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

[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.

[Kamikaze]

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

I work a lot with the 8020 products and it is fine for static displays and fixtures but I would advise against using it as part of a fixture that would be moved or have sliding / friction surfaces as the aluminum wears.

It is rigid but requires constant re-tightening and if things are moved about, the tend to "wiggle" the joints and things tend to wobble about after awhile.

[Freelance Fabber]

I like your idea, you could probably get away with 1-1/4 into 1-1/2 tubing. its a bit loose but if you drilled some holes and welded some threaded nuts to the outer tube, you could thread in bolts to tighten up the table at whichever position you wanted. It kinda looks like you drew that in already. To reduce the risk of swayback you could opt to have your inner tubes be seperate pieces from your table frame which can simply be slipped through seperatly as you adjust your table, have them double up on each other for the entire length of the table (perhaps a shorter set for when you want the tables in the compact configuration)

Honestly though, I think you will end up spreading out the table to its entire length for 99% of your work and you will probably be wishing you made a 1 piece top for it.

Unless you need to fold it up and put the table aside after each project I think you will find yourself wanting a solid 1 piece flat table to work on.

Cheers

[SmokinPRanch]

I work a lot with the 8020 products and it is fine for static displays and fixtures but I would advise against using it as part of a fixture that would be moved or have sliding / friction surfaces as the aluminum wears.

It is rigid but requires constant re-tightening and if things are moved about, the tend to "wiggle" the joints and things tend to wobble about after awhile.

Thanks for the clarification. I have limited experience with the 80/20 but knew they did some linear stuff. Never considered the wear issues of the aluminum.

Al