Workbench Structural Anatomy

[bitingmidge]

During the course of the last year or so, I've read a lot of stuff, and heard a lot of opinions about what does or does not constitued a good workbench construction.

Taking a leaf from "MYTHBUSTERS" there are two myths of construction I'd like to try to dispel, but need the help of someone with a bit of engineering nouse!

MYTH 1: Heavier is better.

Wrong!!

A certain mass is necessary, but after a particular point, heavier serves no purpose, other than to put more load on joints and increase the probablility of racking. (From zero to not much if you get to Myth 2!). Once a structure is imovable it cannot be made more so. It needs to be strong enough to overcome the forces generated by your arms at full tilt, or maybe at worse, a medium hammer blow on the axis of the bench.

Any stronger or heavier, and you've just wasted material.

MYTH 2: A proper bench needs mechanical fasteners so that the joints can be tightened to prevent racking.

Wrong!!

This comes I think, historically when glues were not as reliable as today and mechanical fixings were used, and similarly when the bench needs to be dismantled for removal. When mechanical fastenings are used, the joints are subject to minute movement in the timber, which will allow similarly minute movement in the joints, and hence the need for periodic tightening of the bolt/screw fixing.

Using modern glues, it is very easy to incorporate an adhesive which will be stronger than the timber used, and combined with a reasonable mortice and tenon joint will result in a completely rigid connection, creating a "moment joint"in engineering parlance. Minor movement in the timber will not create joint failure, and the full bracing effect will be maintained.

If one was to create a reliable knock-down bench, it may be better to create the rigid joint, and cut the stretchers in half, connected with bolted plates for their length. (does that make sense?)

I think there is a bit of a parallel here with boat construction, where traditionally bolted and rivetted vessels were heavily built and the structure moves and creaks quite happily but every so often a seam will open and needs attention, while light timber structures and modern construction enable completely rigid, immovable structures.


The above is not a statement of fact (although it could well prove to be :rolleyes: but I'd love to have an argument if it's not!!!

Cheers,

P :D

[silentC]

Myth 1: Perhaps, although if the material is heavier, it is probably denser and therefore potentially stronger. If all other things were equal, it seems a heavier bench should be stronger but I can't prove it. A bench carved from solid stone would be very heavy indeed but probably overkill for most work.

Myth 2: I made a bench for my lathe with the same construction that I will ultimately use for a workbench. It uses no fastners and no glue. It is held together with wedged tenons, wedged dovetail tenons, sliding dovetails and bridle joints. It might possibly need some dowel pins through the bridles but I've found that they are tight enough to not work loose. If any of the wedged joints become loose, they are easily tightened up again with a bit of thumping. Having heavy construction helps here because it gives a bit of dead weight against which to thump.

[bitingmidge]

Myth 1: Perhaps, although if the material is heavier, it is probably denser and therefore potentially stronger.

Isn't this a case of if it doesn't break/bend/move it's strong enough??? What I am getting at is if a bench of (say) 200kg is completely imovable in all respects, then 210kg is a waste of 10 kg of timber (and so on.)


Myth 2:It uses no fastners and no glue. It is held together with wedged tenons, wedged dovetail tenons, sliding dovetails and bridle joints. It might possibly need some dowel pins through the bridles but I've found that they are tight enough to not work loose. If any of the wedged joints become loose, they are easily tightened up again with a bit of thumping.

Apart from the joy of making the joints, WHY? if you had used glue they would not come loose, no thumping required, and no eventual breakdown of the joint. (I presume you have built it to be dismantled for moving?? and therefore gluing won't help!).

It is the working of the joint that causes the long term rickets, so I am postulating (I must stop eating so much fruit) that dismantling should be done somewhere other than at the right angled joints, contrary to historical logical tradition!

Cheers,

P

[silentC]

I suppose there is a break-even point where extra weight yields no benefit. I think this would depend upon the individual using the bench. Have you seen that bloke who can pull a semitrailer plus prime mover? I bet he would need a VERY heavy bench. If he was a woodworker, which he probably isn't.

Whether extra weight would actually turn out to be detrimental to the strength of the joints is another issue and, like I said, I don't think it would be - but have no way of proving it.

I got the idea for the joinery from Scott Landis's workbench book. I thought it would be fun, yes, but I also believe that a strong joint is a strong joint and doesn't need any glue. If you rely upon the glue alone, then you are stuffed if it fails. I suppose you could make a wedged joint stronger and unlikely to work lose if you glued it. I was really just agreeing that you don't need mechanical fasteners to make a strong bench and adding that you don't need glue for that either.

