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Using inserts to attach metal legs to large maple slab

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Forum topic by d85 posted 09-24-2018 12:40 AM 575 views 0 times favorited 10 replies Add to Favorites Watch
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d85

8 posts in 26 days


09-24-2018 12:40 AM

Topic tags/keywords: threaded inserts table legs wood slab

I’d like some input regarding using threaded inserts to attach legs to a maple live edge slab. I want to use an insert so the legs can be taken on and off if the table needs to be moved. The slab is roughly 6’ L x 29” W x 2.5” H.

All of the inserts I find don’t seem like they are long enough to prevent any movement.

Does anyone have experience attaching a large slab using these inserts? If so, what length were they and where can I find them. The only ones I’ve found for hardwood on amazon and other sites has been 3/8×0.50”.


10 replies so far

View mtnwalton's profile

mtnwalton

37 posts in 1172 days


#1 posted 09-24-2018 03:24 AM

I don’t think the threaded inserts would give enough strength. Have you considered hanger bolts? – wood threads on one end, machine threads on the other. I’m not sure how large they come, at least 3/8”
this is all assuming you don’t have a table apron.

View jbay's profile

jbay

2677 posts in 1045 days


#2 posted 09-24-2018 03:29 AM



I don t think the threaded inserts would give enough strength. Have you considered hanger bolts? – wood threads on one end, machine threads on the other. I m not sure how large they come, at least 3/8”
this is all assuming you don t have a table apron.

- mtnwalton

What does the machine thread screw into?

View msinc's profile

msinc

524 posts in 649 days


#3 posted 09-24-2018 06:14 AM

I have done this and here is how I did it…you cannot use the inserts directly into the wood of the table. It just isn’t strong enough that way, even in oak or hickory. What I do is to make a metal plate that acts as a “load spreader” and use metal inserts. The plate is ideally 3 or 4 times the size of the leg attachment, example, 3” post or leg would get a 9” plate. It can be smaller, but bigger is better in this case.
I attach it to the table with epoxy and screws. The inserts go into the metal plate and the legs attach to that. Depending on use and environment, the inserts might hold up directly in the wood, {grandma who lives alone??} But any rough use, kids, big dogs running around, farm animals in the house, husband and wife beating each other half to death, etc….all this will kill it. Load spreader plate can even be aluminum if it is thick enough. It’s not like you can see it anyway, but it will allow for the legs to be easily removed when needed.

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ChefHDAN

1133 posts in 2995 days


#4 posted 09-24-2018 11:29 AM

What sort of metal legs, and length? Depending on the weight of the table some legs just need to be held in place while others will get a lot of torque, especially with a heavy top

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

View d85's profile

d85

8 posts in 26 days


#5 posted 09-24-2018 12:47 PM

Thanks everyone. Apologies for not including pictures. I included them below.

msinc, Thanks for the explanation. Do you use one solid plate across the width of the table, or two separate. What thickness are you using. I would think half inch since most inserts are that in length. In my situation, I could attach 6 screws.

As you said, If this was going into a house where there isn’t much activity I wouldn’t put so much thought into that. I have two small rambunctious boys, and a hyper medium size dog.

On a different note: There is about a 20” split on one side. I’m going to put 3 bow tie inlays in it to stabilize it. What I have a question about is not how to secure the side to side expansion but the up and down warping. there is about 1/4 inch movement in that direction. I placed clamps on this to bring it together, but what would be the best way to secure this movement. The person I bought the slab from suggested pocket screws to stop the movement.

Thanks again to everyone for your input.




Link to the insert:
https://www.amazon.com/Z-Threaded-Insert-Internal-Threads/dp/B07F1NQSNN/ref=sr_1_7?ie=UTF8&qid=1537792534&sr=8-7&keywords=wood+threaded+insert

Link to the legs:
https://www.etsy.com/listing/571842379/economy-style-square-style-metal-table?ref=listing-shop-header-0

View diverlloyd's profile

diverlloyd

3113 posts in 2003 days


#6 posted 09-24-2018 12:58 PM


I don t think the threaded inserts would give enough strength. Have you considered hanger bolts? – wood threads on one end, machine threads on the other. I m not sure how large they come, at least 3/8”
this is all assuming you don t have a table apron.

- mtnwalton

What does the machine thread screw into?

- jbay

The wood thread side screws into the wood like a lagbolt and the machine thread side would stick out. Then you put the legs on the machine screws and tighten them down with regular nuts or go the extra step and use a fender washer and nylon lock nut.

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jbay

2677 posts in 1045 days


#7 posted 09-24-2018 01:14 PM

Oh, I see, the metal plate attaches to the bottom of the table.
I thought there was a square wood leg. (I should have read the title, duh)

View Lazyman's profile

Lazyman

2526 posts in 1533 days


#8 posted 09-24-2018 01:27 PM

D85, your Etsy link looks like your sales receipt, which we can’t see. Give us a link to the listing page or a better picture from the side, if the 3rd picture is the top for the leg.

Assuming the third pic is the top of the leg and it is intended to be attached with 6 bolts, I think that 6 threaded inserts would probably be strong enough. Of course 6, hanger bolts would probably be stronger and easier, You might need to shorten the machine thread end so it is just long enough for a nut to hold it on. Lag screws would work as well but just realize that attaching and reattaching the legs multiple times may weaken it over time. If that happens a couple of drops of CA thin can be used to reinforce the threads in the wood if they get loose (let the CA set before reinstalling the lag screw).

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

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d85

8 posts in 26 days


#9 posted 09-24-2018 01:31 PM

Thanks mtnwalton and diverlloyd, I think this would give the security of going into the wood a good 1 1/2” and the benefit of being able to remove the legs. I understood the suggestion earlier as wood screws with the hex nut head.

View diverlloyd's profile

diverlloyd

3113 posts in 2003 days


#10 posted 09-24-2018 03:43 PM

This is what they look like. Woodscrew with a hex head would be a lag bolt. A hanger bolt will need to have nuts to tighten it down.

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