Building a BIG frame

[just_doug]

Even though most things I do are usually no more than one or two feet square I decided I needed a Large Table, because.... you just never know.  So I bought enough 80/20 aluminum to build a 4 x 8 foot table.  I have 20 feet of belt on the way and I am hoping the Open-Build wheels I bought a bit ago will fit the profile.  The slot is 5 mm wide as opposed to the 6 mm that came with the Chinese clone.  Also, has anyone ever had trouble with dimensional accuracy over such long distances?  Any other issues that maybe I haven't thought of?  I want to be able to engrave whole table tops.

[ggallant571]

For the acid test you could be fastened to the table and an image taken, converted to a vector outline, and etched into the table top surface without touching you!!!! If you take a video, please omit the sound.

[just_doug]

A guy would have to be Really confident of his work.  I got this... Here, hold my beer....

[ggallant571]

But it cuts and cauterizes at the same time.

[BigAlienRobot]

I built an approximately 3 ft x 3 ft frame to do 27” round tabletops and haven’t had any accuracy issues. I think you’ll be okay and would love to see a photo when you’re done! I would highly suggest drag chains for your cabling as that was the biggest improvement by far for my setup. I recently rebuilt the whole thing and adding them eliminated sooooo many issues. Amazing how no matter how well you think you’ve got cables situated, somehow they always find a way to snag a motor and ruin a piece.

[just_doug]

Frame is together.  You can see my old frame there in the center, sort of disassembled.  That 10 watt Endurance looks pretty small on there.  I still have to make up motor control cables, I don't think I could find 10 foot cables that would just plug in.  Table surface needs leveling yet also.  When I was mounting the laser carriage I noticed there is a bit of side flex in the gantry.  That will need testing.

[Hokuro]

Great 

[just_doug]

Well, I ended up having to replace the 8 foot traveler from 80/20 with a custom cut one from Open Builds.  (O.B. normally only sells 1 and 1.5 meter pieces of V-Slot)  Those 'lil white POM wheels that came with the original setup fit the 5mm slot in the 80/20 but you couldn't cut a straight line if your life depended on it.  The Extreme wheels from O. B. are a twin bearing setup, and most importantly, they are perfectly Round.  Total out of pocket including the extra rail..... just under $200.

[ggallant571]

And here I was trying to figure if it was easier to replace 500mm rails with 300mm or cut the existing. Seldom exceed 200x200mm burn size.