I'm also too cheap to spend money on bolts and fancy glue. The whole thing is made from a tree, except for the 4 screws which hold the lathe in place.

[Dan]

Have you seen that bloke who can pull a semitrailer plus prime mover? I bet he would need a VERY heavy bench.

Depends on how blunt his plane/chisel is. :)

[Termite]

I don't know what the ideal weight for a workbench is, I suppose you'd have to ask Jenny Craig about that, but I do know that it has to be heavy enough to be "dead". By that I mean when you are pounding something or chiseling, with a suitable block to save the surface of course, you don't get any "boing", all the force is absorbed by the bench. I dont think weight is a factor in the structural integrity of the bench but it is certainly a factor in the boing in the bench.

As for how the bench is held together, thats up to the individual. If rubber bands work for you then go for it. :D

[Wood Borer]

Interesting Thread Midge.

I think work benches need to be immovable and stiff.

Imovable so when you are chiseling horizontally or handsawing you don't have to chase the bench around your shed. My bench is not bolted to the floor but has sufficient mass so it's intertia resists any horizontal forces.

The stiffness is so the bench doesn't flex even if it stays in the one place on the floor.

It turns out that the materials we use add mass to achieve the above two requirements. So a heavy bench is not necessarily a good bench unless it is immovable and stiff.

If a new super light material was discovered that achieved my two requiements, was soft enough not to damage sharp edges on tools or timber then I would probably consider using it for a workbench.

BTW, consideration should also be given to where the mass is located so the workbench is stable even when overhanging large heavy projects are attached to the bench. I suggest a fair bit of the weight being down low.

[silentC]

I dont think weight is a factor in the structural integrity of the bench but it is certainly a factor in the boing in the bench.
I have this mental picture of a bench that makes one of those Looney Tunes type 'boing' sounds when you hit it. My kid has a toy workbench that makes a noise like that.

[Termite]

I have this mental picture of a bench that makes one of those Looney Tunes type 'boing' sounds when you hit it. My kid has a toy workbench that makes a noise like that.
If that tickles your imagination then you should be around when I hit my finger. :eek: :D :D

[Slavo]

It is held together with wedged tenons, wedged dovetail tenons, sliding dovetails and bridle joints.
Any pics of the joinery Silent? I cant think how a wedged dovetail tenon would look like.

[silentC]

The ends of the mortice are cut on an angle, then one side of the tenon is cut on the same angle with the other side straight. The wedge locks the tenon in place. See attached pic. It's good for stretchers.

[Zed]

sitting on the fence :

the bench should suit its desired design purpose.

it should go "boing" if required, it should not move unless you want it too, if you move house a bit it should knowck down unless you are superman, another outside underpant wearing superhero or his homosexual sidekick.

with my work bench I wanted a nice long bench that was massy enough not to move but wasnt so hard to move if I decided to move it. therefore the drawers are removable as is the bench top. thus in a pinch I will whip out the drawers, unbolt the top from the stretchers and move the whole lot myself in 6 phases (4 x drawer, top then carcase). altogether I reckon the sucker weighs in at close to 200kg. What I like about the carcase is that the hardwood construction means its strong enough for me to lift it in the middle and as long as its balanced 9which it is) I can move it without anything breaking - albeit slowy - it is very heavy after all....

I havnt whacked it with anything yet so cant comment on the "boing-ability".

another thing since its so heavy I can use it as a stable table for my machinary (such as the 12' disc sander) and grinder.

I will finish it one day and post the last entry on the relevant thread - I promise!

[Wood Borer]

Sounds like a good idea Zed - the removable mass.

I once cleaned out the scraps from the shelf under my bench, I put them back immediately after the bench realised it could escape. I realised just how important the mass was even though I hadn't intentionally placed it there in the first place.

As far as bonking on your workbench, I wonder how many people would own up to such a seemingly interesting activity. :D

[bitingmidge]

I think work benches need to be immovable and stiff.

It turns out that the materials we use add mass to achieve the above two requirements.

If a new super light material was discovered that achieved my two requiements, was soft enough not to damage sharp edges on tools or timber then I would probably consider using it for a workbench.


Well the good news is that super light material has been discovered and it's actually been well tested: plywood.

Immovable is as easy to achieve as a couple of screws in the wall or floor. (Holes aren't that hard to repair when you move house). I have used the screw into the wall trick to stabliize the fumping bench, which is very stiff, but proportionally able to be toppled by me bending a bit of pipe in the vice.

