Tabletop question

[Shayne]

I am building a table that will serve as an entertainment center. The table top will be six foot wide and about 18 inches deep and 1 inch thick. Directly under the top I'm putting a shelf which is a little smaller to hold all my A/V components. There will be vertical panels on each side and then two more 12 inches on each side of the center which will box in the center speaker. I understand that wood movement could cause the tabletop and the shelf to contract and expand so I don't want to glue the top or shelf to the vertical panels. My first thought was to dovetail the vertical panels into the shelf and the top and not apply any glue. But that scares me since the two pieces are so large and I'm afraid of screwing them up. Then I remembered from my table construction class at Woodcraft that with the smaller Shaker table we built that we used table top fasteners to attach the top to the case. So my question is will the fasteners work on a larger table like I am building and if so how many do I use, one every 12 inches? and does it matter where I get them (i.e. Woodcraft, Klingspor, Rockler, etc)? If I use the fasteners, do I need to worry about when I pick up the table to move it that the top will be a little loose? I expect this piece to be heavy in the end and I would likely pick up the table by the top since that is the obvious way to move furniture.

Are there any other viable options that I haven't thought of?

Thanks in advance
Shayne

 

[DaveO]

Table top fasteners, either "Z" clips or figure 8's, will work just fine. But as you mention they probably will not hold the top to the carcass as firmly as other jointery methods. They will hold well enough for you to move the piece about by the top at the spacing of 12" apart, if the screws are long enough.
Sliding dovetails would be the best way to go about it, and they would help to keep the top flatest. They really aren't that hard to do if you practice all your cuts on scrap first. That way your errors won't mess up a lot of wood.
MTCW,
Dave

 

[walnutjerry]

Are there any other viable options that I haven't thought of?

Thanks in advance
Shayne

Shayne--------There are other options. I use cleats and struts underneath table tops. The cleats are fastened to the inside of the long aprons with screws. The struts are fastened on top and at right angles to the cleats using screws. With 6' length and 18" depth I would use 4 struts with 3 screws per strut. One screw in the center with no slop and one screw near each end in an elongated hole. That arrangement of screws keeps the table top centered and equilizes the movement on either side of center while holding the top down snuggly to the frame. I also use a washer under the screw head of the screws in the elongated holes. That helps allow the natural movement in my opinion.

This is not the fastest way to attach a table top---it is more in line with the traditional way of doing it though. I guess it is a matter of opinion which way is the "best".

Good luck on your project---------hope we will see some pics of it.

Jerry

 

[DavidF]

A sliding DT is the way to go on this one especially if you ever intend to lift it at all with the A/V equipment in place. They are not difficult to do on a router table. Do the male side first and then sneak up on the other side until the fit is good. A little wax helps when driving it home or the tendency is to make it sloppy in order to get them together. A tapered sliding DT is the answer to that one, but we are then talking about a whole new set of challenges!

 

[Gofor]

Am I missing something? (Probably!!)
If the supports have the grain running vertically, the shelves have the grain running lengthwise, the top has the grain running the long direction, and they are the same wood, why would expansion be a problem. All the pieces will expand across the depth at the same rate. Altho glue may not expand well on that long a joint, pocket screws should be okay for fastening.
From the description, I see no areas where the grain in adjoining pieces is running at 90 degrees to each other.

:-?

Go

 

[DavidF]

Am I missing something? (Probably!!)
If the supports have the grain running vertically, the shelves have the grain running lengthwise, the top has the grain running the long direction, and they are the same wood, why would expansion be a problem. All the pieces will expand across the depth at the same rate. Altho glue may not expand well on that long a joint, pocket screws should be okay for fastening.
From the description, I see no areas where the grain in adjoining pieces is running at 90 degrees to each other.

:-?

Go

I would imagine that the grain of the dividers will be running front to back. They certainly could go the other way, but you would then end up with an end grain glue up which would be no good in this application, or even using pocket screws, the penetration into the top would be insufficient to hold together when it is being lifted by the top as mentioned.

 

[Gofor]

Thank you David. Still learning, so still askin' questions.

Go

 

[Shayne]

Thanks for all the opinions. I think will be a man and try the sliding dovetails. I am curious to know more about the cleats and struts idea though. I've never heard of such things and some quick searches didn't give me any leads. Could you maybe explain and/or provide some pictures?

I will post some pictures when completed.

Thanks for everyones help!

Shayne

 

[walnutjerry]

I am curious to know more about the cleats and struts idea though. I've never heard of such things and some quick searches didn't give me any leads. Could you maybe explain and/or provide some pictures?

I will post some pictures when completed.

Thanks for everyones help!

Shayne

Shayne--------I do not have any pics of the cleats and struts on file but time permitting I will try to post some soon.

I am not the best with words so I really don't know how to explain it any different than than I did in the previous post--------sorry.

Jerry

 

[DavidF]

Thank you David. Still learning, so still askin' questions.

Go

Aren't we all:lol:

 

[Shayne]

So I cut the sliding dovetails and everything looks good so far. I think I remember seeing Norm or someone do something like this and I think I remember they glued the last few inches. Is this the right thing to do or no glue at all??

Thanks
Shayne

 

[DaveO]

Yea, it's a good idea to glue the last few inches just to make sure that the top stays in the right place if the DTs get a little loose. Depending on what type of a table it is, and where it will be placed might dictate where you want to glue. For example, if the table will be up against a wall you might want to glue the back so any expansion occurs to the front.
Dave