Welding table idea - feedback?

[lens42]

Attached is a Google Sketchup drawing of a welding table idea (not built yet). I'd like to get opinions. The idea is to make the table small for my limited space, but also have it expandable when needed. The drawing shows the bottom view with 2" x 1/8" square tubes with nuts welded so bolts can clamp the cross bars. I'm not yet sure what tubing sizes telescope well, so the tubing might have to change (seeking advice in this too)

The cool thing is that when slid shut, it's a solid (hopefully flat) top, but then gaps can be opened for mid-table clamping. I figure the top is 3 pieces of 12" x 30" x 3/8"(maybe be even 1/4" since it's pretty well supported with 2" angle around the edge.). When shut, the table is 30" x 36", but it can be opened to 5 feet, and even wider with longer bars.

The pluses I see with this are adjustability, mid-table clamping, and that its made of smaller pieces that I can handle without risking my back. The down sides are that I have to make lots of pieces for this and get the telescoping to work, and the risk that the results won't end up as flat as I'd like. I'm also on the fence about tacking or bolting the top on. With 12" x 30" top sections, I can fit them on my mill and put in some tapered holes.

Whadyall think?

[SundownIII]

Lens,

Good concept. Obviously you put a fair amount of thought into what you needed.

My concern, would be bringing the thought to reality.

The way that table is designed would be "very" expensive to build and "very" difficult to execute.

As you mentioned you haven't done a lot of research on what tube fits inside another tube. Problem is most "tube" has a welded seam on the inside which prohibits a "tight fit". To aleviate this you would probably want to use "receiver tube" like for a trailer hitch (true 2" ID with no seam). Don't know if you've priced receiver tube lately, but a stick isn't cheap.

Aligning and maintaining alignment during fabrication will be a real challenge. Welding will definitely "move" your pieces around. A slight warp will cause the male parts to bind in the receiver.

And, all this to basically gain a little working surface.

As I mentioned, looks good on paper (good thought) but may be "extremely" difficult and expensive to produce in the real world.

[AnotherDano]

Does your dining room table have a removable leaf? If not, I bet you know someone who has one that does. Crawl under there and get some pointers and ideas. Most of them have cam-lock devices that draw the sections together - great feature that you might want to incorporate.

[SmokinPRanch]

Interesting design. Looks like it would be portable and modular. Some experimentation and prototyping would be needed to verify the concept works in the real world but it look to be a worthwhile pursuit.

One thing that might work to alleviate the seam weld interference...mill a shallow groove in the insert tubing to allow clearance for the seam weld protrusion of the receiving tube.

I've never actually done it so some research would be in order. I've never given much thought as to the the consistency of location of the seam weld on tubing. And the insert tube would have to be of heavy enough wall to allow milling a groove of suitable depth and maintain required strength. Also I'm not sure how well tubing would fit inside one another over longer distances and tighter tolerances.

Of course also adds to fabrication time and maybe expense. But just a thought.

AL

[Jack Olsen]

I think it's a smart idea, but the part that would worry me is the telescoping tubing. Over time, and with enough hammering, I think you'll be vulnerable to the thing becoming swaybacked instead of flat. And if you use stock heavy enough (and like SmokinPRranch says, without the weld line), it might become very difficult to expand/compress -- and expensive.

It might make more sense to think of two separate tables, each with their own set of four legs, and have the two table tops (and their substructure) interlock -- almost like a yin yang symbol, but with right angles, and probably with even more 'peninsulas and coves,' if that makes any sense. (I wish I could draw a picture.)

It's a cool concept, without a doubt.

[SmokinPRanch]

Another thought...

Check out http://www.8020.net Their extrusions might be able to be incorporated into your concept.

Keep us posted as you progress.

Al

[fjk]

i'd second sundowiii's comments.
i think it would end up being a female-dog
to keep everything lined up right and all that.

instead, i'd build a base smaller table and maybe
consider add-on extensions of some form to use
when doing something "big" maybe not even an
extension to the table, per se, but rather just a
stand that can be repositioned as needed.

what are you proposing to work on
(primarily)?
that would in part help figure out the
"best" course of action

frank

[Showdog75]

If you've got access to a lathe with a four jaw chuck you can offset the outer tube and use a boring bar to machine out the seam.Just a thought.

[Blondie_486]

To eliminate the weld seam in the receiver tubes you can use DOM (drawn over mandrel) tubing, it's a little more expensive but worth it if you want to telescope them. I telescope tubing frequently in some of the conveyors that I build that have to be height adjustable. You will never find a "tight" fit but you can find tubing that will work. When you weld the receiver tubes to the top you'd need to have all 3 pieces of the table top lying flat. Using a length of the inner tubing you can then align and weld the receiver tubes to the table and each other. I would only use small stitch welds to hold the top to the tubes so you don't warp it too much. I'd also use a heavy wall thickness on the tubes to prevent it from becoming a sway back nag in case you put heavy projects on it. I wouldn't use anything less than 3/8" for the top either.

Your idea can and will work if done properly. I think it is a good idea for limited space applications. Just don't put too heavy of projects on it and don't use it as an anvil either and beat the crap out of it.

[MMW]

For the outer tubing use 3/16" wall & then the inner should fit. So a 2" od tube with 3/16" wall gives you an id of 1.625 & that will let a 1.5" od tube slide into it even with the weld seam. Depending on how much weight & pounding will go on top of it will determine how big the tubes & plate should be. You could make a table with hinged ends & drop legs, kinda like a buffet table to save space when not in use. Your idea is o/k but will take a lot of time for a novice to build it right so it works. If you got nothing but time then go ahead.