Failing convincing anyone about the floor screws, fill the base with sandbags to your own specifications.

A plywood box frame with modern adhesives and minimal structure would give a very stiff structure. (Refer the tea-chest, which has semi flexible joints yet still remained in shape despite copping a pounding in transit).

The top would only need to be a torsion structure with maybe a 12mm upper skin, if stringers were also of 12mm and say 300 mm max in each direction, apart from the sound I doubt whether you'd feel the difference.

I have a feeling that the next round of responses is going to lead us back in a circle!

P :D

[silentC]

Yes, it sounds like a light-weight bench for light-weights. Probably the type of person who would drink light beer and caffeine-free coffee. Nah, I'll take my thumping great solid b@stard of a bench any day :p

What is it with arty architect types that they want to make things that are stronger than they look? They seem to have this obsession with making people feel uneasy :rolleyes:

Yours in solidarity, brothers.

[Zed]

My bench doesnt bolt to the wall, its a free standing jobbie.

my (what are the called??) black and decker workmate clone and another bench thing made from treated pine and particle boad with a melamine top both have a lower deck with a 40kg "off" cement bag to give them stability, whacking for the purposes of...

[LineLefty]

Hmm yes, I work with engineers whov'e advised me that the job of an engineer is to take the architects design. Remove as much steel and concrete from it until you're just above safety margins. The two Narrows Bridges in Perth look identical, the new one has about 30% less mass than the original. IT's true my workmatesm uni mates ex-girlfriends dad worked on it.

[IanW]

with my work bench I wanted a nice long bench that was massy enough not to move but wasnt so hard to move if I decided to move it.....

Yeah Zed - and remember General Debility when you're designing benches to be moved! ;)

I've mentioned elsewhere how a 'portable' bench I built from some wood of the ubiquitous Skipwood tree, convinced me that portability was a diminishing thing. :o The replacement has about 2/3rds the weight in the top (not sure, exactly, but less than 50kg) with another say, 20 kg max in the undercarriage. The approx 2 inch thick centre of the top is plenty stiff enough (I'm pretty sure it's Spotted Gum, actually) and the weight is adequate for most jobs, with the feet sitting on concrete. If it started to wander under heavy planing, I'd know it's time to get the oilstones out!

All of the benches I've built in the last 20 yrs or so have traditional wood joints (dovetails and M&T) in most places, but I'm guilty of using a few bolts. These are for the stretchers (for easy knockdown) and on the end caps. Frankly, I can't see how I could hold the end cap that carries the 'nut' for the tail vise (which is entirely wood, including the screw, of course!) by any 'pure' wood method, since the tapped end is buried in the vise, but there may be some elegant solution that escapes me.

For stretchers, I have tried 'tusked tenons' as an all-wood solution, but they are a bit of a pain (literally) because you need to have several inches of tenon sticking through to take the tapered slot for the tusk. Eight by 1/2" bolts with the heads countersunk into the legs don't bark shins. Hadn't thought about Silent's wedged d'tail - a perfect solution. The last and final, definitely ultimate, bench which is sort of under construction (still mostly in my head) will probably use them!

But it won't be finished any time soon. I just completed a couple of projects on the weekend that were on the go for several years each, and it will take me quite a while to recover from that!
Cheers,

[bitingmidge]

What is it with arty architect types that they want to make things that are stronger than they look? They seem to have this obsession with making people feel uneasy :rolleyes:

I could quote an entire passage from "The Princess Bride" right now, but I'll save it for later, just don't quibble when art is involved OK?

I think the world's best example of that is the glass floor in Auckland's skytower observatory. 100 floors or something in the air, and you are standing on a glass floor looking at the street.

Enough to give you a couple of lumps in the throat if I do say so m'self!

P

:D

[IanW]

Enough to give you a couple of lumps in the throat if I do say so m'self!
:D

And a couple of lumps somewhere else, if you slip on the bleedin' thing...... :D

[Harry72]

I suppose there is a break-even point where extra weight yields no benefit. I think this would depend upon the individual using the bench. Have you seen that bloke who can pull a semitrailer plus prime mover? I bet he would need a VERY heavy bench. If he was a woodworker, which he probably isn't. I was wondering why my bench walks around while Im using my hand plane, last year before I had my operation I was a gym yuppie of 4yrs... on the leg press I was pushing 4 sets of 10 reps at 360kgs, guess I should leave my legs out of it while planing!

