Benchtop Question-Glued vs. Bolted

[Noah Barfield]

Hi all,

I'm a beginning woodworker and am in the planning phase of building my first workbench. Currently I'm looking at two plans:

http://www.popularwoodworking.com/projects/175_workbench

and

http://www.popularmechanics.com/home/how-to-plans/woodworking/4219723

The first one calls for gluing up the wood to assemble the bench top. The second calls for bolting it all together.

Is one method better than the other? What are the advantages / disadvantages of each?

Thanks,

Noah

[Kent A Bathurst]

Noah -

Wood expands + contracts in width and thickness with changes in seasonal humidity. The length is not affected. Some woods expand more and some less. This expansion is generally refered to as a % - ie, the wood will expand X% with changes in the relative humidity [actually, the moisture content of the wood, which is driven by the RH]. On a narrow strip of wood, that X% translates into minute dimensional change. But on something big like a wide benchtop, that same X% becomes non-trivial.

Because of this, I think you want to go with the glue. With the through-bolts, as the wood expands, it will be pushing against those bolts and will likely warp in strange ways. And - the wood WILL expand - you CANNOT overpower this - while the bolts won't lengthen.

Then - you have to have a construction method that takes all of this into account. You will need to plan on the benchtop expanding and contracting, while the base/frame will not [see: "length is not affected" above]. Without reading the PWW article, I've gotta believe they have all of this taken into account in their design.

For some detailed info on this: http://woodbin.com/calcs/shrinkulator.htm

This lets you select the species, enter the dimension [width of the benchtop in this case], and identify the RH range in your area. As an example, for Pine, loblolly [a predominant component of SYP in these here parts of the SE], using RH [not the MC] range of 50% - 70%, and a 30" wide top, the top will expand by 0.32" - that is 5/16" :eek: :eek:

The wood can't expand along the length of the bolts, but it will expand, so "waves" or warpage in the surface is the only place for that expansion to go. You wont' have a flat surface for long......

Rumor has it that someone's very first project years ago was a 30" benchtop out of red oak, they glued + doweled it PLUS put through-bolts - thinking "that'll keep this sucker together". That red oak supposedly just laughed at the bolts, and the whole thing curved - bending the bolts. Now, I don't know if this actually happened or not, but I tend to believe it because my red oak bench sure looks like that son-of-a-gun ripped his apart, and glued it back up with plugs filling the previous bolt holes :D :D

[John Sanford]

Hi all,

I'm a beginning woodworker and am in the planning phase of building my first workbench. Currently I'm looking at two plans:

http://www.popularwoodworking.com/projects/175_workbench

and

http://www.popularmechanics.com/home/how-to-plans/woodworking/4219723

The first one calls for gluing up the wood to assemble the bench top. The second calls for bolting it all together.

Is one method better than the other? What are the advantages / disadvantages of each?

Thanks,

Noah

Go with the Popular Woodworking. 'Tis a proper woodworking bench, rather than a skinny general purpose bench.

[John French]

Noah -

Wood expands + contracts in width and thickness with changes in seasonal humidity. The length is not affected. Some woods expand more and some less. This expansion is generally refered to as a % - ie, the wood will expand X% with changes in the relative humidity [actually, the moisture content of the wood, which is driven by the RH]. On a narrow strip of wood, that X% translates into minute dimensional change. But on something big like a wide benchtop, that same X% becomes non-trivial.

Because of this, I think you want to go with the glue. With the through-bolts, as the wood expands, it will be pushing against those bolts and will likely warp in strange ways. And - the wood WILL expand - you CANNOT overpower this - while the bolts won't lengthen.

Then - you have to have a construction method that takes all of this into account. You will need to plan on the benchtop expanding and contracting, while the base/frame will not [see: "length is not affected" above]. Without reading the PWW article, I've gotta believe they have all of this taken into account in their design.

For some detailed info on this: http://woodbin.com/calcs/shrinkulator.htm

This lets you select the species, enter the dimension [width of the benchtop in this case], and identify the RH range in your area. As an example, for Pine, loblolly [a predominant component of SYP in these here parts of the SE], using RH [not the MC] range of 50% - 70%, and a 30" wide top, the top will expand by 0.32" - that is 5/16" :eek: :eek:

The wood can't expand along the length of the bolts, but it will expand, so "waves" or warpage in the surface is the only place for that expansion to go. You wont' have a flat surface for long......

Rumor has it that someone's very first project years ago was a 30" benchtop out of red oak, they glued + doweled it PLUS put through-bolts - thinking "that'll keep this sucker together". That red oak supposedly just laughed at the bolts, and the whole thing curved - bending the bolts. Now, I don't know if this actually happened or not, but I tend to believe it because my red oak bench sure looks like that son-of-a-gun ripped his apart, and glued it back up with plugs filling the previous bolt holes :D :D


Sounds like you speak from experience....Thanks

[Noah Barfield]

Thanks guys! Ken, I was tempted to combine the two techniques. Thank you for saving me from hours of frustration! I'm thinking that the Popular Woodworking bench is the plan I'm leaning towards. There's a couple more plans in Woodsmith Magazine that I want to check out first.

[Kent A Bathurst]

There's a jillion plans out there. Before I ripped that first sucker apart, I flipped through a bunch of plans and books at my local wood/machinery store, picked 2 - 3 that seemed to be what I had in mind, read them in detail, and grabbed design pieces from all of them, and tossed in a couple ideas of my own. It's done very well for me for many years - there's a couple things I'd do differently, but not nearly big enough of a deal for me to spend time making another bench - got other stuff to do.

You'll enjoy it - plus, its a great opportunity to try out stuff you might not be quite sure how to do - it ain't going in the living room, after all. Plus, if it gets realy fouled up, just follow my lead and rip it apart............