Flattening a 2X4 Benchtop

[drkg]

Some help for a noob would be much appreciated here:

Three days off and I'm starting my first shop project. I'm builing two benches 60X27 that I will position together in a 'L' shape. The tops will be made of 18 2x4s face glued and screwed together. The tops will be banded by 1x6 that will sit 1/4" proud all the way around the top. The actual work surface will then be 1/4" thick hardboard. I don't want to attatch the hardboard so that I can remove and replace it as necessary. I've got a pretty good plan drawn up and am confident I have an accurate cut list that will allow me to work pretty efficiently. My question is this:

What is the best way to flatten the laminated 2x4 surface?

I speant over an hour selecting the 30 straightest 2x4s I could get, and am fairly happy with the ones I found. I need to the top to be as close to flat as possible so that the hardboard will lay down nicely without glue or screws to hold it.
My power tool options for flattening the top are:

1)TS (Craftsman BT) that I could use to rip a flat top edge on each of the planks.

2)Router table I could use to edge joint each plank before laminating

3)3 1/4" power planer I could either plan each board individually or plane the entire top once its complete.

To get the top near to flat I was going to assemble the boards face down on my garage floor, and I get to start with relatively flat 2x4s. In you alls' opinions, how flat does my top need to be to allow the HB to lay down, and with the tools I have available, what will be the most efficient way to flatten the top to an acceptable degree?

Thanks in advance.

[Curly Qsawn]

I'd vote for the power planer after assembly. You may want to consider using shellac or other finish to minimize warping once you get it flat. Hopefully, you've allowed the lumber to season a bit.

[Ken Weaver]

Another approach would be to edge joint each 2x4, turn the jointed edge down for the glue up and use cauls to hold them down. That would give you the closest match for a final sanding. Curly has a good point, check your moisture if you bought the 2x4s at a box store, especially if they are construction grade 2x4s. I use them a lot for my shop cabinets and fixtures and usually have to let them set for a while. You do know that you are headed for a jointer/planer decision don't you?

[Otter]

here is a link for you. I have not used this for benchtops but have used it for small tables and it works great, is low tech and you have all the tools needed.

http://www.highlandwoodworking.com/i...n=Custom&ID=58

[JR]

It sounds like you've got a pretty good plan. I might add one idea regarding the 1/4" top. I used the same principle on my benches, but found the top tended to curl up and warp. Some carpet tape would be a good idea to keep it down.

Having said that, I don't think the underlayment needs to be perfect. I've never used a power planer, so I can't comment on how effective that would be.

You do have a router, so I'd think a sled could be devised that would allow a router with straight bit to run accross the completed surface, planing it to a consistent finish.

JR

[backpacker85]

Have to agree with both Curly & Ken, but be careful.....if your garage floor is like mine, the glue-up may not come out exactly flat (DAMHIKT).

My workbench is the same construction, but without the hardboard, so I used my 8-year-old $90 Ace Hardware benchtop TS to rip 1/4" off one edge of about 20-8' 2x4's to get a decent surface. I know...hardly the best way to go about it, but it DID achieve the desired result (smoked the old TS & justified the BT3100 ).

Expect to either power plane or belt sand the finished assembly to get the final flatness you want. just my .02

[drkg]

Thanks for the suggestions guys.
I have had the lumber for a week- and I'm not sure how long I should ideally let the lumber sit, but I live in the humid Piedmont Southeast, so I imagine it could take a really long time. I do plan to seal the wood once I get some of the sub assemblies together, I was going to use Ship & Shore dock sealant- bad idea?

Mr. Weaver - you're absolutely right about the jointer/planer decision. I'm not rich by any means, but with a new house (with an attatched 22'X24' shop), a little money and a wife that fully supports my tinkering ways I should be able to get a shop up and running in relatively short order.
I'm thinking I can use my router for the low volume jointing I will be doing for the time being, but I'd really like a planer. I HAD been impressed with the hardwood selection at my local box store, until I found a really cool old-school lumber yard not too far from my home. He's got some really great stuff to work with but most of it is rough sawn. The old fella that's turned me on to wood working has got a planer, that he said I could use any time- but I don't want to put him out and invade his shop any more than absolutely necessary. That said, a planer is on my short list. I'm a gunsmith by trade and my shop will have to be triple purpose (guns, cars and wood), so my layout and tooling may go in a direction not quite in line with the format of other folks on this site, but I have been reading it for quite some time and have found all of the advice to be sound and well directed.

Sorry to run at the mouth, but you can tell I'm pretty excited about having a shop at home- I've been in and out of it all morning.

I'll let you all know how the bench top tunrs out.

[SARGE..g-47]

Good morning drkg...