[Gumby]

I think the world's best example of that is the glass floor in Auckland's skytower observatory. 100 floors or something in the air, and you are standing on a glass floor looking at the street.


:D

Yeah I agree about that floor. That is scary , and so is leaning back against those windows in that tower that slope away from you. I couldn't do it myself..........I'm a chicken when it coes to heights. :D

[Wood Borer]

When I was at Uni one of the subjects we studied was Mechanical Engineering we studied beam theory including deflection of beams under loads etc.

My parents are farmers and I lived on the farm until I came down to the big smoke to go to Uni. On the farm to take a tractor and harvester or a truck across a creek, the farmers would cut down a couple of trees that “looked” strong enough and use them to make a bridge. They never seemed to break!

If you were to ask the farmers what the mass of the vehicles was, they would probably estimate them “she’d be a few ton”. Try and ask them how they knew the logs would be strong enough, and they would tell you they looked OK for a few ton.

Back at Uni, the calculations involved were horrendous to design a bridge using tapered beams to safely carry a moving load where the forces on the bridge were not evenly distributed, and where the load was not balanced from one side to the other. The farmers got away with it though.

Were these bridges on the verge of failing or were they able to withstand loads 10 or 20 times that of the tractor and harvester?

Looking strong enough is a bit of a hit and miss affair and quite dangerous although I was never aware of failures. Perhaps it is an evolutionary thing where those that muck up the estimations die and do not pass on the bad estimation genes.

I understand what Midge is saying and perhaps the cleverly designed ply bench with a torsion top might be stronger and more rigid than the bench with thick members. My personal preference would be for the thick timber model – this is an emotional preference rather than a decision based and engineering.

[bitingmidge]

Back at Uni, the calculations involved were horrendous to design a bridge using tapered beams to safely carry a moving load where the forces on the bridge were not evenly distributed, and where the load was not balanced from one side to the other. The farmers got away with it though.

Ahh yes, Rule 9 of the Ninja Code of Conduct:

"What you don't know, can't hurt you!"

P
:D :D :D

[Richardwoodhead]

Just to throw a spanner in the works. I made a couple of wood benches (solid, immovable), then had my local metaland welding mate weld a very strong frame out of 50mm hollow steel. About 2m by 1.2m. With upper and lower rails and cross supports, so I could have 2 surfaces (top bench and under-bench). AND attached heavy duty solid rubber wheels (the ones that move freely in all directions) onto metal flat plate at the base of my verticals.

I then tech screwed 150mm x 50mm jarrah sides onto the top metal frame. Put on a 18mm ply top and 18mm ply onto my under-bench. Then put a 3mm MDF cover sheet on top of the ply. Then attached 2 dawn clamps to one side of my jarrah bordered top frame.

This welded frame is very strong, but quite light. I can move the workbench-on-wheels freely around my workshop. Or keep it easily in one place by putting a stop under one or two wheels. After working with this lighter weight movable bench, I'd never go back to the old heavy fixed clunkers.

There's pleasure for some in constructing their wooden "dream" workbench. But if you're chasing strength, utility, economy (welded metal versus the cost & time of timber construction) and functionality - think about a steel frame on wheels. I've generated a number of converts around here.

I've since taken my old immovables, cut the legs shorter and bolted on wheels. Converting one to a movable router table and the other a movable docking table.Once you've experienced mobility, you won't go back...

[silentC]

I suppose it depends on what you want from a bench. I'd certainly prefer a timber bench to a steel one for aesthetic reasons. I also want one that wont move. If it had wheels, I'd want to be able to have all four of them off the ground when it was stationary. I've seen a couple of benches with fold down legs that permit this.

I guess people keep coming back to these old timber benches for a reason. Steel has been around for a long time and yet people still prefer to use timber construction. I suppose that could be largely because we are woodworkers, not metalworkers.

The steel benches I have used have always had a certain amount of bounce in them. That would be due to the sections used to make them but if you start going for square or rectangular sections over angle, you are adding weight and cost to the equation. Even midway between the legs, my bench is solid as a rock.

I can see how it might be handy to be able to move a bench around if you have limited space. I hardly ever move my bench and my workshop is very small.

It's horses for courses.

[bitingmidge]

Come to think of it, for all those years while growing up our family moved regularly (three years in one spot was a long time - but they never caught us! :D ) my old man had a bench frame made from 2" angle iron with bolted connections, so he could take it apart and move it.

It had three two inch hardwood joists as a top and used to take a fair old pummelling.

