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Table top with releaf cuts?

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Forum topic by TEK73 posted 05-26-2022 08:45 AM 490 views 0 times favorited 13 replies Add to Favorites Watch
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TEK73

411 posts in 1201 days


05-26-2022 08:45 AM

Topic tags/keywords: question joining oak

Hi

I’m renting a cabin, where they have a beautiful table, in a design I’m wondering about using the design from when making a table on my own
.
The table top is approximate 4cm thick in solid oak.
They have used steel bars to stabilize the top. That is a technic I know about.

But they have also made cut, maybe 2cm deep, below the table.
This is something I have not seen before.

Is there anyone that may share some insight/knowledge on this?
Why is it done and is it important to do?
In other words, should I do the same if I build a simular table top?

-- It’s good to have an end to journey toward; but it is the journey that matters, in the end. - Ursula K. LeGuin


13 replies so far

View corelz125's profile

corelz125

5540 posts in 2470 days


#1 posted 05-26-2022 11:11 AM

Could be to relieve tension in the slab to keep it flat.

View MrUnix's profile

MrUnix

9045 posts in 3693 days


#2 posted 05-26-2022 11:13 AM

Only time I’ve seen similar is on the old wood top Delta machinery stands, which had the underside of the 2x material scored in a similar way. They claim it was to improve stability of the wood and prevent twisting/warping. Got no idea if it works or not, but I do have an old Delta bench from around the 40’s and the top is still nice and flat ;)

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Lazyman's profile

Lazyman

9779 posts in 2881 days


#3 posted 05-26-2022 12:29 PM

If they used angle iron or channel, which provides extra stiffness compared to flat bar, I think that I have seen this done primarily so that the metal does not protrude below the bottom surface of the table. I doubt that it provides any structural advantage over having the angle or channel hang below the the table.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View TEK73's profile

TEK73

411 posts in 1201 days


#4 posted 05-26-2022 01:36 PM



If they used angle iron or channel, which provides extra stiffness compared to flat bar, I think that I have seen this done primarily so that the metal does not protrude below the bottom surface of the table. I doubt that it provides any structural advantage over having the angle or channel hang below the the table.

- Lazyman

The metal is a U-profile, bit the cuts I’m talking about are perpendicular to the iron U-profile.

It’s interesting as, based on the rest of the construction, those who buildt this table knew what they we’re doing, so I’ll expect they had something they beleived had a purpose.

-- It’s good to have an end to journey toward; but it is the journey that matters, in the end. - Ursula K. LeGuin

View bilyo's profile

bilyo

1563 posts in 2596 days


#5 posted 05-26-2022 01:52 PM

Just from the photos I’m making a big guess. I see a lot of stuff going on that doesn’t seem to pertain to an ordinary table top; cross pieces, brackets, etc. I also see the darker appearing panel in the center of the top. I think the table is made with removable stowable extensions and the grooving and metal pieces are a part of that design. I think if you were making a table with a similar look, but without all of those extras, none of what you see on the underside would apply. Simple edge joining with apron and legs is all you would need.

View Steve's profile

Steve

2774 posts in 2076 days


#6 posted 05-26-2022 02:13 PM



Could be to relieve tension in the slab to keep it flat.

- corelz125

this is most likely the reason for the cuts. It’s a way to help get the slab flatter without having to lose too much thickness.

View SMP's profile

SMP

5392 posts in 1399 days


#7 posted 05-26-2022 03:50 PM



Could be to relieve tension in the slab to keep it flat.

- corelz125

Yeah i am guessing it was cupped, can probably tell by looking at the endgrain direction of the glue up. And they were allowing a relief for when they clamped it down.

I have seen old Japanese master craftsman do this on beams, to give control of where the cracks go, kind of like expansion joints in concrete.

View Lazyman's profile

Lazyman

9779 posts in 2881 days


#8 posted 05-26-2022 04:29 PM


The metal is a U-profile, bit the cuts I’m talking about are perpendicular to the iron U-profile.