Having built close to 20 work-benches over the couse of 35 years.. your plan is basically sound and is very close to my first work-bench in 1972. I also agree about having capability to remove that hard-board for two reasons.

(1) It will eventually deteriorate to that point from heavy use and hard-board is cheap. It is also very hard and fairly heavy so gravity will normally keep it down if your shop doesn't see major temperature aned humidity changes. I live outside Atlanta so am familar with your southern piedmont. You should be OK. If.. as JR suggested the hard-board starts to curl, you can drill a few pilot holes here and there and counter sink a few sheet metal screws where the head is just below the surface to hold er down.

(2) By having the ability to remove and replace.. it gives you access to the wooden sub-base. Regardless ow how flat you initially get the sub-base and seal it, it's going to move seasonally. In your humidity prone region it will.. trust me. By having capability of removal, you will occasionally have to re-tru that sub-base top which lead to another minute suggestion.

When you add your skirt to the outer perimeter.. I would suggest two things:

(1) Place the hard-board down on your now flattened top and attach the skirt slightly proud of it's height. If you just measure and attach with it proud by 1/4" before you actually put the hard-board down, any dis-crepancy in flatness will not give you true flat combined. When you do attach it with the hardboard already in place, you simply shoot a pass with a hand jointer and you now have a match even with slight discrepancies in the sub-base,

(2) Consider attaching the skirt to the sides of the top with relatively large head sheet metal screws or fairly small lag bolts. If you don't want metal showing, counter-sink them enough that you can place a tapered wooden plug tapped over the top of the bolt hole. If ya want to get fancy you could even stain the plug a darker color to get contrast but be reminded that Southern Living magazine will most likely be out for a photo-shoot and what you are building is a work-bench. Keep in mind the purpose of a work-bench is to give you a rock solid foundation to build the pretty stuff on top of and in no way does it need to be a pretty itself to do so. ha.. ha...

If you rip just one side of the 2 x 4's you will be fine. The round-over on the other down side won't interfere with anything. I use Watco oil and Butcher's wax on my tables as it it easy to remove when you do have to do the occasional re-true. I flatten with hand planes, but you may not have one so a belt sander works fine. Wear a mask as the saw-dust is going to be everywhere with that tool and not much way to avoid that.

And....... and.. a recommendation to you and several others that have recently joined the forum. I am new also.. but it would be very helpful if you go back in your profile and ADD the location of where you live! If you are in the southern piedmont you might be next door or just down the road from me. If so... I could have been headed your way in my pick-up with a bed full of belt sanders.. hand planes and have saved all this type.

Sorry about the lenght of post.. I could go on, but I have work to do in the shop. When then old man gets on a roll... he ROLLS! That is not necessarily a good thing unless... that energy can be harnessed into something that will benefit a purpose.. ha.. ha... ha.. ha..ha..

Regards...

[eddy merckx]

If you haven't looked at "Bob and Dave's Good, Fast, and Cheap Bench" design, it might be worth checking out. There is a lot of good advice regarding glue up on a 2x4 bench top.

Eddy

[Ken Weaver]

If you found a good lumber yard with good selection of rough sawn, you've already made up your mind - they will pay for themselves in short order. I envy your free standing shop - that's my dream. A lot of folks here have the Ridgid 6 1/2" jointer and Ridgid 13" planer - as I do. they're nice machines at a reasonable price, watch the BORG sales.

[drkg]

Ken - Before I let you get too jealous over my shop, let me explain. My shop is actually the attatched 2-car garage on my house. You see when we were house hunting here in NC we found two houses for the same price. The one I wanted had an inground swiming pool and detatched 25'X35' cinder block shop w/ 20' ceilings and its own bathroom (think auto-lift, turret machine lathe and keg 'fridge) but it was kinda too good to be true. The house needed quite a bit of work (which I was willing to do), was an hour and a half drive for her to work and would have been a nightmare to resell (it had been on the market for two years).
The house we ended up with was brand new contruction, had a bigger plot, in a development (with HO association (EEEKK!!!)) - and an attatched 2 car garage.
In my negotiations with the lady of the house, I won the garage for my shop. NOTHING was to be put in the 'shop' without expressed written consent from yours truely and would remain there for a term not to exceed that specified on the contract!!! - so the shop is mine for tools, projects and my stockpile of Leinenkugels beer I have to smuggle in from Wisconsin.

Anyway, the bench is comeing along sweetly!! I got the bench tops laminated and sitting atop the leg assemblies. When I finally got to flip the tops over they turned out much flatter than I had figured they would. I'll get to planing them tonight or tomorrow after work. And...somehow, the legs turned out level, without adjustment, on the first try- I must have logged some good woodworker's karma somewhere (just waiting to pinch my thumb in a screw or something!!). Will try to post pictures later this week if I get to finish them. Thanks for all the advice thus far.