It didn't appeal to me I must say, but there is no doubt that it worked well.

Cheers,

P :D

[IanW]

I second Silent on just about every point.

Some folks are influenced more by what the bench looks like, some by what it has to do for them. I reckon I'm in the middle. I can't see any alternative to a wooden benchtop for my style of woodworking, which involves a lot of hand-held tools (both the ones that run on electrons and the ones wot run on sweat). It would be hard to imagine how to organise a tail vise and dog set in a mostly metal rig, and this is the part I use for at least 80% of my bench time. Also, I'd much rather have my edge tools scattered over a wooden surface, thanks - I hate having to take out nicks! The undercarriage could just as well be metal as wood, I suppose, but the aesthetics would bother me a bit.

To echo Silent - horses for courses....
Cheers,

[Richardwoodhead]

Agree with IanW and SilentC. I enjoyed the heck out of making my wooden work benches. And I've seen some wooden benches that are pieces of fine furniture. Just thought I'd mention the option. A steel frame is quick to construct, light and very strong. Plus you can bolt/screw a wooden perimeter (I used 150 x 50 jarrah) around the top frame - to which you can attach vices etc - and put on a wood / ply top.

[Cliff Rogers]

....my old man had a bench frame made from 2" .....Splinters..... the old man's bench..... geeze I remember it well.... it got burnt down in a fire about 34 years ago but it was about 20' long, 2'6" wide & about 2" thick. It was built in about 1958 out of 3 planks of compressed 2" hardwood splinters soaked in some sort of black oil. :rolleyes:

It seemed like it was about 4' off the (dirt) floor 'cos I used to have to stand on a wooden softdrink crate to see over it.

The new one he made had a frame made of welded 2" pipe & the top is... 3 planks of compressed 2" hardwood splinters soaked in some sort of black oil.... some things never change...:)

No sheyet, I'm going out to see the olds at easter, I should take a photo of it.

[Different]

Have to say I am on the "Bigger is better " side of the arguement.
My next bench will be 100mm thick laminated Kwila 3000mm long & 1100mm wide on a Vic Ash frame all held together with tapered wedged through tennons with full width tail vice both ends and vices on both sides
Wooo Hoo !

Ross

[Cliff Rogers]

... next bench will be 100mm thick laminated Kwila 3000mm long & 1100mm wide on a Vic Ash frame ....
Hooooollllllleeee Sheyet!!! A diesel mechanic.
Struth Ruth.... what the F' are you building???? :eek:

Mine's made out of Kwila & it's half that size all round but it costs more than $300 for the timber.

[AlexS]

Hooooollllllleeee Sheyet!!! A diesel mechanic.
Struth Ruth.... what the F' are you building???? :eek:



Obviously...a f'ing big bench :eek:

[Exador]

Hmm yes, I work with engineers whov'e advised me that the job of an engineer is to take the architects design. Remove as much steel and concrete from it until you're just above safety margins. The two Narrows Bridges in Perth look identical, the new one has about 30% less mass than the original. IT's true my workmatesm uni mates ex-girlfriends dad worked on it.

Resurrection time. I worked on a Design and Construct submission for the new Narrows Bridge when I was in Perth. One of the big considerations was the effect of the new bridge's weight on the old one, as it was to be founded well within the zone of effect of the old one's footings and the soil is uniformly muck until a long way down. In the end the weight was reduced using high-strength concrete and post-stressing and the piers were founded way below the existing ones IIRC.

Another major consideration was the effect of the approaches on the existing approach embankment. Our proposal (which didn't get up) was to use polystyrene foam as the core material for the embankment, which is done in sucj places as Finland and Norway to allow roads to be built on permafrost, which would melt under the weight of a conventional road. There were to be 2 types of foam used, of different densities, which would be placed as blocks and tied down to soil anchors deep underground. This was to be covered with a couple of layers of impermeable, fuel-insoluble membrane and the lot covered with pavement. The sides of the embankment would have had a meter or so of topsoil (sand in this case). The overall embankment wold have had the same mass as the meter or so of soil(mostly marine clay) that would have been excavated for it to socket into and thus no net effect on the adjacent embankment. Construction was to be done in stages, excavating and replacing only a few square meters at a time. It was a really brilliant solution, but MRWA went with the traditional (and really expensive) approach of a pile-supported embankment, drilling hundreds of bored piles and driving hundreds of screw piles to help take the weight.

