# Threaded rod through table top



## Lodewijk (Jan 17, 2017)

Hi there everyone,

I am new to this forum, and this is my first post.
I would like to ask some advise:

I am building a study desk. The top (and desk) will be made from Teak (actually a local species from Southern Africa, known as Kiaat). The top is 1.9m x 1.0m x 40mm (approx. 75" x 39" x 1.5"). The top is made up of 4 planks, each approximately 250mm (approx. 10") wide. What I have done is that I drilled 16mm (approx. 5/8") holes through the planks, and installed M12 (approx. 1/2") threaded rod across the width of the top. The threaded rods are therefore slightly shorter than 1.0m (39"). I glued the planks together, put the threaded rods through all 4 planks, put nuts and washers both sides, and tightened the nuts well. Afterwards I clamped the top, using bar clamps and cauls, and let it dry. The nuts and washers sit in a counter bored hole and I have plugged the hole, so the nuts are not visible / accessible. The top will then sit on a sub frame which is 20mm (approx. 4/3") thick. The sub frame will be flat, so not like an apron working about its strong axis. I am planning on bolting the top to the sub frame using M8 wood inserts, and slotted holes in the subframe.

I am wondering about the possible downsides in terms of durability, to what I have done. Does anybody have any experience with this sort of thing? What are the pros and cons?

I attach a few pictures to hopefuly give a better idea of what I've done.


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## HerbC (Jul 28, 2010)

The wood is going to "move" across the width of the panel due to seasonal changes in environmental humidity. If it shrinks it probably won't cause much of an issue. If it tries to expand you will probably see damage eventually.

Good luck!

Herb


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## papadan (Mar 6, 2009)

Your threaded rods serve no purpose except to restrict wood expansion. I would remove them and reseal the holes on the edges.


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## johnstoneb (Jun 14, 2012)

I would just leave them in there. I have seen bench tops bolted together this way and no problems after many years.


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## wuddoc (Mar 21, 2008)

My coffee table workbench top is secured with all-thread similar to what you are doing and has stayed together for over 20 years.

The old maple top woodworking labs benches you use to find in schools years ago used all-thread to secure the top pieces together. I discovered this when I wanted to convert a 4 student place with vices 5' x 5' bench top to a 2 vice 3' x 5' bench.


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## Lodewijk (Jan 17, 2017)

Thank you for the replies so far.

It seems I have two votes "Good" and two "Bad"... I might have a 50 : 50 chance of it being ok. I will finish the top all round with three or four coats polyurethane, the short ends with seven or eight, and hope for the best.


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## shipwright (Sep 27, 2010)

You are fine. Solid wooden rudders have been made this way for centuries and then immersed in seawater.
You won't be seeing any problems from wood expansion.


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## TObenhuber (Jan 15, 2014)

I'll start with welcome to LJ. Its a great community.

Second, I haven't tried this method before but it seems like it could look awesome with the bolts showings. Depends on the customer and what they plan to do with it.

If you are still worried about the wood movement, I suggest try it. If it falls apart, it will not be tomorrow. Probably won't even be this year or it a few years. I have done several laminated tops that are pocket holed through the mounting surface. All are still intact and have been moved across the US a few times. None of them are showing signs of falling apart. I think you have the dimensions working for you, the 1.5" thickness (what I generally use as well) is very strong. Will your table last through the centuries, none of us will know.

Have to keep that in perspective.

Here are examples I have made with laminated top. Nothing but glue. Held down by pocket screws from the base. Maybe it won't last for a thousand years but my wife loves them. In my book, that's what's important.
http://lumberjocks.com/projects/178594
http://lumberjocks.com/projects/101403


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## TObenhuber (Jan 15, 2014)

Another though, if you want to prevent some expansion problems. Maybe drill the holes in the base over sized and the holes in the bottom of the top with pilot holes. Use some washers for the screws/bolts. The washers will allow the screws to clamp the base to the top but the over sized hole should allow the top to move with out causing issues with constriction from the base. Just an idea.


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## Nubsnstubs (Aug 30, 2013)

I don't know about the Teak you are using, but in general, Indian or Asian Teak is supposed to be the most stable wood there is. More than likely, not an issue. ............ Jerry (in Tucson)


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## AlaskaGuy (Jan 29, 2012)

> My coffee table workbench top is secured with all-thread similar to what you are doing and has stayed together for over 20 years.
> 
> The old maple top woodworking labs benches you use to find in schools years ago used all-thread to secure the top pieces together. I discovered this when I wanted to convert a 4 student place with vices 5 x 5 bench top to a 2 vice 3 x 5 bench.
> 
> - wuddoc


Yes, our schools here have many old work tables build like that.


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## Lodewijk (Jan 17, 2017)

> Another though, if you want to prevent some expansion problems. Maybe drill the holes in the base over sized and the holes in the bottom of the top with pilot holes. Use some washers for the screws/bolts. The washers will allow the screws to clamp the base to the top but the over sized hole should allow the top to move with out causing issues with constriction from the base. Just an idea.
> 
> - TObenhuber


Thanks for the suggestion, I am definitely going to allow for some movement with oversized holes or slots.


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## Lodewijk (Jan 17, 2017)

> I don t know about the Teak you are using, but in general, Indian or Asian Teak is supposed to be the most stable wood there is. More than likely, not an issue. ............ Jerry (in Tucson)
> 
> - Nubsnstubs


Hi there. You got me interested in learning a bit more about the Teak I'm using. Its not in fact the same as Indian Teak, but called African Teak. Interestingly it also resists movement due to moisture, which is probably why they called it Teak. Some other very interesting properties, such as the magical medicinal properties of the red sap 

African Teak, with magical healing red sap

Indian / Asian Teak


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## johnstoneb (Jun 14, 2012)

Kiaat, muninga, narra are all names for your wood. It is closely related to Padauk. pterocarpus. It is softer than African paduak and does resemble teak and maybe a substitute for teak in that it is used in shipbuilding


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