Trestle style base for 4x12 Doug Fir boards...

[Michael Dunn]

Hey guys!

Do you think this base design will be strong enough to hold 3 4x12 DF boards? I am planning to drill three 1/2" holes through the width of each board to hold them together. I'll insert 1/2" threaded rod through each hole and use washers and nuts to hold them together.

What do you think? I personally think it will be just fine. I have no scientific way to back that up. I've seen similar sized tables with only two supports. I'm wondering if this table should have a center support? My client would prefer to NOT have one if at all possible.

[Dave Richards]

Hi Michael.

That table looks like it would hold a small car even without a center leg. I'd leave it out. The benches might be better with the center leg, though. I'd be inclined to add a cleat under the bench seats midway between legs. It'll do a lot to stiffen the seat.

Thanks for your comment in the other thread, too.

[Mike Wilkins]

Ditto on Dave's comment. Leave out the center leg on the table. The benches are a different story. Get a couple or 3 'stout folks' on the bench, and the joinery will be tested greatly. Fine design. I have some 2" thick DF myself and you just gave me a great idea. Thanks.

[Brian Tymchak]

Your project essentially sounds like a heavy workbench. My workbench tops (split top design) are each 3.5" x 12" x 90" (Ash). The leg assemblies allow for about 13" overhang on either end. Sagulator calculated that there would be essentially 0" deflection per foot in this top with a large weight (500 lbs) center-oriented.

Your top is essentially 4x36 with unknown span between the legs. I played around with sagulator for your table. You could have a 165" (13' 9") span between the legs with a 1000 lb weight in the center of the table and still be "acceptable" according to Sagulator's standards with 0.02" sag per foot, 0.27" sag overall. You could have a party with the people dancing on the tables and still not need the center support...

[Michael Dunn]

Your project essentially sounds like a heavy workbench. My workbench tops (split top design) are each 3.5" x 12" x 90" (Ash). The leg assemblies allow for about 13" overhang on either end. Sagulator calculated that there would be essentially 0" deflection per foot in this top with a large weight (500 lbs) center-oriented. Your top is essentially 4x36 with unknown span between the legs. I played around with sagulator for your table. You could have a 165" (13' 9") span between the legs with a 1000 lb weight in the center of the table and still be "acceptable" according to Sagulator's standards with 0.02" sag per foot, 0.27" sag overall. You could have a party with the people dancing on the tables and still not need the center support...

Your project essentially sounds like a heavy workbench. My workbench tops (split top design) are each 3.5" x 12" x 90" (Ash). The leg assemblies allow for about 13" overhang on either end. Sagulator calculated that there would be essentially 0" deflection per foot in this top with a large weight (500 lbs) center-oriented. Your top is essentially 4x36 with unknown span between the legs. I played around with sagulator for your table. You could have a 165" (13' 9") span between the legs with a 1000 lb weight in the center of the table and still be "acceptable" according to Sagulator's standards with 0.02" sag per foot, 0.27" sag overall. You could have a party with the people dancing on the tables and still not need the center support...

Awesome! I keep forgetting to use the sagulator. I've heard a LOT about it. Thanx for crunching the numbers. In the third image you can see that the outside of the two supports are 79-1/2" apart.

[Von Bickley]

It looks like you have the center stretcher sitting on the floor. I would be concerned with that causing a problem.

[Michael Dunn]

It looks like you have the center stretcher sitting on the floor. I would be concerned with that causing a problem.

Nope. Take a closer look. I cut a 3/8" relief on the bottom of each leg to create 'feet'. I also cut the center stretcher to not be resting on the floor. I knew this would otherwise be a problem as the table could wobble on a floor that is not dead flat.

[Brian Tymchak]

Awesome! I keep forgetting to use the sagulator. I've heard a LOT about it. Thanx for crunching the numbers. In the third image you can see that the outside of the two supports are 79-1/2" apart.

Ah. Missed the dimensions in that pic. Didn't look at 'em enlarged. So your span is about 71.5" assuming 4" material in the legs. Sagulator says 0.004" deflection per foot. ..Think you're good to go...

[Michael Dunn]

Ah. Missed the dimensions in that pic. Didn't look at 'em enlarged. So your span is about 71.5" assuming 4" material in the legs. Sagulator says 0.004" deflection per foot. ..Think you're good to go...

Nice! Except now that I told my client this he wants to see if we can put the legs right at the ends of the table top. I placed the legs of the table in (I think) 13" from each end. Then the bench legs, which are only 2" from each end, can fit around the table legs.

[Brian Tymchak]

Nice! Except now that I told my client this he wants to see if we can put the legs right at the ends of the table top. I placed the legs of the table in (I think) 13" from each end. Then the bench legs, which are only 2" from each end, can fit around the table legs.

Well, certainly no problem structurally. Personally, I think it'll look funny and certainly no one will be sitting at the ends of the table. But, those are my personal biases coming in. Whatever the client wants to pay for..

FWIW, I might recommend a bevel or round over on the bottom edge of the top to be a little more "sitter-friendly". Not only removing a sharp edge but a potential splinter issue.

[Michael Dunn]

Well, certainly no problem structurally. Personally, I think it'll look funny and certainly no one will be sitting at the ends of the table. But, those are my personal biases coming in. Whatever the client wants to pay for.. FWIW, I might recommend a bevel or round over on the bottom edge of the top to be a little more "sitter-friendly". Not only removing a sharp edge but a potential splinter issue.

I agree. He doesn't want people at the ends of the table. I just told him I'd have to buy some more 4x4s if we changed this. He said forget about it. Moving forward as planned.

[Pat Barry]

I don't think that supporting the top will be an issue. I think the whole thing will rack laterally very easily, especially after its been used a year and probably pushed around a bit. I think you need supports to prevent racking.

[Tom Scott]

The whole table design looks good to me, and agree with the others that no center support is needed. The only thing I would rethink is the threaded rods through the top. His will not allow the wood to expand and contract and could cause issues down the road. Any reason not to just glue up the top? You got plenty of glue surface.

[Michael Dunn]

How's about this?

[Pat Barry]

I think that would be a very good addition to prevent the racking problem I mentioned. The location you have chosen looks good also.