4' X 8' Table? Why?

[Clockwork]

This isn’t a build log. I’m posting in this forum because it appears that this is where the brain trust for larger machines resides.

I’ve built a number of smaller format machines and started accumulating parts for a large format machine 3 years ago. My initial plan was to build a 4’ X 8’ table – mostly because that’s what a lot of other people were doing.

Looks like the final pieces are about to fall into place as I’ve finally found an acceptable solution for the long axis (didn’t want to use R&P). I uncovered an incredible deal on a couple linear actuators that employ Ballscrews with 6’ of travel. I’m now looking at a compromise format that will have a X-Y cutting area of 3 1/2’ X 6’ on a 4’ X 8’ table.

Back to the original question. What are people building with 4’ X 8’ tables that would involve use of the entire bed, or the entire length of the 8’ axis?

What type of hold down system would one use in cutting out many small pieces from a single large sheet?

From my experience, the best earning potential from sheet goods is in fabricating parts from Baltic Birch, which comes in 5’ X 5’ sheets.

Can picture some rare or specialized applications, such as making 8’ signs.

My current machines have taken me on journeys that I couldn't imagine at the time I built them. I want to fully understand the impact of this compromise on future potential projects. What will I be missing out on?

So, what are the users of 4’ X 8’ tables doing with their machines that cannot be accomplished on a 3 ½’ X 6’ table?

[Bob La Londe]

Boat parts for the stitch and glue builders comes to mind right away.

[ger21]

Cutting 4x8 sheets of material. Usually cabinet making.

Vacuum works well for 4x8 tables. If they're not too small, you can onion skin smaller parts with vacuum.

[CarveOne]

Mine is 12 feet long because:

1. The steel tubing came in 24' lengths. Cut it in half, butt two 6' racks together on each side, and I have a 12' machine with no scrap steel tubing.

2. There is plenty of "work bench" available when I don't need to use the excess space. Aside from accumulating tools, it can be used for project layout and temporary storage space while working on projects.

3. A lathe function can be placed near the end of the table on a semi-temporary basis.

4. It's as wide and 2' longer than my friend's 5'x10' MechMate.

CarveOne

[Clockwork]

Thanks for all of the comments so far. Nothing there that would impact me.

I did find this video. Unfortunately I was preoccupied with how cheaply the megabuck Shopbot was constructed as compared to many of the builds in this forum. What especially caught my eye was their method of controlling backlash on the Z axis.

"http://www.youtube.com/watch?v=0Y8LFyyr09k&feature=related"]Triple Bunk Bed made with the ShopBot CNC router - YouTube

[louieatienza]

Cool... but did they do an FEA on that frame?

[TrickyCNC]

I would say, as sheet stock comes in 8' x 4', then if you use enough full sheets, then it has to be convenient to be able to nest all your cuts onto one sheet ! ?

[Clockwork]

Louie

I had the same thoughts. Looks like it could turn into a House of Cards.

[RossMosh]

Cool... but did they do an FEA on that frame?

I'd be more concerned with the fact that it doesn't seem anything is screwed, glued, or bolted together.

I really doubt you'd have any material failure. By the time you see any stressing of the material, it will probably be time to throw it in the trash. Considering it's probably just 2 pieces of plywood; I doubt anyone will care.

As for why 4x8? Sheet goods come in 4x8 pieces.