reinforcing a shelf

[Wade Lippman]

I am building a 52 inch butternut shelf and putting a 55 pound TV on it. That is obviously way too much weight, so I am going to reinforce it with a .75x.75 inch steel tube. I have in mind routing a .75 inch wide .375 inch deep slot for the tube. Does that seem adequate? Two tubes?

[Yonak Hawkins]

Wade, help me to understand your plan. You're going to have a shelf that is 52" wide by (if it's a flat screen, the shelf could be 8" deep or so and, if it's a glass-tube TV, it could be as deep as 18" ~ 20"). ..So, you must have already figured out how you will attach it to the wall (that's the big issue, I'd say). I would think the main attachment brackets would be directly under the weight of the TV, or just to the outsides of it.

No matter what type of TV you have, the brackets couldn't be that far apart, I wouldn't think. Really, then, if my assumptions are correct, the question would be how do you support the outer parts of the shelf that are not directly under the TV weight ? What will you have out there and what will it weigh ? Could a wooden apron do it or would you have to have more brackets, or both ?

To respond directly to your question, I would think a metal tube would be more than adequate, should you decide to go that way.

[Wade Lippman]

The shelf is 52" wide; 12" deep. It will be supported only at the ends. I haven't given any thought to how the ends are supported, but 50 pounds isn't all that much; its just that 52" is pretty wide and butternut is pretty weak.
I checked out a steel tube at Lowes today and it is plenty strong; so if running a tube half buried the length of the shelf is a reasonable thing to do, then I am set.

However Lowes only had 1" tube and I wanted 3/4". What sort of supplier would carry it?

[Lee Schierer]

Instead of a tube, why not add a wood rib under the shelf front and rear. 3/4 thick by 1" high rib will add at least as much strength to your shelf as the steel tube you propose. According to the sagulator (http://www.woodbin.com/calcs/sagulator.htm) you 52" butternut shelf will sag less than 0.1 " with just one wood stiffener.

[Adam Diethrich]

Instead of a tube, why not add a wood rib under the shelf front and rear. 3/4 thick by 1" high rib will add at least as much strength to your shelf as the steel tube you propose. According to the sagulator (http://www.woodbin.com/calcs/sagulator.htm) you 52" butternut shelf will sag less than 0.1 " with just one wood stiffener.

Yes...

52" is pretty wide for a shelf, and if (guessing) only 3/4" stock will look flimsy.
How about taking this opportunity to build in some mass (thickness) and stiffness/strength into the design?

A.W.D.

[Sam Murdoch]

Yes to Lee's idea, and if you add glue and/or increase the wood "rib" to 1-1/2" or 2" even more strength and better looking in proportion to the size of the shelf and the TV above. Add a 1-1/4" under at the back and a 2" one attached with biscuits or dominos or just glue to the front edge flush to the top face and you can add tchotchkes to the shelf along with the TV :).

[Wade Lippman]

We have a wall with a woodstove on it. On one side is:
273922

The current project is to build a similar unit for the other side, only the 3rd and 4th shelves will be missing (that is where the television goes) and the bottom shelf will be 8" higher. Firewood will go in a bin under the television. At the top there will be 3 "sides" (okay, what are the parts the shelves go on called?), but I wanted to leave the bottom open to increase the amount of firewood that can be stored.
Maybe that isn't a good idea and I should have a third "side" below the television.

But I don't want to make the bottom shelf thicker than the all the rest.

[Sam Murdoch]

Let the firewood bin have a center "side" that also supports the TV shelf. In other words build the firewood box as 2 boxes. Maybe even build 3 bins so that you can recreate the look of the 4 legs, but yes the TV shelf above will be open to the outside legs. You can pick up the 4 leg detail from the shelf above the TV.

[Sid Matheny]

Maybe not what you want but you could wall mount the TV at the same level as the top shelf.

Sid

[Yonak Hawkins]

I can't tell from the photo if this is attached to the wall.

[Wade Lippman]

Maybe not what you want but you could wall mount the TV at the same level as the top shelf.

Sid

I considered that; even bought a wall mount. Then Amazon came out for 20% less than the Bestbuy price and BB refused to match, so I returned it. Then I decided against wall mount. But yeah, it might be a good solution; but certainly a more expensive one than reinforcing the shelf.

No, it is not attached to the wall. One possible second project though is a cabinet to hold fire wood and the television; and two shelves attached to the wall above the television. My wife is concerned it will be too different than the first one.

[Rob Feldner]

This is my go to calculator for shelves if I think things might be a bit heavy. Quite honestly, I think you're ok without the tubing depending on the thickness and depth of the shelf. It's also pretty impressive what a bit of edging will do to increase the strength of a shelf.
http://www.woodbin.com/calcs/sagulator.htm

[John Lifer]

I think, like Rob, it is good. One solution that would be easier to accomplish, AND give you peace of mind would be to use a steel or aluminum flat let into a slot along the length. Something of the 3/4 x 1/8 size. Rout our cut with ts a slot half the thickness of the board.

[Adam Diethrich]

I think, like Rob, it is good. One solution that would be easier to accomplish, AND give you peace of mind would be to use a steel or aluminum flat let into a slot along the length. Something of the 3/4 x 1/8 size. Rout our cut with ts a slot half the thickness of the board.

A piece of flat wouldn't be very stiff in that size, or many for this purpose. Perhaps a hybrid approach with a piece of 3/4 x 3/4 (or other appropriate) angle iron or aluminum extrusion?

A.W.D.

[Wade Lippman]

This is my go to calculator for shelves if I think things might be a bit heavy. Quite honestly, I think you're ok without the tubing depending on the thickness and depth of the shelf. It's also pretty impressive what a bit of edging will do to increase the strength of a shelf.
http://www.woodbin.com/calcs/sagulator.htm
Going to 1' reduces the the sag to an acceptable amount. I have plenty to think about.

[Jim Matthews]

Would box section steel be stronger, resisting bending?

I would be anxious to add some sort of tip prevention, to keep the works upright.
http://www.mypreciouskid.com/anti-tip-tv-anchor.html

[Yonak Hawkins]

Since it will be attached to the wall anyway, you could drill holes in the back sides of the shelf and slide it onto pins attached to wall studs (lag bolts with the heads cut off ?). This same method, into the uprights, could be used to attach this shelving unit, and the other one for that matter, to the wall and keep them from racking. You would have to take care to make sure the pins were perfectly horizontal as well as the holes.

[Grant Wilkinson]

We did a similar approach to your original idea, but using steel angle iron. On a 3/4" thick shelf, we routed 2 x 1/8" dadoes the full length of the shelf. They were 1/2" deep. We epoxied 1/2" steel angle iron into the dadoes, and screwed them to the bottom of the shelf. The shelf was low enough that the angle iron being proud of the bottom of the shelf couldn't be seen. If that had not been the case, we would have routed a shallow 1/2" dado so that the angle iron was flush with the bottom of the shelf. This was a 60" shelf, supporting a middle weight of about 75 pounds, and it's held fine for about a year now.