little nubs under it to provide it's own contersinking.
Just a word on fixed shelves, I always mount fixed location shelves in dados. After the dado is cut, you can drill through from the dado side to provide properly located pilot holes without any layout lines or messy calculations. Easing the edge of the dado with sandpaper before assembly blends in any chipping and makes for a uniform planned look. A little glue in the bottom of the dado, send in the screws and you're golden.

Ed
I agree with Ed. If you have fixed shelves use dados, your face frame will cover the dado and it is much easier to ensure the screws are centered. If the sides and not visible, use the Promax washer head screws. Have you considered the load and length for the shelves? Sagulator (http://www.woodbin.com/calcs/sagulator.htm)

Larry

[John Ricci]

If you would sketch up your suggestion in your mind I'm sure you will agree that this is way wrong. If you create a pocket hole and then cut it down the middle you will see that using the pocket hole on the top side leaves very little actual material to accept the weight the shelf will be subjected to. In plywood, you MIGHT get away with this but in partical board (typical core of most melamine products), not a chance. The downward pressure is not attempting to force the screws into the sides. It is going to sucessfully seperate the small web of partical board trying to support the weight of the shelf and it's contents from the bulk of the shelf.

Ed

Ed, after re-reading the OP I would have to agree with you. My brain was thinking solid wood and not particle/melamine which would most likely break under pressure...ignore my previous less than thought out post:o

J.R.

[Bob Schumacher]

First off, Very cool web site Ed. I will use it often. Thank you. The shelves are about 30 inches wide and 18 inches deep. The load will be light, art supplies for a 8 year old.

I was hoping to not have to cut dados, but I do not want it to fail either. I will be fastening it from both sides, the back, and pocket holes to the face frame for a total of 8 screws per shelf.

If I was to cut dados into the sides, how deep should they be? is 1/4 sufficient? I would need to cut them with a router.

Again thanks for all the imput

[Jim Becker]

1/4" grooves for insetting the shelves in the sides is perfectly adequate, Bob. You can use the pocket screws to fasten your face frames, but be sure you also glue them. As previously stated, pocket screws and particle board is not the best combination. The glue will do the real work.

[Peter Quinn]

First off, Very cool web site Ed. I will use it often. Thank you. The shelves are about 30 inches wide and 18 inches deep. The load will be light, art supplies for a 8 year old.

I was hoping to not have to cut dados, but I do not want it to fail either. I will be fastening it from both sides, the back, and pocket holes to the face frame for a total of 8 screws per shelf.

If I was to cut dados into the sides, how deep should they be? is 1/4 sufficient? I would need to cut them with a router.

Again thanks for all the imput

A 1/4" dado is fine, and probably the quickest way to do it. Big shops use machines to punch dowel holes or confirmat holes quickly, it would take a bit longer without a line boring machine but can be done. For frameless you could use stopped dados. You do not need dados, but you should use more than just #8 screws from the sides. Dados, biscuits, dowels, confirmat's, pick the one that works best for you.

You could also edge band the fronts with paint grade solid wood 1 1/2" thick to stiffen the shelves and pin small triangular cleats from below, using melamine glue as an adhesive (roo glue?). The cleats are largely hidden by the edge band and provide speed and strength.

[Bill Keehn]

First off, Very cool web site Ed. I will use it often. Thank you. The shelves are about 30 inches wide and 18 inches deep. The load will be light, art supplies for a 8 year old.

I was hoping to not have to cut dados, but I do not want it to fail either. I will be fastening it from both sides, the back, and pocket holes to the face frame for a total of 8 screws per shelf.

If I was to cut dados into the sides, how deep should they be? is 1/4 sufficient? I would need to cut them with a router.

Again thanks for all the imput

Bob, actually I think screws drilled in from the outside are dangerous in this application. I did built-ins for my girls' toy closet a couple years ago. Caught them climbing to the top soon after. I'm glad I over-engineered them. Imagine your kid climbing the shelf or falling onto it while playing and ripping it loose from the screws. Screws aren't especially good at holding onto endgrain or MDF or particle board. Screws also have very poor sheer strength and are likely to break if unsupported. You don't want her impaling herself on these.

You could probably use cleats. Screw and glue the cleats onto the sides and back of the case from the inside. Attach trim to the front of the shelf that extends down and hides the cleats. The trim in the front and the cleat on the back will help keep the shelf from sagging. If the back of the case is not strong enough to support a cleat, attach a strip under the back edge of the shelf instead.

Maybe an even better option than cutting dados or using cleats is to cut spacers that fit between the shelves and attaching them to the back and sides of the case. It gives the same result as a dado, except that its easier to do, especially if the case is already built.

-Bill.

[Bill Keehn]

Bob, speaking of safety, melamine has a wicked sharp edge when cut. You definitely need to do something to relieve the edge.