C Channel for dining table build

[Mike Monroe]

To answer your questions;

1. I'd use steel. FWIW - I purchased steel C channel from a local welding shop at a very reasonable price, they even cut it to the lengths I needed. A machinist friend milled slots into the C channel for me and I spray painted them black. A very economical option vs. purchasing powder coated C channel online. It's not like one sees the C channel or even know it's there in the bottom on the table top.
2. 1/2" legs on the C channel should be sufficient, that's what I went with. I made a hair pin leg table out of some locally sourced red oak slabs. My table dimensions are 63" x 32" x 1.5". I installed two lengths of C channel in the bottom of the table for safe measure against future warping/cupping. My table looks something like the table at this website: https://www.modernlegs.com/make-desk...in-table-legs/

Also, I finished the table with Rubio Monocoat. I'm very pleased with Rubio Monocoat, from ease of application to look and feel of the finished product. The table is my home office desk and replaced one of those foldup plastic BORG tables.

[Edward Weber]

If your top is comprised of wide boards, what method do you use to make the mortise? I am assuming one length of tube going across the width of the table, but not exposed on the sides. So you could have some through mortises that could be quite deep if you have wide boards.

As I said, you could also drill round, through holes, for pipe, rod or dowels if the board it too wide to mortise. Easily done with a brace and bit.
With mortising, going from each side is usually the best method.
You actually don't have to connect all the way through. If you manage about 80% of the board, it will stay pretty flat.

Here is an outside table I made in 2013, basically a proof of concept for this type of construction. Would it hold up outside?
This is simple construction grade 2x4 cutoffs made into a top. I ran 1/2" wooden dowels through the strips for support. After 10 years outside, I just measured, and the center is 3/32" lower that the outside accross the grain. Flat enough for a 36" wide outside table.
Had this been inside in a climate controlled environment, I have no doubt that it would be as flat as the day I built it. (which is what the photo is)
img_2636a.jpg

[Bill Dufour]

Aluminum can be stronger then steel, it just has to be a little thicker.
Bill D

[Edward Weber]

Here is a retail version of a dovetail solution, much stronger than the widely used steel channel that's being used by many YouTubers.
https://www.hafele.si/en/product/dov...3/?PageSize=48
This approach can also be done with a three section wooden dovetail for slab tops.

[John Kananis]

On one hand, I really like that, on the other, how could you install that AND hide the entry point (on a slab)?

Also, can you expand a little on the three section dovetail? Ty.

Here is a retail version of a dovetail solution, much stronger than the widely used steel channel that's being used by many YouTubers.
https://www.hafele.si/en/product/dov...3/?PageSize=48
This approach can also be done with a three section wooden dovetail for slab tops.

[Edward Weber]

Left side install, right side install, center strip or screw to fill the gap.
There is no "sliding", this fits into a stopped slot.

[Richard Coers]

FWIW, aluminum has 1/3 the stiffness of steel. I'm certainly not advocating any C-channel, but if you must, use steel. Also, FWIW, a square tube will be about 4X stiffer than a C-channel of the same dimensions and cross section.

John

Finally, someone that is talking about real strength and not imagined fixes.

[Richard Coers]

Aluminum can be stronger then steel, it just has to be a little thicker.
Bill D

More like a lot thicker.

[Ole Anderson]

Shortly after the 9 minute mark

Yep. If Blacktail Studios use them on $17k pieces that is good enough for me. Go to 3:20 https://www.youtube.com/watch?v=8wYD...lacktailStudio

[John Kananis]

The guy definitely has the epoxy pour down to a science (which I don't care for but that's subjective and aside) but I've seen nothing else in his videos to convince me of any other skill/knowledge in his arsenal. Imho, the guy established himself on yt early in the epoxy trend, uses large surfaces (which also brings a crowd) and gets to charge that much because of his popularity on yt and not necessarily because he can trim a miter like a pro with nothing but a rusty nail lol.

[Edward Weber]

Finally, someone that is talking about real strength and not imagined fixes.

Let me add by saying that the channels everyone is calling "C-channels" are technically U channels, yes there is a difference.
Also about strength. The channel is only as strong as it's orientation (which is flanges pointing down in most all applications) and the holding power of the (4) screws used to attach it.

A dovetail system (wood or metal) is attached along it's entire length and can not loosen or strip in the same way as the above. The same applies to an internal stiffening system as well.

The ONLY reason this method has become so popular is because it's easy for most anyone to do.

JMO, YMMV

[Robert Banh]

In all but the most extreme circumstances, there is no need to introduce an external metal brace.
Mortise a hole through the blanks and insert a proper sized square tube. It won't bend, it can float and it won't bee seen. You can also do this with round rod or pipe.
This can all be inserted during glue up and will be unseen to anyone.

Routing out 3/4 channels and securing C-channel to the underside is a rather crude way to approach stiffening the top IMHO.

Can you elaborate on how to do this? I'm new to woodworking and am planning to make a 72" x 40" dining tabletop out of 6/4 white oak. In my research, I came across a table called the "Max Table" by designer, Max Lamb. It looks like he used metal rods as you described inserted into the tabletop prior to glue up. Here's a link to a overview of the table, showing the design. https://www.dezeen.com/2020/07/15/he...table-design/#
Screen Shot 2023-12-09 at 7.26.30 PM.jpg
This seems like it would be a nice idea since the metal rods would be hidden and they would not only allow for easier alignment during glue up, but strength to resist warping. It would be pretty easy to drill the holes using a dowel jig to the appropriate size & depth. I'm thinking 3/8" on a 6/4 board.
The problem is I can't find any other info regarding this method and with my limited knowledge in wood working, I'm sure I'm missing something. Any help would be appreciated! Thanks!

[Edward Weber]

I saw this the other day and thought of this thread. This is basically the same way I've been using internal rods/dowels to strengthen tops, just like the small patio table I posted.
https://www.youtube.com/watch?v=OH86OiE15GI

[Prashun Patel]

I've used aluminum. I wouldn't do it again. It doesn't resist the force enough IMHO.

[Mark Gibney]

I just read the first page of this older thread. Did the OP ever tell us what he did? - I scanned the other pages but didn't see it if he did.

I'm made slab tables and I've never felt the need for embedded steel cross-stiffeners. So I'm with Andrew on this.
Will the tabletop be secured to an apron frame? Won't this provide enough bracing?
And cannot steel stiffeners be hidden behind the apron and surface mounted? - this would provide a lot more thread of the screws to hold the stiffeners in place, and for sure that's really crucial.