[MajorPanic]

MYTH 3: Having a working DC system (with REALLY snazzy pipe work) is better.

Wrong!!

Ask Midge. :rolleyes: :D :D :D

[Driver]

.... the farmers would cut down a couple of trees that “looked” strong enough and use them to make a bridge. They never seemed to break!

If you were to ask the farmers what the mass of the vehicles was, they would probably estimate them “she’d be a few ton”. Try and ask them how they knew the logs would be strong enough, and they would tell you they looked OK for a few ton.


Resurrection time 2:-

One of my favourite quotes:-

"Anyone can design a bridge that works. The trick is to design one that only just works."
Colin Chapman - Engineer (The bloke who founded Lotus Cars).

Of all the things that our engineering lecturers taught us (Oh, these many years ago, Virginia!) - that one quote from a really good engineer resonated loudest for me. He was a structural engineer, incidentally.

[BobL]

Hmm yes, I work with engineers whov'e advised me that the job of an engineer is to take the architects design. Remove as much steel and concrete from it until you're just above safety margins. The two Narrows Bridges in Perth look identical, . . . . . .

Errr . . . . . .No, not from underneath they don't.

Photo shows 360 panorama from underneath the two bridges. The lesser mass, younger one is pretty obvious.

BTW the fisherman in the photo is the guy who designed the Sydney Olympics torch up through the water thingo. He just happened to be standing there and asked him if would mind staying in the shot.

[greenie512]

I’m of the group that say, a bench is a tool to be used and abused so rather than build a fine bit of furniture my benches are pretty basic.
<o></o>
All butt jointed frame
Liquid nails – glue
Screwed joints<o></o>Yuk, I hear you say liquid nails but I used rough stud timbers (cheap as chips) so this acted as filler/glue. The whole thing was designed around sheets of seconds ply so tops are two skins of 18mm thick 700 mm wide and lower shelf 18 mm thick 500 wide. A 2.4 long bench took less than a morning to construct.
<o></o>
I regularly climb onto the bench for access to shelving above it and load it with 100 kg cabinets and so far this crude construction is as solid as a rock.
<o></o>
However a lesson I leaned was to be more careful when laminating the two boards to form the worktop, each end has a slight dip/bow – I could plane this out but so far it isn’t a big issue.

[Exador]

Resurrection time 2:-

One of my favourite quotes:-

"Anyone can design a bridge that works. The trick is to design one that only just works."
Colin Chapman - Engineer (The bloke who founded Lotus Cars).

Of all the things that our engineering lecturers taught us (Oh, these many years ago, Virginia!) - that one quote from a really good engineer resonated loudest for me. He was a structural engineer, incidentally.

The trick in engineering is always to get the most with the least. The bit that Chapman didn't say was that the point at which it has to "only just work" is when it's at the end of its life. Bridges are easy to build light if only they didn't have to last...

[jmk89]

The trick in engineering is always to get the most with the least. The bit that Chapman didn't say was that the point at which it has to "only just work" is when it's at the end of its life. Bridges are easy to build light if only they didn't have to last...
...and Chapman's racing cars were famous/notorious for mechanical failures when in the lead because he had miscalculated how much of the safety tolerance that every on else used that he could take away - often not because the particular part couldn't last the race, but because some other part put more strain on a part than had been realised.

[Shannon Nash]

Just thought I would give my 2 bobs worth about the 'boing' factor. A bench will boing due to it acting like a spring absorbing the energy (deflecting downwards) and then returning it and vibrating eg boing. A heavier bench thicker top will generally deflect less and not boing. It will be providing a better 'reaction force', it is generally stiffer and won't boing. So the initial comment about the heavy bench 'absorbing the energy' is not correct. It is because it returns the energy that it 'feels better' to work with.

The same as working directly above a leg of a bench when you cut mortices for example.

I work with an old metal frame desk that will be replaced in the near future with a solid tassie oak bench with about a 60mm top. When I get around to it.

Cheers
Shannon

[Rocker]

For some reason, I missed this thread when it was first posted, but I would like to put in a plea for bolted joinery for the stretchers of a workbench. I have used my workbench in Colorado and QLD for over ten years, and have never had to tighten the bolts - they never work loose. A picture of the stretcher joinery is given in this old post in another thread: http://www.woodworkforums.ubeaut.com.au/showthread.php?p=53170&highlight=workbench#post53170 .

The joint is dead easy to make and rock solid. The two blocks through which the bolts pass are glued and dowelled above and below the stretcher, which is just butted against the leg.

Rocker