It’s interesting as, based on the rest of the construction, those who buildt this table knew what they we’re doing, so I’ll expect they had something they beleived had a purpose.

- TEK73

Ah, I see. I thought those were just joints between the boards. I agree that those are probably relief cuts to help flatten the panel. I suppose it could have been preventative to prevent future warping but they are not normally necessary if the panel is pretty flat and the proper moisture content to start with.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Madmark2's profile

Madmark2

3485 posts in 2082 days


#9 posted 05-26-2022 07:33 PM

One trick for a tight seam is to slightly undercut or bevel the edges slightly. This allows the wood to expand into the gap with minimal effect on the top. Each board is attached with a single screw, allowing it to move either side. To prevent buckling, the edges are undercut to reduce the contact area, and proportionately, the buckling forces.

PS. If you edit and resave your pictures, they’ll come out right side up when uploaded here.

-- The hump with the stump and the pump!

View Aj2's profile

Aj2

4492 posts in 3292 days


#10 posted 05-26-2022 10:16 PM

Too me all the metal and relief cuts on the underside of a table shows a lack of confidence of the craftsman.
Building furniture that way removes the hope that someday when the table isn’t needed anymore it cannot be reclaimed. The boards are all butchered up with cross cuts.
Might as well throw it out with lkea or living spaces tables.
Tables don’t need to be perfectly flat to serve their purpose. I find a table a little wonky from time and use far appealing.
Good Luck

-- Aj

View TEK73's profile

TEK73

411 posts in 1201 days


#11 posted 05-27-2022 10:15 AM



Too me all the metal and relief cuts on the underside of a table shows a lack of confidence of the craftsman.
Building furniture that way removes the hope that someday when the table isn’t needed anymore it cannot be reclaimed. The boards are all butchered up with cross cuts.
Might as well throw it out with lkea or living spaces tables.
Tables don’t need to be perfectly flat to serve their purpose. I find a table a little wonky from time and use far appealing.
Good Luck

- Aj2

Hmm, that was actually a perspective on the topic I did not have myself. Reusing the material of this table will probably not be very easy – I agree on that.
You may refurbish/fix up the top down 2cm before you meet the relife cuts, so I’m not sure I would place it in the same category as tables made with 0.5 to 2mm laminated surfaces ;-)

Breadboard ends is the old timers way to go, I do however not like the look of those and for myself I would prefer a metal support to ensure that the table stays resonnable straight.

In this case it is obvious a selected method of building the table, as it is done on both main table plates as well as both inlay plates.
I’m quite sure the table is quite a number of years old (5-15?), it has a very nice feeling of real wood, and it is very nice and flat. Not sure that a straight would show, but by eye it seems perfectly flat.

-- It’s good to have an end to journey toward; but it is the journey that matters, in the end. - Ursula K. LeGuin

View Tony1212's profile

Tony1212

709 posts in 3228 days


#12 posted 05-31-2022 01:52 PM



One trick for a tight seam is to slightly undercut or bevel the edges slightly. This allows the wood to expand into the gap with minimal effect on the top. Each board is attached with a single screw, allowing it to move either side. To prevent buckling, the edges are undercut to reduce the contact area, and proportionately, the buckling forces.

PS. If you edit and resave your pictures, they ll come out right side up when uploaded here.

- Madmark2

This would be my guess. But if you look at the ends of the boards just below the metal caul in the second picture, the relief cuts end and the boards are tightly joined, probably to make it look better on the ends.

-- Tony, SW Chicago Suburbs

View 1thumb's profile

1thumb

725 posts in 3650 days


#13 posted 05-31-2022 01:59 PM

https://atlanta.craigslist.org/nat/tls/d/winder-router-sled/7489681883.html

-- WAR IS PEACE. FREEDOM IS SLAVERY. IGNORANCE IS STRENGTH --

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