Flat working/assembly surface

[9fingers]

How do you guys get a truly flat surface to use for glue-ups etc.

Today I've been making M&T doors for my new workshop. The only bench I have is 4 scaffold boards on builders trestles and whilst strong,is by no means flat.
So far I've been really careful to plane up the timber dead square, check the tenon shoulders are true and dry fit everything and fine tune if needed.
The doors have come out pretty flat but it started me thinking how I should have done it properly.
Unless I use a metal bench,almost anything I make out of wood is going to move with changes in humidity so back to the question.

How do i get a longlasting reference surface to assemble things square and true?

regards

Bob

 

[PowerTool]

Last time I made some doors for a built-in wardrobe,I made an assembly jig based on a whole sheet of MDF - adequately flat,square,stable and cheap.

Andrew

 

[9fingers]

Hi Andrew,
Thanks for your reply.
I guess MDF would be OK in the short term but it is terrible for soaking up atmospheric moisture. A while back I put a micrometer on a number of MDF scraps in the garage and nominal 18mm sheet varied by over 1.5mm.
Also MDF can't support its own weight so it still needs a level surface to support it.

Chickens & eggs come to mind.

Bob

 

[Paul Kierstead]

Unless I use a metal bench,almost anything I make out of wood is going to move with changes in humidity so back to the question.

It's all relative. A well made wooden bench will move a little, but correctly designed it will move without warping to any significant degree. A few hundred years of craftsman have found them sufficient.

 

[Scott]

Bob

My workshop is a bit makeshift at the moment but I'm using an old formica tabletop on trestles. It's about 50mm thick with beech lipping and shiny white surface on top.

It was in the cow shed and heading for the tip but I'm glad I saved it now because it's actually quite good.

I draw temporary "rods" on the white surface occasionally and it's sufficiently flat and stable for glue-ups (the glue is pretty easy to get off too). I'll build a cabinet to go under it in due course and make it a permanent fixture.

Cheers

 

[mailee]

Although I haven't got one yet, ( I too use some board on trestles) I intend making a sheet of something stable that can be folded up to the wall out of the way when not in use. A pair of folding legs on one side should suffice to support the framework when it is in the down position.

 

[Pecker]

Fire doors! 1/2 hr fire check doors (especially if you can get damaged ones from Howdens) are about £16 each . They make good workbenches.
I've also made them from 3/4 ply and currently one side of the workshop has a kitchen worktop - 3mtrs long £5 from howdens due to being damged.

mark

 

[Alf]

Unless I use a metal bench,almost anything I make out of wood is going to move with changes in humidity so back to the question.

You might need to be looking at keeping those variations in workshop humidity down a bit if that's a serious issue.

Cheers, Alf

 

[bill d]

It's a problem. I'm using a 2 metre piece of thick kitchen worktop left over from a job at the moment. It's stayed flat for about 5 months so far but I check it each time before using it. I set it up on trestles. Expensive if you have to buy it separately though.

 

[Anonymous]

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[Scrit]

I guess MDF would be OK in the short term but it is terrible for soaking up atmospheric moisture.....

The solution to that is to seal it with polyurethane or the like. A bigger problem is that MDF flexes.

Like Scott, though, I frequently resort to kitchen worktops (customer scrap) on top of fold-up plastic trestles when I need extra workbench space. The laminate wipes/scrapes clean easily and all you really need to do is ensure that the backs and ends are sealed or laminated to stop movement. I've also used 60 minute fire doors in the past (in fact I still have a workbench with a top made from one) - watermarked or damaged they aren't too expensive and once sealed with polyurethane varnish and waxed they're stable and easy to keep clean.

Scrit

 

[Guy]

Make yourself a good sized torsion box, run a lenth of 4*2 along the wall ell anchored and attatch the torsion box to it with hinges. Add 2 4*2 one at each end for the legs.
When its not in use just lift it up out of the way and secure with a padbolt.
Ive made one wich is 900 * 3000mm and have been using it for past 4 years without any problems and have had no sagging in it at all, its 100mm thick and top and bottoms were rabbitted

Guy

 

[woodbloke]

I use a dedicated table made about 4' x 2' behind my Kity saw, so its has a double purpose as a take off table and glue up surface. The table is made from beech with a centre braced top and surfaced with chipboard. additionally I have left an overhang of about 2" on three sides so that work can be cramped to it - very useful - Rob

 

[ike]

My solution - 3/4" good quality ply over 2" timber planks on very sturdy bench frame (4 x 4" legs, 4" x 2" and 6" x 2" rails).

Ike

 

[orangetlh]

I use the same method as jacob, 2 3x3 bearers planed square and flat and i just sight them through to make sure they arnt in twist. Doesnt matter how level or twisted your bench is then, you can even glue up on the floor.

 

[Simoli]

I have an assembly table that is flat. The table is a 4' x 8' maple top 2 1/2" think with a layer of laminate on top to keep the surface slippery. Almost all of my assembly work is done here including general bench type of work. I reserve my workbenches for hand tool work.

 

[Newbie_Neil]

Hi Jim

Welcome to the forum.

Cheers
Neil

 

[Drew]

simplest way of all is get two or three straight pieces of timber. Fasten one to your bench, space the others out and wind them in by eye, pack them up, fasten them down and there you have a flat surface to assemble on. It takes five minutes at most.

Drew