support needed for long workbench top?

[Ken Platt]

Folks -

I'm trying to decide on a base design for a new workbench. The top is laminated maple, 96" x 30" x 2 1/4" thick. I'm leaning towards a trestle-type base, but am wondering if this means I would have to have an apron along the length of the top to give it rigidity along the 8 foot length. I realize that this is a pretty strong slab, but if I leave the overhang at the ends at, say 12", that leaves 6' of top with no lengthwise support, which seems like a recipe for bowing.

On the other hand, amongst the bunch of plans and books I have spread out in front of me is a Wood plan with a 72" x 36" top, trestle base with 4' between the trestles and no apron. Thoughts?

Thanks -

Ken

[dan sherman]

you will be fine.

I ran the following numbers through the sag calculator:
http://www.woodbin.com/calcs/sagulator.htm

Material: sugar maple
load: 1000 lbs
distribution: center load
span: 72"
depth: 30"
thickness: 2.75"

This yielded a maximum sag of .02"

Your never going to have 1000 lbs on top of your bench and even if you did it's not going to be a point load. If you spread the load out the sag drops to .01"

[Todd Burch]

A sag calculator... hummmmm...


Hey, Honey......

[Stephen Musial]

A sag calculator... hummmmm...


Hey, Honey......


Mrs Burch,

After you finish hiding the body, feel free to send me all his tools.

[Ken Platt]

Very cool tool. I sort of vaguely knew of the existence of it, but didn't even think of it for this.

Turns out Grizzly won't have the 2 1/4" thick benchtops in stock until august, so I ordered from a company called Global Industrial (the name sounds like something evil from a Bond movie). They didn't have a 96"length, so I ended up getting a 72" x 36" x 2 1/4"

If I'm using the sagulator correctly, I could put the trestle supports right at the ends of the table and it'd be fine unless I sat a grand piano on it, and maybe even then.

Many thanks - oh, and I want a cut of those tools if Todd's wife does him in. :) After all, it was my question....

Ken

[Chris Friesen]

I'm trying to decide on a base design for a new workbench. The top is laminated maple, 96" x 30" x 2 1/4" thick. I'm leaning towards a trestle-type base, but am wondering if this means I would have to have an apron along the length of the top to give it rigidity along the 8 foot length.

You'll be fine, although you'll probably want to do any heavy pounding (chopping mortices, for instance) directly over a leg. I would actually leave a 20" overhang for a 96" bench. (edit...for a 72" bench the equivalent overhang would be 15"). As described here

http://www.sawmillcreek.org/showthread.php?t=54658&page=2

this will give equal sag at both ends and in the middle.

[Todd Burch]

Y'all couldn't handle all the tools she would have to divvy out. :D