LumberJocks

Bench length without sagging

  • Advertise with us

« back to Designing Woodworking Projects forum

Forum topic by Manitario posted 564 days ago 1448 views 0 times favorited 9 replies Add to Favorites Watch
View Manitario's profile

Manitario

2260 posts in 1482 days


564 days ago

Hey all, I’m building a bench out of a slab of elm to compliment a elm slab trestle table I’ve made for the dining room. The slab is ~2 1/2” thick and about 75” long. I’m just curious if it would be strong enough to support 4 people without bowing in the middle or if I’ll have to design some sort of support for the middle of the span. In general, is there any sort of guidelines/calculator as to how long you can make a bench span before the weight of people sitting on it will bow it?
thanks!

-- Sometimes the creative process requires foul language. -- Charles Neil


9 replies so far

View Dusty56's profile

Dusty56

11638 posts in 2287 days


#1 posted 564 days ago

How far in from the ends do you plan on placing the legs ?
If they’re going to be at the very ends , I would put a support in the middle just to ease the stress on the ends and for stability. JMO : )

-- I'm absolutely positive that I couldn't be more uncertain!

View Manitario's profile

Manitario

2260 posts in 1482 days


#2 posted 564 days ago

I was planning on putting the legs within about 6” of the ends…also considering making two shorter benches instead of one long bench…

-- Sometimes the creative process requires foul language. -- Charles Neil

View Dusty56's profile

Dusty56

11638 posts in 2287 days


#3 posted 564 days ago

I think the two benches would be better in the long run : )

-- I'm absolutely positive that I couldn't be more uncertain!

View DKV's profile

DKV

3059 posts in 1103 days


#4 posted 564 days ago

Rob, try the below. It’s for shelves but aren’t benches nothing more than shelves for people? Lot’s of people use the sagulator. 2 or 3 inch edges run along the length of the bench also help with load.

http://www.woodbin.com/calcs/sagulator.htm

-- 2014 will be a different year...at least for me it will.

View Manitario's profile

Manitario

2260 posts in 1482 days


#5 posted 564 days ago

you’re probably right…just twice the amount of work!

-- Sometimes the creative process requires foul language. -- Charles Neil

View DKV's profile

DKV

3059 posts in 1103 days


#6 posted 564 days ago

More methods…

http://www.diyadvice.com/diy/built-ins/materials-and-hardware/sagless-spans/

-- 2014 will be a different year...at least for me it will.

View Dusty56's profile

Dusty56

11638 posts in 2287 days


#7 posted 564 days ago

I’m just thinking about creature comforts…say you have a couple of children and a couple of adults seated. The kids would need to sit closer to the table than the adults which might make for some uncomfortable dining : )

-- I'm absolutely positive that I couldn't be more uncertain!

View Manitario's profile

Manitario

2260 posts in 1482 days


#8 posted 564 days ago

Thanks DKV; that is exactly what I was looking for. Interestingly, the sag is quite a bit less than I expected, even with a presumed 200lb load/foot the sag in the center is only 0.1”. Dusty, your point is well taken though, a bench with 4 people on it is inconvenient at best, although rather convenient for me to make…

-- Sometimes the creative process requires foul language. -- Charles Neil

View Dusty56's profile

Dusty56

11638 posts in 2287 days


#9 posted 564 days ago

What’s four more legs in the scheme of things ? LOL
I wasn’t really concerned with the sag factor as much as I was with the future enjoyment of your projects.

I used to have as my signature ; “Do what you want to do , you’re going to anyway” : )

-- I'm absolutely positive that I couldn't be more uncertain!

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase